H. Symbol for hydrogen, the molecular formula is 5400C, high thermal neutron cross section (115

barns). Good corrosive resistance and high strength.

See zirconium.

Occurrence: Zirconium ores.

h. See Planck’s constant.

Derivation: Extremely difficult to separate from zir-

conium. Most important methods are: (1) solvent

Haber, Fritz. (1868–1934). Born in Breslau,

extraction of the thiocyanates by hexone, (2) solvent

Germany, Haber’s great contribution to chemistry,

extraction of the nitrates by tributyl phosphate, (3)

for which he was awarded the Nobel Prize in 1918,

fractional crystalization of the double fluorides.

was his development (with Bosch) of a workable

Available forms: Powder, rods, single crystals.

method for synthesizing ammonia by the water-gas

Hazard: Toxic by inhalation; compounds are also

reaction from hot coke, air, and steam; the gas mix-

toxic. Powder form is explosive in air, either dry or

ture obtained includes nitrogen from the air, as well

wet, with less than 25% water. TLV: 0.5 mg/m

as hydrogen from the steam. It was the first success-

Use: Control rods in water-cooled nuclear reactors;

ful attempt to “fix” atmospheric nitrogen in an in-

lightbulb filaments, electrodes, special glasses, get-

dustrial process. This discovery was developed to

ter in vacuum tubes.

production scale in approximately 1912; it enabled

Germany to manufacture an independent supply of

hafnium boride. HfB

. Crystalline solid, mp

explosives for World War I.

3100C.

Use: Refractory material.

habit. The type of geometric structure that a given

crystalline material invariably forms, e.g., cubic,

hafnium carbide. HfC.

orthorhombic, monoclinic, tetragonal, hexagonal,

Properties: High thermal neutron absorption cross

etc. Each of these types has several subclasses.

section. Very high mp 3890C (7030F). Most refrac-

Thus, crystals may have the form of thin sheets or

tory binary substance known.

plates, cubes, rhomboids, and even more complicat-

Use: Control rods in nuclear reactors.

ed geometric structures. For example, the crystalline

habit of mica is monoclinic, with formation of ex-

tremely thin sheets.

hafnium disulfide. HfS

. Available in a particle

See crystal.

size of 40 microns as a solid lubricant. The diselen-

ide and ditelluride are also available.

H acid. (1-amino-8-napthol-3,6-disulfonic

acid).

hafnium nitride. HfN. Yellow-brown crystals,

Properties: Gray powder. Soluble in water, alcohol,

mp 3305C, the most refractory of known metal ni-

and ether.

trides.

hafnium oxide. (hafnia). HfO

Properties: White solid. D 9.68 (20C), mp 2812C, bp

approximately 5400C. Insoluble in water.

Use: Refractory metal oxide.

Hahn, Otto. (1879–1968). A German physical

Derivation: Fusion of 1-naphthylamine-3,6,8-trisul-

chemist who won the Nobel Prize for chemistry in

fonic acid (Koch acid) with 30% sodium hydroxide

1944 for atom splitting and the principle of the chain

solution at 180C.

reaction. Well-known for work on nuclear fission he

Use: Azo dye intermediate.

discovered protactinium and transuranium elements

with atomic numbers 94, 95, and 96. After receiving

his doctorate at the University of Munich, he worked

haemo-. Prefix indicating relationship to blood.

in Canada before returning to Europe.

hafnia. See hafnium oxide.

hair. See keratin.

hafnium.

CAS: 7440-58-6. Hf. Metallic element of atomic halazone. (p-N,N-dichlorosulfamylbenzoic

number 72, Group IVB of the periodic table, aw acid; p-sulfondichloraminobenzoic acid).

178.49, valences of 2, 3, 4; 6 stable isotopes. CAS: 80-13-7. HOOCC

NCl

Properties: Generally similar to zirconium. Gray Properties: White crystalline powder; strong chlo-

crystals. D 13.1, mp approximately 2150C, bp above rine odor. Mp 195C with decomposition. Affected

628

629 HALOGENATION

by light. Soluble in glacial acetic acid, benzene; alumina extracted from it (see Bayer process). A

slightly soluble in water, chloroform; insoluble in typical cell for this process consists of a rectangular

petroleum ether. steel shell lined with insulating brick and block

carbon. The cell holds a molten cryolite-alumina

Grade: NF.

electrolyte, commonly called the “bath.” The carbon

Use: Water disinfectant.

bottom is covered by a pad of molten aluminum and

serves as the cathode. The anodes are prebacked

half-life. The time required for an unstable ele-

carbon blocks suspended in the electrolyte. The ca-

ment or nuclide to lose one-half of its radioactive

thodic current is collected from the carbon bottom

intensity in the form of ␣, ␤, and ␥ radiation. It is a

by embedded steel bars that protrude through the

constant for each radioactive element or nuclide.

shell to connect with the cathode bus. During elec-

Half-lives vary from fractions of a second for some

trolysis, aluminum is deposited on the metal pad,

artificially produced radioactive elements to mil-

and the oxygen, liberated at the anode, reacts with

lions of years. The half-life of

235

U is 7.1 × 10

years;

the carbon to form carbon dioxide, some of which is

that of

239

Pu is 24,360 years.

reduced to carbon monoxide by secondary reac-

tions. At 24–48-h intervals, aluminum is tapped

halibut liver oil. (haliver oil).

from the cell by a siphon. The process requires large

Properties: Pale-yellow to dark-red liquid; fishy

amounts of electric power (from 4–5% of total U.S.

odor and taste. D 0.920–0.930, saponification num-

production). Disposition of the toxic fluoride waste

ber 160–180, iodine number 120–136, refr index

is a problem.

about 1.47. Soluble in alcohol, ether, chloroform,

See Toth process.

and carbon disulfide; insoluble in water.

Derivation: By expressing and boiling halibut livers.

hallucinogen. Any of a number of drugs acting

Grade: Crude, refined.

on the central nervous system in such a way as to

Use: Source of vitamins A and D, leather dressing.

cause mental disturbance, imaginary experiences,

coma, and even death. Many of these are narcotics

halides. Binary compounds of the halogens.

and/or alkaloids; some are derived from plants, and

others are made synthetically. They differ in degree

halite. The mineral that consists of sodium chlo-

of addiction and hallucinatory effect. Their sale and

ride (NaCl), popularly known as rock salt, or the

possession (other than by physicians) is illegal in the

rock that consists primarily of this mineral.

U.S. The most common hallucinogens are cannabis

(marijuana, hashish), lysergic acid (LSD), amphet-

Hall, Charles Martin. (1863–1914). A native

amine, and numerous morphine derivatives.

of Ohio, Hall invented a method of reducing alumi-

num oxide in molten cryolite by electrochemical

halocarbon. A compound containing carbon,

means. This discovery made possible the large-scale

one or more halogens, and sometimes hydrogen.

production of metallic aluminum and resulted in

The lower members of the various homologous se-

formation of the Aluminum Company of America.

ries are used as refrigerants, propellant gases, fire-

The process requires high electric power input. Hall

extinguishing agents, and blowing agents for ure-

is generally considered the founder of the aluminum

thane foams. When polymerized, they yield plastics

industry.

characterized by extreme chemical resistance, high

See Hall process.

electrical resistivity, and good heat resistance.

See fluorocarbon.

“Hallco” [Hall]. TM for specialty esters based

on acetic, lauric, and sebacic acids.

halocarbon 112a. See 1,1,2-tetrachloro-2,2-

difluoroethane.

“Hallcomid” [Hall]. TM for a series ofN,N

′

dimethyl amides and esters of fatty acids.

halofuginone hydrobromide.

mf: C

CIN

“Hallcote” [Hall]. TM for clay containing anti-

Properties: Crystals.

blocking coatings (slab dips) used in rubber pro-

Use: Drug (veterinary); food additive.

cessing.

halogen. One of the electronegative elements of

Haller-Bauer reaction. Cleavage of nonenol-

group VII A of the periodic table (fluorine, chlorine,

izable ketones with sodium amide, most often ap-

bromine, iodine, astatine, listed in order of their

plied to ketones ArCOCR

to yield trisubstituted

activity, fluorine being the most active of all chemi-

acetic acids.

cal elements).

halloysite. Al

•3SiO

•2H

O. A clay used in

refactories and as a catalyst support.

halogenation. Incorporation of one of the halo-

gen elements, usually chlorine or bromine, into a

Hall process. The electrolytic recovery of alu- chemical compound. Thus benzene (C

) is treated

minum from bauxite or, more specifically, from the with chlorine to form chlorobenzene (C

Cl), and

630“HALON”

ethylene (C

) is treated with bromine to form Hamiltonian function. An expression of the

sum of potential and kinetic energy in a system in

ethylene dibromide (C

). Compounds of chlo-

terms of Cartesian coordinates and momenta.

rine and bromine are sometimes used as the source

of the halogen, e.g., phosphorus pentachloride.

hammer mill. A crushing or shredding device

“Halon” [Great Lakes]. TM for tetrafluoro-

consisting of four or more rectangular metal ham-

ethylene polymer.

mers or sledges mounted on a rotating shaft, the

Properties: Inertness to almost all chemicals, resis-

hammers being free to swing on a pin. As the shaft

tance to high and low temperatures, zero moisture

rotates, the hammers impact the material introduced

absorption, high impact strength, excellent dielec-

from above, crushing it against a stationary breaker

tric properties, nonstick surface with low coefficient

plate. The fragments are carried downward and sort-

of friction, self-extinguishing (ASTM D-635).

ed by a grid located beneath the shaft; those too large

Grade: Varies with particle size as 600-, 300-, 20-

to pass through it are returned for another cycle. A

micron average size.

complete mill is made up of several such units work-

See polytetrafluoroethylene; fluorocarbon polymer.

ing on a single shaft, with suitable housing. Products

such as coal, limestone, and other mineral aggre-

“Halon 1211” [Great Lakes]. (bromochlo-

gates, as well as wood, sugarcane, and similar mate-

rodifluoromethane).

rials, can be effectively disintegrated with equip-

CAS: 353-59-3. TM for a compressed gas.

ment of this type.

Use: Fire-extinguisher compound.

Hammick reaction. Decarboxylation of ␣-pi-

Halon 1301. See trifluorobromomethane.

colinic or related acids in the presence of carbonyl

compounds accompanied by the formation of a new

halosafen. See 5-(2-chloro-6-fluoro-4-(trifluo-

carbon-carbon bond.

romethyl)phenoxy)-n.

Hammond-Leffler postulate. States that the

halothane. (2-bromo-2-chloro-1,1,1-trifluoroe-

structure of the transition state more closely resem-

thane).

bles the product or the starting material, depending

CAS: 151-67-7. CF

CHBrCl.

on which is higher in enthalpy.

Properties: Colorless, volatile liquid; sweetish odor.

D 1.872–1.877 (20/4C), bp 50.2C, 20C (243 mm

“Hampamide” [Grace]. TM for mixtures of

Hg). Light sensitive. May be stabilized with 0.01%

mono-, di-, and triamides of nitrailotriacetic acid in

thymol. Slightly soluble in water; miscible with

solution of dry salt form.

many organic solvents.

Grade: USP.

“Hamp-ene” [Grace]. TM for chemical com-

Hazard: TLV: 50 ppm; not classifiable as a human

positions comprising amino acid or carbohydrate

carcinogen.

chelating or sequestering agents or compositions

Use: Medicine (anesthetic).

containing such sequestering agents.

Available forms: Bulk and package.

Halowax 1051. See octachloronaphthalene.

Hamilton, Alice. (1869–1970). The first Amer-

“Hamp-Ex” [Grace]. TM for chemical com-

ican physician to devote her life to the practice of

positions comprising amino acid or carbohydrate

industrial medicine. In studying the lead industries

chelating or sequestering agents or compositions

in Illinois, she discovered and ameliorated lead poi-

containing such sequestering agents.

soning among bathtub enamelers in Chicago. She

Available forms: Bulk and package form.

wrote about phossy jaw, which occurred among

American matchmakers who used white or yellow

“Hampirex” [Grace]. TM for chelated micro-

phosphorus. She studied the effects of carbon mon-

nutrients.

oxide among steelworkers, the toxicity of nitroglyc-

erin among munitions makers during World War I,

“Hamp-Iron” [Grace]. TM for iron chelates

the symptoms of hatters exposed to mercury in Dan-

for agricultural purposes.

bury, Connecticut, and the “dead fingers” syndrome

of workers utilizing the early jackhammers. She also

“Hamp-Ol” [Grace]. TM for chemical compo-

described the toxic effects to the blood-forming cells

sitions comprising amino acid or carbohydrate che-

from benzol, and the neurologic and psychological

lating or sequestering agents or compositions con-

responses of workers in the viscose rayon industry.

taining such sequestering agents.

In 1919, Dr. Hamilton was appointed assistant pro-

Available forms: Bulk and package form.

fessor of industrial medicine at Harvard Medical

School. The first woman on the Harvard faculty, she

gave occupational medicine respectability as an aca-

“Hamposyl” [Grace]. TM for chemically

demic pursuit. modified fatty acids.

631 HARDY-WEINBERG LAW

“Hampshire” [Grace]. TM for chemical prod- haplotype. A way of denoting the collective ge-

ucts, namely, amino acids, chelating agents, metal

notype of a number of closely linked loci on a chro-

chelates, surfactants, sequestering agents, and

mosome.

resins.

haptoglobin. A serum protein which binds free

hemoglobin for transport to the liver for destruction.

“Hamp-Tex” [Grace]. TM for chelating agent

for textile applications.

“Harborlite” [World Minerals]. TM for

perlite minerals and mineral substances.

hand. (handle). A term used chiefly in the textile

Use: Filtration for industry, agriculture, horticulture,

industry to describe a fabric in a qualitative manner,

and forestry applications.

as determined by the sensory perception of its feel-

ing. It is also used to some extent in the leather

hard. A nontechnical word, used by chemists, that

industry. Such pragmatic physical-perception tests

has a variety of meanings. It describes the following:

are of great practical value, although the properties

(1) Water in which calcium carbonate or calcium

being ascertained are often not objectively defina-

sulfate is present.

ble.

See water, hard.

See texture.

(2) An acid having high positive oxidation and

whose valence electrons are not readily excited.

handedness. See asymmetry; enantiomer;

See acid.

chiral.

(3) Extremely short-wave radiation, e.g., hard X

rays.

“Hansa” [BASF]. TM for a group of yellow to

(4) The resistance of a pesticide or detergent to

orange, insoluble azo pigments based on toluidine

biodegradation.

and ␤-naphthol. Have good light fastness in deep

(5) Rubber cured with 30% or more of sulfur. See

shades but tend to fade in pastels. Notably poor

rubber, hard.

resistance to bleeding, good weather resistance, and

(6) Wood from deciduous trees. See hardwood;

relatively unaffected by acids and alkalies. Used

hardness.

chiefly in emulsion paints, toy enamels, and other

applications.

Harden, Sir Arthur. (1865–1940). An En-

glish chemist who won the Nobel Prize in chemistry

Hantach pyrrole synthesis. Formation of

in 1929 along with Hans von-Euler-Chelpin. He

pyrrole derivatives from ␣-chloromethyl ketone, ␤-

discovered fermentation enzymes and demonstrated

keto esters, and ammonia or amines.

the structure of zymase. His fermentation work

proved how inorganic phosphates speeded the pro-

cess. Born in England, he received his doctorate in

Hantzch pyridine synthesis. Synthesis of

Germany.

alkylpyridines by condensation of two moles of a ␤-

dicarbonyl compound with one mole of an aldehyde

hardness. The resistance of a material to defor-

in the presence of ammonia. The resulting dihydro-

mation of an indenter of specific size and shape

pyridine is dehydrogenated with an oxidizing agent.

under a known load. This definition applies to all

types of hardness scales except the Mohs scale,

Hanus reagent. Reagent consisting of 20% io-

which is based on the concept of scratch hardness

dine monobromide in glacial acetic acid.

and is used chiefly for minerals. The most generally

Use: Determination of iodine values.

used hardness scales are Brinell (for cast iron),

Rockwell (for sheet metal and heat-treated steel),

haploid. A single set of chromosomes (half the

diamond pyramid, Knoop, and scleroscope (for met-

full set of genetic material), present in the egg and

als). Durometer hardness is used for materials such

sperm cells of animals and in the egg and pollen cells

as rubber and plastics.

of plants. Human beings have 23 chromosomes in

their reproductive cells.

hardwood. In papermaking terminology, the

See: Diploid.

wood from deciduous trees (maple, oak, birch), re-

gardless of whether it is actually hard or soft.

haploid-diploid life cycle. Occurs when a

Use: Components of paper pulp, but in much lower

multicellular diploid phase, or sporophyte, alter-

volume than softwoods.

nates with a multicellular haploid phase, or gameto-

phyte. Only plants and certain algae possess this

Hardy-Weinberg Law. The concept that both

kind of life cycle, which is also called “alternation of

gene frequencies and genotype frequencies will re-

generations”.

main constant from generation to generation in an

infinitely large, interbreeding population in which

haploid life cycle. Occurs when the only mul- mating is at random and there is no selection, migra-

ticellular stage in an organism’s life cycle is haploid. tion or mutation.

632“HARD WATER/ACID”

“Hard Water/Acid Tolerant Synthetic Use: Fabrication into all types of process equipment.

Lube” [Ace]. TM for a conveyor lubricant.

Hauptman, Herbert A. (1917– ). An Ameri-

Hargreaves process. The manufacture of sodi-

can biophysicist who won the Nobel Prize for chem-

um sulfate (salt cake) from sodium chloride and

istry in 1985 along with Karle. Work involved de-

sulfur dioxide. A mixture of sulfur dioxide and air is

veloping equations that allow determination of

passed over briquettes of sodium chloride in a coun-

phase information from X ray crystallography inten-

tercurrent manner to produce sodium sulfate and

sity patterns. The use of computers permitted use of

hydrogen chloride. This process accounts for only a

the equations to determine the conformation of thou-

small amount of the salt cake produced in the U.S.

sands of chemicals. Hauptman was director of re-

search and vice president of the Medical Foundation

Harries ozonide reaction. Treatment of ole-

of Buffalo and a professor of biophysics in Buffalo

fins with ozone as a method of cleaving olefinic

at the State University of New York.

linkages. On hydrolysis or catalytic hydrogenation,

the initially formed ozonide yields two molecules of

“Haveg” [Ametek]. TM for a series of molding

carbonyl compounds.

compounds fabricated into corrosive-resistant

chemical process equipment. Composites of various

“Hartex” [Firestone]. TM for natural rubber

synthetic polymers with silicate fillers.

latex.

Use: Tanks, towers, scrubbers, agitators, piping, etc.

Use: Dipped goods and adhesives.

in the handling of sulfuric, hydrochloric, and phos-

phoric acids and chlorinated solvents. Also used as

hartshorn. See ammonium carbonate.

ablative products to protect metal surfaces from heat

of launching missiles.

hartshorn oil. See bone oil.

“Havelast” [Ametek]. TM for an elastomeric

HAS. Abbreviation for hydroxylamine acid sul-

binder or impregnant for various reinforcing materi-

fate.

als such as “Siltemp,” as fabric or rovings, asbestos,

glass, or graphite.

hashish. Extract of cannabis (marijuana), more

Use: Rocket and missile industry when resiliency is

concentrated and thus more powerful than the base

desired.

drug.

See cannabis.

Haworth methylation. Formation of methyl-

ated methyl glycosides from monosaccharides with

Hass chlorination rules. A series of rules

dimethyl sulfate and 30% sodium hydroxide. The

pertaining to the chlorination of saturated hydro-

glycosidic methyl group is hydrolyzed with acid to

carbons.

yield the free methylated sugar.

Hassel, Odd. (1897–1981). A Norwegian

Haworth perspective formulas. A method

chemist who won the Nobel Prize for chemistry in

for representing cyclic chemical structures (sugars)

1969 with Barton. A great deal of his work was

in order to define the configuration around each

concerned with using X ray and electron differentia-

chiral center.

tion methods of crystal and molecular structures. He

also researched stereochemistry and conformational

Haworth phenanthrene synthesis. Acyla-

analysis. His education and teaching career were in

tion of aromatic compounds with aliphatic dibasic

his homeland.

acid anhydrides to ␤-aroylpropionic acids, reduc-

tion of the carbonyl group according to Clemmensen

hassium. Hs. A transfermium element. Atomic

or Wolff-Kishner procedures, cyclization of the ␥-

number 108. Very short half-life.

arylbutyric acid with 85% sulfuric acid, and conver-

sion of the cyclic ketone to polycyclic hydroaromat-

Hass vapor-phase nitrogen. Production of

ic and subsequently to aromatic compounds.

nitroparaffins by vapor phase reaction of aliphatic

hydrocarbons with gaseous nitric acid at 420C; a

series of thirteen rules governing these reactions.

Haworth, Sir Walter N. (1883–1950). An

English chemist who received the Nobel Prize in

“Hastelloy” [Haynes]. TM for a family of chemistry in 1937 along with Paul Karrer. He rec-

high-strength, nickel-based alloys with a high resis- ommended the name ascorbic acid and synthesized

tance to uniform corrosion, outstanding resistance to vitamin C. He accomplished much work on carbo-

localized attack, and excellent stress corrosion hydrate structure and developed a substitute for

cracking resistance while maintaining ease of weld- blood plasma using carbohydrates. During World

ing and fabrication. War II, he developed gaseous diffusion separation

Available forms: Sheet, plate, bars, rods, welding on uranium isotopes. He received his Ph.D. in Man-

electrodes, and wire. chester.

633 HEAT

Hayashi rearrangement. Rearrangement of Hb. Abbreviation for hemoglobin.

␣-benzoylbenzoic acids in the presence of sulfuric

acid or phosphorus pentoxide.

HCCH. Abbreviation for hexachlorocyclo-

hexane.

“Haynes” [Haynes]. TM for a series of high-

HCE. See epoxyheptachlor.

temperature nickel and cobalt-based alloys designed

to resist high-temperature corrosion processes up to

HCG. Abbreviation for human chorionic gonado-

2200° F. Engineered to provide high temperature

tropin.

strength, resistance to creep, oxidation and sulfida-

tion resistance while maintaining ease of welding

“HCR” [Dow]. TM applied to ion-exchange

and fabrication.

resin used in water-treating and chemical process

Available forms: Sheet, plate, bars, rods, welding

applications; strong acid cation-exchange resin, 8%

electrodes, and wire.

divinylbenzene cross-linked.

Use: Fabrication into all types of process equipment.

HDPE. Abbreviation for high-density polyeth-

“Haystellite” [Cabot]. TM for tungsten car-

ylene.

bide products, principally in the form of hard-sur-

facing rods for protecting parts from severe abra-

He. Symbol for helium.

sion.

HEA. Abbreviation for 2-hydroxyethyl acrylate.

hazardous material. Any material or sub-

stance that in normal use can be damaging to the

head box. A large container, holding the pre-

health and well-being of humans. Such materials

pared slurry of paper pulp and additives, located at

cover a broad range of types that may be classified as

the head of the fourdrinier machine; the slurry is fed

follows: (1) Toxic agents (see poison; toxicity) in-

continuously from slots in the bottom of the box to

cluding drugs, chemicals, and natural or synthetic

the wire on which the sheet is formed.

products that in normal use are in any way harmful,

ranging from poisons to skin irritants and allergens.

head space. A term used in the canning industry

When improperly used, all materials can be hazard-

to refer to the space intentionally left between the

ous to humans.

top of the filled liquid and the cover of the can to

(2) Corrosive chemicals such as sodium hydroxide

allow for expansion of the contents during heat pro-

or sulfuric acid that destroy or otherwise damage the

cessing.

skin and mucous membranes on external contact or

inhalation.

“Healthya Water” [Kao]. TM for first sport

(3) Flammable materials including (a) organic sol-

drink approved as a food for specific health use.

vents, (b) finely divided metals or powders, (c) some

classes of fibers, textiles, or plastics, and (d) chemi-

heat. A form of energy associated with and pro-

cals that either evolve or absorb oxygen during stor-

portional to molecular motion. It can be transferred

age, thus constituting a fire risk in contact with

from one body to another by radiation, conduction,

organic materials.

or convection; unlike latent heat, sensible heat is

(4) Explosives and strong oxidizers such as perox-

accompanied by a change in temperature.

ides and nitrates.

—of combustion: The heat evolved when a definite

(5) Materials in which dangerous heat buildup oc-

quantity of a substance is completely oxidized

curs on storage, either by oxidation or microbiologi-

(burned).

cal action. Examples are fish meal, wet cellulosics,

—of crystallization: The heat evolved or absorbed

and other organic waste materials.

when a crystal forms from a saturated solution of a

(6) Radioactive chemicals that emit ionizing radia-

substance;

tion. Packaging, labeling, and shipping of hazardous

—of dilution: The heat evolved per mole of solute

materials by rail, highway, water, and air are regulat-

when a solution is diluted from one specific concen-

ed in the U.S. by the Department of Transportation

tration to another.

(DOT). In general, its regulations for air shipment

—of formation: The heat evolved or absorbed when

follow those of the International Air Transport As-

a compound is formed in its standard state from

sociation (IATA), though there are numerous points

elements in their standard states at a specified tem-

of difference.

perature and pressure.

An authoritative guide to the safety labeling of haz-

—of fusion: The heat required to convert a substance

ardous materials and products is issued by the Amer-

from the solid to the liquid state with no temperature

ican National Standards Institute. See toxicity;

change (also called latent heat of fusion or melting).

flammable material; label.

—of hydration: The heat associated with the hydra-

tion or solvation of ions in solution; also the heat

hazardous waste. See chemical waste; ra- evolved or absorbed when a hydrate of a compound

dioactive waste. is formed.

634HEAT EXCHANGER

—of reaction: The heat evolved or absorbed when a

heavy metal. A metal of atomic weight greater

chemical reaction occurs in which the final state of than sodium (23) that forms soaps on reaction with

the system is brought to the same temperature and fatty acids, e.g., aluminum, lead, cobalt.

pressure as that of the initial state of the reacting See soap (2).

system.

—of solution: The heat evolved or absorbed when a

heavy oil. An oil distilled from coal tar between

susbtance is dissolved in a solvent.

230C and 330C, the exact range not at all definite.

—of sublimation: The heat required to convert a unit

See coal tar.

mass of a substance from the solid to the vapor state

(sublimation) at a specified temperature and pres-

heavy oxygen. See oxygen-18.

sure without the appearance of the liquid state.

—of transition: The heat evolved or absorbed when

heavy spar. See barite.

a unit mass of a given substance is convereted from

one crystalline form to another.

heavy water. (deuterium oxide; DOD; tritium

—of vaporization: The heat required to convert a

oxide; TOT). Water composed of two atoms of

substance from the liquid to the gaseous state with

deuterium and one atom of oxygen; or one or two

no temperature change (also called latent heat of

atoms of tritium and one of oxygen. In lower states

vaporization).

of purity, the proportion of heavy water molecules

decreases. Deuterium oxide is present to the extent

heat exchanger. A vessel in which an outgoing

of approximately one part in 6500 of ordinary water.

hot liquid or vapor transfers a large part of its heat to

Deuterium oxide freezes at 3.8C, boils at 101.4C,

an incoming cool liquid; in the case of vapors, the

and has density of 1.1056 at (25C).

latent heat of condensation is thus utilized to heat the

Derivation: There are several methods of separating

entering liquid. The shell-and-tube type is widely

or concentrating DOD: (1) fractional distillation, (2)

used; here the hot liquid or vapor is contained in the

Girdler-Spevack process, (3) hydrogen-sulfide ex-

shell while the cool liquid passes through the tubes,

change process, (4) electrolysis, (5) cryogenic meth-

which are usually arranged in coils for maximum

ane distillation.

contact with the heat source. Heat exchangers are

Available forms: DOD 99.75% pure, in up to 5000 g

used in many chemical operations, e.g., evaporation

lots.

and pulp manufacture, as well as to produce steam

Use: Moderator in some types of nuclear reactors.

from the heat developed in nuclear reactors for pow-

Tritium (hydrogen of atomic weight 3) combines

er generation.

with oxygen to give another variety of heavy water,

See evaporation; heat transfer.

TOT, i.e., tritium oxide.

See tritium.

heat transfer. Transmission of thermal energy

from one location to another by means of a tempera-

ture gradient existing between the two locations. It

HEBP. See 2-hydroxyethyl dibutyl phosphate.

may take place by conduction, convection, or radia-

tion. Heat transfer is involved in many types of

hecto-. (h). Prefix meaning 10

units, e.g., 1 hg

industrial operations, including distillation, evapo-

1 hectogram

100 grams.

ration, canning of foods, baking, curing, etc. In some

cases, a heat exchanger is utilized. Fluids of high

hectorite. (hector clay).

heat capacity are widely used to remove unwanted

0.67

(Mg,Li)

(OH,F)

. One of the montmoril-

heat or to transfer it from one place to another within

lonite group of minerals that are principal constitu-

a system; examples are air, water, ethylene glycol.

ents of bentonite.

See coolant.

Hazard: Respiratory irritant.

Use: Chill-proofing of beer.

heavy. A nontechnical word used in a number of

scientific senses: (1) referring to atomic weight

hedeoma oil. See pennyroyal oil.

(heavy water, heavy metal); (2) referring to produc-

tion volume (heavy chemical); (3) referring to phys-

hedonal. (methylpropylcarbinolurethane).

ical weight (heavy spar); (4) referring to thickness

CAS: 120-36-5. CH

CH(CH

)OCONH

(heavy-gauge wire); (5) referring to distillation

Properties: White, crystalline powder; faint aromat-

range (heavy oil).

ic odor and taste. Fusing p 76C, bp 215C. Soluble in

alcohol, ether, organic solvents; sparingly soluble in

heavy chemicals. A chemical produced in ton-

cold water; more soluble in hot water.

nage quantities, often in a relatively impure state.

Use: Medicine (sedative).

Examples are sodium chloride, sulfuric acid, soda

ash, salt cake, sodium hydroxide, etc.

See basic chemicals; fine chemical.

␣-hederine.

CAS: 27013-91-8. mf: C

heavy hydrogen. See deuterium; tritium. Hazard: Low toxicity by ingestion.

635 HELLEBRIGENIN

HEDTA. See ing. All ingredients conform to FDA requirements

hydroxyethylethylenediaminetriacetic acid. for food packaging.

HEED. Abbreviation for high-energy electron

“Heliozone” [Du Pont]. TM for a blend of

diffraction.

waxy material.

Use: Retards sun-checking and cracking of rubbers.

Heeger, Alan J. (1923– ). Awarded Nobel

Prize in chemistry in 2000 jointly with Alan

helium.

G.MacDiarmid and Hideki Shirakawa for the dis-

CAS: 7440-59-7. He. Noble element of atomic num-

covery and development of conductive polymers.

ber 2, first element in the noble gas group of the

He performs his research at Texas Instruments, Dal-

periodic table, aw 4.00260, valence of 0. Helium

las, Texas.

nuclei are alpha particles. Most important isotope is

helium-3.

Hehner number. The percentage of weight of

Properties: Colorless, noncombustible gas; odorless

water-insoluble fatty acids in oils and fats.

and tasteless. Liquefies at 4.2K to form helium I; at

2.2K there is a transition (␭) point at which helium II

Heisenberg, Werner P. (1901–1976). A na-

is formed. See note below.

tive of Germany, Heisenberg received his doctorate

Properties: Bp −268.9C (1 atm), fp −272.2C (25

from the University of Munich in 1923, after which

atm) lowest of any substance, bulk d 0.1785 g/L

he was closely associated for several years with

(0C). Very slightly soluble in water; insoluble in

Niels Bohr in Copenhagen. He was awarded the

alcohol; rate of diffusion through solids is three

Nobel Prize in physics in 1932 for his brilliant work

times that of air; an asphyxiant gas.

in quantum mechanics. In 1946, he became director

See noble gas.

of the Max Planck Institute. His notable contribu-

Occurrence: Texas, Oklahoma, Kansas, New Mexi-

tions to theoretical physics, best known of which

co, Arizona, Canada. Originally discovered in the

was the uncertainty principle, imparted new impetus

sun’s atmosphere (1868) and confirmed in the atmo-

to nuclear physics and made possible a better under-

sphere of Jupiter.

standing of atomic structure and chemical bonding.

Derivation: From natural gas, by liquefaction of all

See uncertainty principle.

other components, followed by purification over

activated charcoal.

helenine. A nucleoprotein derived from the mold

Grade: USP, technical, 99.995% pure.

Penicillium funiculosum.

Use: To pressurize rocket fuels, welding, inert atmo-

Use: An antiviral drug.

sphere (growing germanium and silicon crystals),

inflation of weather and research balloons, heat-

Helferich method. Glycosidation of an acety-

transfer medium, leak detection, chromatography,

lated sugar by heating with a phenol in the presence

cryogenic research, magnetohydrodynamics, lumi-

of zinc chloride or p-toluenesulfonic acid as cata-

nous signs, geological dating, aerodynamic re-

lyst.

search, lasers, diving and space-vehicle breathing

equipment. Possible future uses include coolant for

Helianthine B. See methyl orange.

nuclear fusion power plants and in superconducting

electric systems.

helicase. An enzyme that catalyzes the unwind-

Note: Liquid helium has unique thermodynamic

ing of strands in a DNA molecule before replication.

properties too complex to be adequately described

here. Liquid He I has refr index 1.026, d 0.125, and is

“Helindon” [BASF]. TM for vat dyestuffs

called a “quantum fluid” because it exhibits atomic

used for dyeing wool.

properties on a macroscopic scale. Its bp is near

absolute zero and viscosity is 25 micropoises (water

“Heliogen” [BASF]. TM for phthalocyanine

10,000). He II, formed on cooling He I below its

dyestuffs.

transition point, has the unusual property of super-

Use: Paint, lacquers, printing inks, wallpaper, coated

fluidity, extremely high thermal conductivity, and

paper, rubber, and plastics.

viscosity approaching zero.

See superconductivity.

“Helisorb” [Norquay]. TM for UV stabilizer.

Properties: Free-flowing nonhazardous powder.

helix-loop-helix. A protein structural motif

Use: An effective UV stabilizer for UVA and UVB

characteristic of certain DNA-binding proteins.

protection in low concentrations for cosmetics and

plastics.

hellebrigenin 3-acetate.

“He-Li-Ox” 500 Series [Mallinckrodt]. CAS: 4064-09-9. mf: C

TM for a series of PVC heat stabilizers for extrud- Hazard: A poison.

ing, injection molding, calendering, and blow mold- Source: Natural product.

636HELL-VOLHARD-ZELINSKY

Hell-Volhard-Zelinsky reaction. ␣-Haloge- sorbed by cancerous tissues, making them fluoresce

under UV light.

nation of carboxylic acids with halogen and phos-

Use: Medicine (antidepressant).

phorus, presumably involving the enol form of the

intermediate acyl halide.

hematoxylin.

17-␣-helveticoside.

CAS: 517-28-2. C

•3H

CAS: 6869-17-6. mf: C

Properties: Slightly yellow crystals, turning red in

Hazard: A poison.

light. Mp 100–120C. Soluble in hot water and alco-

Source: Natural product.

hol, in glycerol, and in alkali hydroxides.

Hazard: May be carcinogenic.

hem-. Prefix indicating relationship to blood.

Use: Colorant in inks, biological stains.

HEMA. See hydroxyethyl methacrylate.

heme. (hem). C

FeN

. The nonprotein por-

tion of hemoglobin and myoglobin, consisting of

hema-. Prefix indicating relationship to blood.

reduced (ferrous) iron bound to protoporphyrin.

See porphyrin hemin.

hematein.

Use: Medical and biochemical research.

CAS: 475-25-2. C

. A tetracyclic compound.

An oxidation product of hematoxylin, the coloring

hemel. (generic name for hexamethylmela-

principle of logwood. Not to be confused with he-

mine; HMM). C

[N(CH

)

]

(cyclic).

matin.

Properties: Solid. Insoluble in water; soluble in ace-

Properties: Dark-purple solid. Mp 200+C. Almost

tone.

insoluble in water, slightly soluble in alcohol and

Use: Chemosterilant for insects.

ether; soluble in dilute sodium hydroxide, giving a

bright-red color; soluble in ammonia with brown-

hemellitic acid. (2,3-xylic acid).

ish-violet color.

(CH

)

COOH.

Derivation: By adding ammonia to logwood extract

Properties: Mp 144C.

and exposing to air.

Use: Indicator, biological stain.

hemi-. Prefix meaning half.

hematin. C

FeOH. The hydroxide of

heme. Not to be confused with hematein.

hemicellulose. Cellulose having a degree of po-

Properties: Blue to brown-black powder. Decom-

lymerization of 150 or less. A collective term for ␣

poses at 200C without melting. Soluble in alkalies,

and ␥ cellulose. It is that portion of holocellulose

hot alcohol, or ammonia; slightly soluble in hot

that is soluble in mild caustic solution. The pure

pyridine; insoluble in water, ether, and chloroform.

form is obtained from corn grain hulls. It is not an

Derivation: By dissolving hemin in dilute potassium

important component of cellulosic products and is of

hydroxide, precipitating with acetic acid, and re-

chiefly theoretical interest. Hemicellulose obtained

crystallizing from pyridine.

by treating a mixture of hard and softwoods with

Use: Biochemical research.

steam has been used as an animal feed supplement.

hematite, red. (red iron ore; bloodstone; iron

hemicholinium.

oxide).

CAS: 16478-59-4. mf: C

CAS: 1317-60-8. Fe

with impurities.

Hazard: A poison by ingestion.

Properties: Brilliant black to blackish-red or brick-

red mineral with brown to cherry-red streak and

hemiketal. Organic compound formed by the

metallic to dull luster. D 4.9–5.3, Mohs hardness 6.

reaction of one molecule of ketone (RR

′

CO) with

Noncombustible.

one molecule of alcohol (R

′′

CO). Hemiketals are the

Hazard: A carcinogen (OSHA).

rings of ketose sugars.

Use: The most important ore of iron. Also certain

See ketals.

varieties are used as paint pigments and for rouge.

See iron oxide reds; ferric oxide.

hemimellitene. (1,2,3-trimethylbenzene).

(CH

)

hemato-. Prefix indicating relationship to blood.

Properties: Liquid. D 0.8944 (20/4C), fp −25.5C, bp

176C. Insoluble in water; soluble in alcohol. Occurs

hematoporphyrin.

in some petroleums.

CAS: 14459-29-1. C

. Deep-red crystals;

Hazard: Combustible. TLV: 25 ppm.

soluble in alcohol, sparingly soluble in ether; insolu-

Use: Raw material for chemical synthesis.

ble in water.

Derivation: Obtained from hemin or hematin by the

action of strong acids.

hemin. (Teichmann’s crystals; the chloride of

Hazard: Toxic. Reported to be preferentially ab- heme). C

FeCl.

δHHb

COOH

637 HENNA

hempa. (generic name for hexamethylphos-

phoric triamide; hexamethylphosphoramide;

HMPA; hexametapol).

CAS: 680-31-9. [N(CH

)

]

PO.

Properties: Water-white liquid; mild amine odor. Bp

230–232C (739.4 mm Hg), d 1.021 (15.5/15.5C).

Soluble in water and polar and nonpolar solvents.

Hazard: TLV: animal carcinogen. Toxic by skin

contact. Combustible.

Use: UV inhibitor in polyvinyl chloride, chemosteri-

lant for insects, promoting stereospecific reactions,

specialty solvent.

hempseed oil.

Properties: A drying oil similar in properties and

uses to linseed. Edible, iodine value approximately

Properties: Crystals that are brown by transmitted

160, d 0.923, refr index 1.470–1.472. Contains ap-

light and steel blue by reflected light. Sinters at

proximately 10% saturated fatty acids (palmitic and

240C. Freely soluble in ammonia water; soluble in

stearic), unsaturated acids present are linoleic, lin-

strong organic bases; insoluble in carbonate solu-

olenic, and oleic. Saponification value 190−193.

tions, dilute acid solutions; insoluble but stable in

Source: Produced chiefly in the former U.S.S.R.,

water.

southern Europe, Japan, Chile, little in U.S.

Derivation: By heating hemoglobin with acetic acid

Hazard: Combustible.

and sodium chloride.

Use: Identification of blood stains, biochemical re-

henda- compounds. See unde-.

search, complexing agent.

See chelate.

Henderson-Hasselbalch equation. An

equation relating the pH, the pKa, and the ratio of the

hemizygous. Having only one copy of a particu-

concentrations of the proton-acceptor (A-) and pro-

lar gene. For example, in humans, males are hemizy-

ton-donor (HA) species in a solution.

gous for genes found on the Y chromosome.

n-heneicosanoic acid. CH

(CH

)

COOH. A

hemo-. (haemo-, hem-, hema-, hemato-). Pre-

saturated fatty acid not normally found in natural

fix indicating relationship to blood.

fats or waxes.

Properties: White, crystalline solid. Mp 74.3C. Syn-

hemoglobin. (Hb). The respiratory protein of

thetic product available for organic synthesis, 99%

the red blood cells, it transfers oxygen from the

purity.

lungs to the tissues and carbon dioxide from the

Hazard: Combustible.

tissues to the lungs. Its affinity for carbon monoxide

is greater than 200 times that for oxygen. Hemoglo-

(z)-6-1-heneicosen-11-one.

bin is a conjugated protein of molecular weight

CAS: 54844-65-4. mf: C

65,000, consisting of approximately 94% globin

Hazard: Low toxicity by ingestion and skin contact.

(protein portion) and 6% heme. Each molecule can

Source: Natural product.

combine with one molecule of oxygen to form oxy-

hemoglobin (HbO

). The iron (in the heme portion)

henequen.

must be in the reduced (ferrous) state to enable the

Properties: Hard, strong, reddish fibers obtained

hemoglobin to combine with oxygen. Oxyhemoglo-

from the leaves of Agave fourcroydes. It is similar to

bin is available commercially as a brownish-red

sisal but coarser and stiffer.

powder or crystals, soluble in water.

Available forms: Denier ranges from 300 to 500.

Use: Medicine, usually called hemoglobin.

Source: Mexico, Cuba.

Hazard: Combustible.

hemp. Soft, white fibers 3–6 ft long. It is coarser

Use: Binder twine, cordage.

than flax but stronger, more glossy, and more dura-

ble than cotton. Obtained from the stems of Canna-

Henkel reaction. Industrial-scale thermal rear-

bis sativa.

rangement or disproportionation of alkaline salts of

Source: Central Asia, Italy, the former U.S.S.R.,

aromatic acids to symmetrical diacids in the pres-

India, U.S.

ence of cadmium or other metallic salts.

Hazard: Combustible. May ignite spontaneously

when wet.

Use: Blended with cotton or flax in toweling and

henna. A coloring principle obtained from dried

heavy fabrics, twine, cordage, packing. leaves of certain tropical plants (North Africa,

See cannabis. India).

638“HENNIG PURIFIER”

Use: Commercial hair-dyeing preparations to give a

hepatocyte. The major cell type of liver tissue,

yellow-red color; medicine as an antifungal agent. which is parenchymal tissue. Liver also contains

fixed macrophages called Kupfer cells and other

cells.

“Hennig Purifier” [PPG]. TM for a prepara-

tion having a soda-ash base and other materials.

Produced as walnut-sized briquettes. Packed in 100-

hepatoxane. See hepasynthyl.

lb paper bags.

Use: Ladle addition to produce cleaner steel by aiding

“Hepsera Tabs” [Lapgap]. TM for tablets.

in removal of dissolved oxides and silicates and

Use: For antiviral treatment of chronic hepatitis B.

fluxing nonmetallic inclusions to slag.

heptabarbital. (5-[1-cyclohepten-1-yl]-5-ethyl-

Henry reaction. Formation of nitroalcohols by

barbituric acid; 5-ethyl-5-cycloheptenylbarbituric

an aldol-type condensation of nitroparaffins with

acid).

aldehydes in the presence of base (Henry) or by the

CAS: 509-86-4. C

condensation of sodium salts of acinitroparaffins

Properties: White, crystalline powder; odorless;

with the sodium bisulfite addition products of alde-

slightly bitter taste. Mp 174C. Very sparingly solu-

hydes in the presence of a trace of alkali or weak acid

ble in water; slightly soluble in alcohol; soluble in

(Kamlet). Widely used in sugar chemistry.

alkaline solutions. Forms water-soluble sodium,

magnesium, and calcium salts.

Henry’s law. When a liquid and a gas are in

Use: Medicine (sedative).

contact, the mass of the gas that dissolves in a given

See barbiturate.

quantity of liquid is proportional to the pressure of

the gas above the liquid. Thus, if air is kept in contact

heptachlor. (generic name for 1, 4, 5, 6, 7,

with water at standard atmospheric pressure, each

8, 8-heptachloro-3a,4,7,7a-tetrahydro-4,7-metha-

kg of water dissolves 0.017 g oxygen at 20C; if this

noindene. Generic).

pressure is halved (by doing the experiment at high

CAS: 76-44-8. C

altitude where the pressure is only 0.5 atm), the

Properties: White to light-tan, waxy solid. Mp

water dissolves only 0.0085 g oxygen. The law

95–96C, d 1.57–1.59. Insoluble in water; soluble in

holds true only for equilibrium conditions, i.e., when

xylene and alcohol.

enough time has elapsed so that the quantity of gas

Hazard: Toxic by ingestion, inhalation, and skin

dissolved is no longer changing.

absorption; use has been restricted and discontinued

except for termite control. TLV: 0.5 mg/m

; animal

hentriacontane. C

or CH

(CH

)

carcinogen.

Properties: Crystals. D 0.781 (68C), bp 302C (15

Use: Insecticide.

mm Hg), mp 68C.

Hazard: Combustible.

heptachlorepoxide. C

O. A degradation

product of heptachlor that also acts as an insecticide.

HEOD. See dieldrin.

See epoxyheptachlor.

heparin.

heptachlorotetrahydromethanoindene.

CAS: 9005-49-6. A complex organic acid (muco-

See heptachlor.

polysaccharide) present in mammalian tissues; a

strong inhibitor of blood coagulation; a dextrorota-

n-heptacosane. CH

(CH

)

tory polysaccharide built up from hexosamine and

Properties: Crystals. D 0.804, bp 270C (15 mm Hg),

hexuronic acid units containing sulfuric acid ester

mp 59.5C. Soluble in alcohol; insoluble in water.

groups. Precise chemical formula and structure unc-

Hazard: Combustible.

ertain; a formula of (C

)

and molecular

weight of 12,000 have been suggested for sodium

n-heptadecane. C

or CH

(CH

)

heparinate.

Properties: Leaflets, soluble in alcohol. D 0.778, bp

Properties: White or pale-colored amorphous pow-

303C, mp 22.5C. Insoluble in water.

der; nearly odorless; hygroscopic. Soluble in water;

Hazard: Combustible.

insoluble in alcohol, benzene, acetone, chloroform,

and ether; pH in 17% solution between 5.0 and 7.5.

Derivation: Animal livers or lungs.

n-heptadecanoic acid. (margaric acid).

Grade: USP.

CAS: 506-12-7. CH

(CH

)

COOH. A saturated fat-

Hazard: May cause internal bleeding.

ty acid not normally found in natural fats or waxes.

Use: Medicine (anticoagulant), biochemical re-

Properties: Colorless crystals. Mp 61C, d 0.8355

search, rodenticides.

(90.6/4C), bp 363.8C, 230.7C (16 mm Hg), refr

index 1.4324 (70C). Soluble in alcohol and ether;

hepasynthyl. insoluble in water.

CAS: 5634-42-4. mf: C

•C

. Available forms: 99% pure synthetic product.

Hazard: Moderately toxic by ingestion. Use: Organic synthesis.

639

-HEPTANOIC ACID

heptadecanol. Any saturated C

alcohol. heptalin acetate. See methylcyclohexanol ac-

Hazard: Combustible. etate.

See n-heptadecanol; 3,9-diethyl-6-tridecanol.

heptamethylene. See cycloheptane.

n-heptadecanol. C

OH.

Properties: Colorless liquid. D 0.8475 (20/20C), bp

heptamethylnonane. C

. Isomer of cetane

308.5C, vap press <0.01 mm Hg (20C), flash p 310F

(hexadecane). In 1964 it replaced ␣-methylna-

(154C), bulk d 7.1 lb/gal (20C). Slightly soluble in

phthalene as ignition standard for diesel fuels.

water.

Properties: Ignition value 15 on cetane-␣-methylna-

Grade: Technical.

phthalene scale.

Hazard: Combustible.

Hazard: Flammable, moderate fire risk.

Use: Organic synthesis, plasticizer, intermediates,

perfume fixatives, soaps and cosmetics, manufac-

heptanal. (heptaldehyde; enanthaldehyde; al-

ture of wetting agents and detergents.

dehyde C-7).

CAS: 111-71-7. C

CHO.

2-(8-heptadecenyl)-2-imidazoline-1-ethanol.

Properties: Oily, colorless liquid; penetrating, fruity

See amine 220.

odor; hygroscopic. D 0.814–0.819, refr index 1.42,

mp 43C, bp 153C. Soluble in three volumes of 60%

2-heptadecylglyoxalidine. (2-heptadecylimi-

alcohol, slightly soluble in water. Soluble in ether.

dazoline). C

or C

Derivation: Castor oil, from decomposition of the

Properties: Waxy solid. Mp 85C, bp 200C (2 mm

ricinoleic acid glyceride.

Hg). Slightly soluble in water; soluble in alcohol,

Hazard: Combustible.

benzene; hydrolyzes on standing to form N-2-ami-

Use: Manufacture of 1-heptanol, organic synthesis,

noethyl stearamide.

perfumery, pharmaceuticals, flavoring.

Derivation: By reacting stearic acid with ethylene

diamine.

n-heptane. (dipropylmethane).

Hazard: Combustible.

CAS: 142-82-5. CH

(CH

)

Use: Fungicide.

Properties: Volatile, colorless liquid. Fp −90.595C,

bp 98.428C, refr index 1.38764 (20C), d 0.68368

2-heptadecylglyoxalidine acetate. See

(20C), flash p 25F (−3.89C) (CC). Soluble in alco-

glyodin.

hol, ether, chloroform; insoluble in water; distilla-

tion range 93.3–98.9C; vap press 2.0 psi (a)(37.7C)

2-heptadecylimidazoline. See 2-heptadecyl-

(max). Color Saybolt +30 (min), maximum sulfur

glyoxalidine.

content 0.01 wt %, corrosive passes ASTM D

130–30 test, autoign temp 433F (222C).

2-heptadecyl-2-imidazoline acetate. See

Derivation: Fractional distillation of petroleum, pu-

glyodin.

rified by rectification.

Grade: Commercial, 99%, spectro, ASTM reference

heptafluorobutyric acid. (perfluorobutyric

fuel, research, 99.92 mole %.

acid). C

COOH.

Hazard: Toxic by inhalation. Flammable, dangerous

Properties: Colorless, hygroscopic liquid with sharp

fire risk. TLV: TWA 400 ppm; STEL 500 ppm.

odor. Bp 120C (735 mm Hg), fp −17.5C, d 1.641

Use: Standard for octane-rating determinations (pure

(25C), refr index 1.290 (25C), surface tension 15.8

normal heptane has zero octane number), anesthetic,

dynes/cm (30C). Miscible with water, acetone,

solvent, organic synthesis, preparation of laboratory

ether, and petroleum ether; soluble in benzene and

reagents.

carbon tetrachloride; insoluble in carbon disulfide

See octane number.

and mineral oil.

Derivation: By electrolysis of a solution of butyric

1,7-heptanedicarboxylic acid. See azelaic

acid in hydrogen fluoride.

acid.

Hazard: Irritant to tissue.

Use: Intermediate, surfactant, acidulant.

1,7-heptanedioic acid. See pimelic acid.

␥-heptalactone.

CAS: 105-21-5. mf: C

n-heptanoic acid. (enanthic acid; n-heptylic

Properties: Colorless, sltly oily liquid; coconut,

acid; heptoic acid).

sweet, malty, caramel odor. D: 0.997−1.004 @ 20°,

CAS: 111-14-8. CH

(CH

)

COOH.

refr index: 1.439−1.445. Misc in alc, fixed oils; very

Properties: Clear, oily liquid; unpleasant odor. D

sltly sol in water.

0.9181 (20/4C), fp 8C, bp 221.9C, refr index 1.4229.

Hazard: A skin irritant.

Soluble in alcohol and ether, insoluble in water.

Use: Food additive;.

Derivation: By oxidizing heptanal with potassium

permanganate in dilute sulfuric acid.

heptaldehyde. See heptanal. Hazard: Combustible.

6401-HEPTANOL

Use: Organic synthesis, production of special lubri-

1-heptyl acetate.

cants for aircraft and brake fluids. CAS: 112-06-1. C

OOCCH

. Liquid with fruity

odor.

Use: Artificial fruit essences.

1-heptanol. See heptyl alcohol.

heptyl alcohol. (1-heptanol; enanthyl alco-

2-heptanol. See methyl amyl carbinol.

hol).

CAS: 111-70-6. C

OH.

3-heptanol.

Properties: Colorless, fragrant liquid. Fp −34.6C, bp

CAS: 589-82-2. CH

CH(OH)C

175C, d 0.824 (20/4C), refr index 1.4233 (20C),

Properties: Liquid. D 0.8224 (20C), fp −70C, bp

flash p 170F (76.6C). Slightly soluble in water;

156.2C, flash p 140F (60C) (CC). Slightly soluble in

miscible with alcohol and ether.

water.

Derivation: From heptaldehyde by reduction.

Hazard: Toxic by ingestion. Moderate fire risk.

Hazard: Combustible.

Use: Flotation frother, solvent and diluent in organic

Use: Organic intermediate, solvent, cosmetic formu-

coatings, intermediates.

lations.

2-heptanone. See methyl-n-amyl ketone.

heptylamine. C

Properties: Colorless liquid. D 0.777 (20/4C), fp

−23C, bp 155C, flash p 140F (60C) (OC). Slightly

3-heptanone. See ethyl butyl ketone.

soluble in water; soluble in alcohol and ether.

Hazard: Combustible.

4-heptanone. See dipropyl ketone.

heptyl formate. HCOOC

heptanoyl chloride. CH

(CH

)

COCl.

Properties: Colorless liquid; fruity odor. Bp 176.7C,

Properties: Solid. Mw 148.63, bp 173C, d 0.960, fp

d 0.894 (0C).

58C.

Hazard: Combustible.

Hazard: Corrosive and a lachrymator.

Use: Artificial fruit essences.

1-heptene. (1-heptylene). CH

(CH

)

CH:CH

heptyl heptoate. C

OOCC

Properties: Colorless liquid. D 0.6968 (20/4C), bp

Properties: Colorless liquid; fruity odor. D 0.865

93.3C, fp −10C, flash p 32F (0C), refr index 1.3994

(19C), bp 273–274C (754 mm Hg).

(20C). Soluble in alcohol, acetone, ether, petroleum

Hazard: Combustible.

and coal tar solvents; insoluble in water.

Use: Artificial fruit essences.

Hazard: Flammable, dangerous fire risk.

Use: Organic synthesis.

n-heptyl p-hydroxybenzoate. See heptyl-

paraben.

2-heptene. (2-heptylene).

(CH

)

CH:CHCH

(cis and trans isomers).

n-heptylic acid. See heptanoic acid.

Properties: Colorless liquid. D (cis) 0.708, (trans)

0.704, (commercial) 0.7010–0.7050 (20/4C), bp

heptyl (4-(1-methylethyl)phenyl)methyl 3-

(trans) 98C, (cis) 98.5C, (commercial) 97–99C, refr

pyridinylcarbonimidodithioate.

index 1.406 (20C); flash p (commercial) 28F

CAS: 51308-74-8. mf: C

(−2.2C). Soluble in alcohol, acetone, ether, petrole-

Hazard: Moderately toxic by ingestion.

um, and coal tar solvents; insoluble in water.

Use: Agricultural chemical.

Hazard: Flammable, dangerous fire risk.

Use: Suggested as plant growth-retardant.

heptylparaben. mf: C

Properties: Small colorless crystals or white crystal-

3-heptene. (3-heptylene). C

CH:CHC

line powder; odorless, burning taste. Mp: 48−51°.

Properties: (Mixed cis and trans isomers) Colorless

Sol in alc, ether; very sltly sol in water.

liquid. Bp 95C, d 0.705 (15.5/15.5C), refr index

Use: Food additive.

1.405 (20C), flash p 21F (−6.1C).

Hazard: Flammable, dangerous fire risk.

heptyl pelargonate. C

OOCC

Use: Suggested as plant-growth retardant.

Properties: Liquid with pleasant odor. D 0.866

(15.5/15.5C), bp 300C, refr index 1.4360.

6-heptenoic acid, 7-(2-cyclopropyl-4-(4-

Hazard: Combustible.

fluorophenyl)-3-quinolinyl)-3,5-dihydroxy-

Use: Flavors and perfumes.

,calcium salt (2:1), (3r,5s,6e)-. See NK

104 (acid).

␣-heptyl-3,4,5-trimethoxyphenethylamine.

CAS: 67293-51-0. mf: C

heptoic acid. See heptanoic acid. Hazard: A poison.

641 HERZ REACTION; HERZ

herbicide. (weed killer). A pesticide, either or- “Herculon” [Aqualon]. TM for polypropyl-

ganic or inorganic, used to destroy unwanted vege- ene olefin fibers. Available in bulked continuous

tation, especially various types of weeds, grasses, and continuous multifilament yarns, staple, and un-

cut tow.

and woody plants. Until 1924 inorganics such as

Use: Apparel, home furnishings, and industrial appli-

sodium chlorate, sodium chloride, ammonium sul-

cations.

famate, arsenic, and boron compounds were used.

At that time the more specific organics were intro-

hereditary cancer. Cancer that occurs due to

duced, typified by 2,4-dichlorophenoxyacetic acid

the inheritance of an altered gene within a family.

(2,4-D). Herbicides may be of two major types: (1)

See sporadic cancer.

selective, such as 2,4-D, 2,4,5-T, phenols, carba-

mates and urea derivatives, permitting elimination

of weeds without injury to the crop, and (2) nonse-

hereditary mutation. A gene change in the

lective, comprising soil sterilants (sodium com- body’s reproductive cells (egg or sperm) that be-

pounds) and silvicides (ammonium sulfamate). The comes incorporated in the DNA of every cell in the

latter kill woody plants and trees. Some types act as body; also called germline mutation.

overstimulating growth hormones. Many herbicides

are highly toxic and should be handled and applied

heroin. See diacetylmorphine.

with care; use of chlorinated types may be restricted.

See defoliant.

herring oil. See fish oil.

herbifert.

Herschbach, Dudley R. (1932– ). Awarded

CAS: 39324-65-7. mf: C

S•C

ClN

the Nobel Prize in chemistry in 1986 for work re-

Hazard: Moderately toxic by ingestion. Low toxicity

porting that the energies of reactions of crossed

by skin contact. SO

, and Cl

−

molecular beams of isolated alkali metal atoms and

alkyl halide molecules appeared mostly as vibra-

“Herclor” [Aqualon]. TM for a group of spe-

tional excited states of products. This method of

cialty elastomers based on epichlorohydrin, claimed

studying all types of chemical reactions led to a

to have unique service performance properties.

more detailed knowledge of reaction processes.

Use: Automotive and aircraft parts, wire and cable

Doctorate awarded from Harvard in 1958.

coating, seals and gaskets, packings, hose, belting,

and coated fabrics. “Herclor H” is a homopolymer,

Hershko, Avram. (1937– ). Born in Karcag,

and “Herclor C” a copolymer with ethylene oxide;

Hungary, Hershko won the Nobel Prize for chemis-

both have high resistance to ozone, heat, solvents,

try in 2004 for his pioneering work concerning the

and chemical attack.

discovery of ubiquitin-mediated protein degrada-

tion. He received his M.D. in 1965 and his Ph.D in

“Hercoflex” [Aqualon]. TM for a series of

1969 from the Hadassah Faculty of Medicine of the

plasticizers. 600 High-boiling ester of pentaerythri-

Hebrew University of Jerusalem. He is currently a

tol and a saturated aliphatic acid. 707 High molecu-

Distinguished Professor at the Rappaport Family

lar weight polyol ester. 707A High molecular

Institute for Research in Medical Sciences at the

weight polyol ester.

Technion (Israel Institute of Technology) in Haifa

Use: High-temperature vinyl electrical insulation.

and Adjunct Professor of Pathology at New York

900 High molecular weight polyester.

University. In 2000 he received the Albert Lasker

Use: Plasticizer for polyvinyl acetate.

Award for Basic Medical Research.

“Hercolube” [Aqualon]. TM for synthetic lu-

Herzberg, Gerhard. (1904–1999). A German-

bricant base stocks. J15 Saturated aliphatic ester of

born physicist who won the Nobel Prize for chemis-

pentaerythritol for plasticizing vinylidene chloride.

try in 1971 for his work on the composition of

Derivation: Derived from pentaerythritol esters of

molecules. His research involved the spectroscopy

saturated fatty acids.

of atoms and molecules and their excitation behav-

ior. He became a Canadian citizen and was the direc-

“Hercolyn” D [Aqualon]. TM for a pale, vis- tor of the Division of Pure Physics of the National

cous liquid; the hydrogenated methyl ester of rosin. Research Council of Canada.

Use: Plasticizing resin.

Herzig-Meyer determination of N-alkyl

hercules trap. Water-measuring liquid trap groups. N-alkylamines are refluxed with hy-

used in aquametry when the material collected is driodic acid and the quaternary alkyl ammonium

heavier than water. iodides are pyrolyzed to split off alkyl iodide, which

is determined gravimetrically by conversion to sil-

ver iodide or titrated as iodate.

“Herculoid” [Aqualon]. TM for nitrocellu-

lose containing 10.9–11.2% nitrogen.

Hazard: See nitrocellulose.

Herz reaction; Herz compounds. Forma-

Use: Pyroxylin plastics. tion of o-aminothiophenols by heating aromatic

642HESPERIDIN

amines with excess sulfur monochloride. The first DNA molecules with similar or partially identical

products formed are thiazothionium halides known sequences. Sometimes from two unmanipulated

as Herz compounds. If the position next to the amino species, at other times a gene has been modified and

reintroduced.

group is unoccupied, chloride is substituted at this

position during the reaction.

heterogeneity. The production of identical or

similar phenotypes by different genetic mecha-

hesperidin.

nisms.

CAS: 520-26-3. C

. A natural bioflavonoid of

the flavanone group.

heterogeneous. (Latin “different kinds”). Any

Properties: Fine needles. Mp 258–262C. Soluble in

mixture or solution comprised of two or more sub-

dilute alkalies and pyridine.

stances regardless of whether they are uniformly

Derivation: Extraction from citrus fruit peel.

dispersed. Common examples are such diverse ma-

Use: Synthetic sweetener research.

terials as air (a mixture of 20% oxygen and 80%

nitrogen), milk, marble, paint, gasoline, blood and

Hess’s law. The heat evolved or absorbed in a

mayonnaise. In all such cases, the mixtures can be

chemical process is the same whether the process

separated mechanically into their components. “Ho-

takes place in one or in several steps; also known as

mogenized” milk is as heterogeneous as regular

the law of constant heat summation.

milk and the term is, strictly speaking, a misnomer.

See homogeneous; mixture.

hetastarch. A starch derivative containing 90%

amylopectin.

heterogeneous catalysis. See catalysis, het-

Use: Blood plasma volume expander.

erogeneous.

heteratisine. See 20-ethyl-6-␤,8-dihydroxy-1-

heteromolybdates. (heteropolymolybdates). A

␣-methoxy-4.

large group of complex molybdenum salts and acids

in which the anion contains oxygen atoms and from

heteratisine 6-benzoate.

2 to 18 hexavalent molybdenum atoms, as well as

CAS: 99759-48-5. mf: C

one or more other metal or nonmetal atoms (phos-

Hazard: A poison.

phorus, arsenic, iron, and tellurium). The latter are

Source: Natural product.

referred to as hetero atoms, and any of approximate-

ly 35 elements may be present in this manner. Exam-

heteroaromatic. See heterocyclic.

ple: Na

PMo

, sodium phospho-12-molybdate.

The molecular weights of these compounds range up

heteroazeotrope. Azeotropic mixture having

to 3000. The acids and most of the salts are very

more than one liquid phase in equilibrium with the

soluble in water, and the acids and some salts are

vapor phase at the boiling points.

soluble in organic solvents.

Use: Phosphomolybdates and phosphotungstates are

heterochromatin. Chromatin which is in a con-

used as precipitants for basic dyes to form lakes and

densed, less accessible state and thus frequently

toners. The phospho- and silicomolybdate groups

transcriptionally silent. However, some DNA is

are of key importance in the functioning of certain

constitutive heterochromatin (e.g. the second X

enzymes. There are many uses in analytical chem-

chromosome is inactivated to a Barr body for dosage

istry.

compensation) whereas other DNA is facultative

heterochromatin. An example might be genes re-

heterophos.

quired under time of stress only, or during a stage of

CAS: 40626-35-5. mf: C

PS.

the cell cycle.

Hazard: A poison by ingestion.

Use: Agricultural chemical.

heterocyclic. Designating a closed-ring struc-

ture, usually of either 5 or 6 members, in which one

heteropolysaccharide. A polysaccharide con-

or more of the atoms in the ring is an element other

taining two or more types of sugars.

than carbon, e.g., sulfur, nitrogen, etc. Examples are

pyridine, pyrole, furan, thiophene, and purine.

heterotroph. An organism that requires complex

nutrient molecules, such as glucose, as an energy

source.

heterotropic enzyme. An allosteric enzyme

requiring a molecule other than its substrate as a

modulator.

heteroduplex DNA. Duplex DNA containing heterozygosity. The presence of different alleles

complementary strands derived from two different at one or more loci on homologous chromosomes.

643 1,2,3,4,5,6-HEXACHLOROCYCLO

heterozygote. See heterozygosity. Hazard: Toxic by ingestion and inhalation, strong

irritant. Combustible. Evolves phosgene when

heated.

HETP. (1) Abbreviation for hexaethyl tetra-

Use: Desiccant, herbicide.

phosphate; (2) abbreviation for height equivalent to

a theoretical plate.

hexachlorobenzene. (perchlorobenzene).

See theoretical plate.

CAS: 118-74-1. C

Properties: White needles. D 2.04, mp 229C, bp

“Hetron” [Ashland]. TM for an unsaturated

326C, flash p 468F (242C). Soluble in benzene and

polyester resin.

boiling alcohol; insoluble in water.

Use: Corrosion and chemical resistance, fire-retar-

Hazard: TLV: 0.002 (skin); Animal Carcinogen.

dant, castings, marine gel coats, laminating, and

Toxic by ingestion. Combustible.

molding.

Use: Organic synthesis, fungicide for seeds, wood

preservative.

Heumann-Pfleger indigo synthesis. Cycli-

zation of phenylglycine to indoxyl followed by oxi-

2,2

′

,4,4

′

,6,6

′

-hexachlorobiphenyl.

dation by air or oxidizing agents, such as ferric

CAS: 33979-03-2. mf: C

chloride, to yield indigo.

Hazard: A poison.

heuristic. See computational chemistry.

2,3

′

,4,4

′

,6-hexachlorobiphenyl.

CAS: 59291-65-5. mf: C

Hevesy, Georg de. (1885–1966). A Hungarian

Hazard: A poison.

chemist who won the Nobel Prize in chemistry in

1943. He discovered the element hafnium in 1923.

One of his interesting projects involved the calcula-

hexachlorobutadiene.

tion of the percentages of chemical elements in the

CAS: 87-68-3. Cl

C:CClCCl:CCl

universe. He also was involved in research using

Properties: Clear, colorless liquid; mild odor. Freez-

radioactive lead and phosphorus traces. His work

ing range −19 to −22C, boiling range 210–220C, refr

included the separation of isotopes by physical

index 1.552 (20C), flash p none, d 1.675 (15.5/

means. His Ph.D. was granted at Freiburg in 1908.

15.5C), bulk d 13.97 lb/gal (15.5C), purity 98%

(min). Vap press 22 mm Hg (100C), 500 mm Hg

hexa-. Prefix signifying six.

(200C). Viscosity (37.7C) 2.447 cP, 1.479 centi-

stokes; (98.9C) 1.131 cP, 0.724 centistokes. Insolu-

hexabromobenzene.

ble in water, compatible with numerous resins, solu-

CAS: 87-82-1. mf: C

ble in alcohol and ether. Nonflammable.

Hazard: A poison.

Hazard: Toxic by ingestion and inhalation, a sus-

pected carcinogen. TLV: TWA 0.02 ppm; animal

hexabromoethane. C

. carcinogen.

Properties: Yellowish-white, rhombic needles. Use: Solvent for elastomers, heat-transfer liquid,

Slightly soluble in water and alcohol. Mp 149C transformer and hydraulic fluid, wash liquor for

(decomposes with separation of bromine). removing C

and higher hydrocarbons.

Derivation: Action of bromine on diiodoacetylene.

Use: Organic synthesis.

1,2,3,4,5,6-hexachlorocyclohexane. (BHC;

HCCH; HCH; TBH; benzene hexachloride).

1,2,3,4,6,7-hexabromonaphthalene.

CAS: 608-73-1. C

. A systemic insecticide.

CAS: 75625-24-0. mf: C

The ␥ isomer is known as lindane.

Hazard: A poison by ingestion.

Properties: White or yellowish powder or flakes;

musty odor. Melting point vary with isomeric com-

1,1,1,3,3,3-hexabutyldistannthiane.

position. D 1.87, vap press approximately 0.5 mm

CAS: 4808-30-4. mf: C

SSn

Hg (60C). Stable toward moderate heat but decom-

Properties: Colorless oil. Bp: 208° (decomp).

posed by alkaline substances. Mp of the pure iso-

Hazard: Moderately toxic by ingestion. TWA 0.1

mers are (␣-trans) 157–158C, (␤-cis) 297C (sub-

mg(Sn)/m

; STEL 0.2 mg/m

(skin)

limes), (␥) 112.5C, (⌬) 138–139C, (⑀) 217–219C.

Use: Drug.

Insoluble in water; soluble in 100% alcohol, chloro-

form, and ether.

hexacalcium phytate. See calcium phytate.

Derivation: Chlorination of benzene in actinic light.

Method of purification: Fractional crystallization.

hexachloroacetone. (hexachloro-2-propa- The technical grade may run 10–15% ␥ isomer but

none). can be brought up to 99% (lindane).

CAS: 116-16-5. Cl

CCOCCl

. Grade: Technical (mixture of isomers), 25% ␥ iso-

Properties: Yellow liquid. Bp 204C, fp −3C, d 1.744 mer, and 99% ␥ isomer (lindane).

(12/12C). Slightly soluble in water; soluble in ace- Hazard: Toxic by ingestion and inhalation, absorbed

tone. by skin, strong irritant to skin and eyes. CNS depres-

644HEXACHLOROCYCLOPENTADIENE

sant. Use may be restricted. TLV: (lindane) 0.5 mg/ irritant, absorbed by skin. TLV: 1 ppm; suspected

. human carcinogen.

Use: Component of insecticides; toxic to flies, cock- Use: Organic synthesis, retarding agent in fermenta-

roaches, aphids, grasshoppers, wire worms, and boll

tion, camphor substitute in nitrocellulose, pyrotech-

weevils.

nics and smoke devices, solvent, explosives.

hexachlorocyclopentadiene. (perchlorocy-

hexachloromethylcarbonate. (triphosgene).

clopentadiene).

(OCCl

)

CO.

CAS: 77-47-4. C

Properties: White crystals; odor similar to that of

Properties: Pale-yellow liquid; pungent odor. Bp

phosgene. D approximately 2, bp 205–206C (partial

239C, fp 9.6C, d 1.717 (15/15C), bulk d 14.30 lb/gal

decomposition), mp 78–79C. Decomposed by hot

(15.5C), refr index 1.563 (25C), flash p none. Non-

water and alkali hydroxides. Only slowly aceted

flammable.

upon by cold water. Soluble in alcohol, benzene,

Grade: Technical.

ether.

Hazard: Toxic by ingestion, inhalation, and skin

Derivation: Chlorination of dimethyl carbonate ex-

absorption. TLV: TWA 0.01 ppm; not classifiable as

posed to direct sunlight.

a human carcinogen.

Hazard: Strong irritant to eyes and skin.

Use: Intermediate for resins, dyes, pesticides, fungi-

Use: Lachrymator.

cides, pharmaceuticals.

hexachloromethyl ether. O(CCl

)

2,3,4,4,5,5-hexachloro-2-cyclopenten-1-one.

Properties: Liquid; phosgenelike odor. D 1.538

CAS: 2514-52-5. mf: C

(18C), bp 98C (partial decomposition).

Hazard: A poison by ingestion. Moderately toxic by

Derivation: Chlorination of dichloromethyl ether.

inhalation.

Hazard: Strong irritant to eyes and skin.

2,2

′

,4,4

′

,5,5

′

-hexachlorodiphenyl ether.

hexachloronaphthalene.

CAS: 71859-30-8. mf: C

CAS: 1335-87-1. C

Hazard: A reproductive hazard.

Properties: White solid.

Hazard: Toxic by inhalation, strong irritant, ab-

2,2

′

,4,4

′

,5,6

′

-hexachlorodiphenyl ether. sorbed by skin. TLV: 0.2 mg/m

CAS: 106220-81-9. mf: C

Hazard: A reproductive hazard.

1,2,3,4,6,7-hexachloronaphthalene.

CAS: 103426-96-6. mf: C

hexachlorodiphenyl oxide. (chlorinated di- Hazard: A reproductive hazard.

phenyl oxide).

CAS: 31242-93-0. C

1,2,3,5,6,7-hexachloronaphthalene.

Properties: Light-yellow, very viscous liquid. Bp

CAS: 103426-97-7. mf: C

230–260C (8 mm Hg), d 1.60 (20/20C), bulk d 13.12

Hazard: A poison by ingestion.

lb/gal (25C), refr index 1.621 (25C), flash p none.

Soluble in methanol, ether; very slightly soluble in

hexachlorophene. (2,2

′

-methylene-bis-(3,4,6-

water. Nonflammable.

trichlorophenol); bis-(3,5,6-trichloro-2-hydroxy-

Hazard: Toxic by ingestion. TLV: 0.5 mg/m

phenyl)methane).

Use: Solvent, intermediate.

CAS: 70-30-4. (C

HCl

OH)

Properties: White, free-flowing powder; odorless.

1,1,1,4,4,4-hexachloro-1,4-disilabutane.

Mp 161–167C. Soluble in acetone, alcohol, ether,

See bis(trichlorosilyl)ethane.

chloroform; insoluble in water.

Derivation: Condensation of 3,4,5-trichlorophenol

hexachloroendomethylene with formaldehyde in the presence of sulfuric acid.

tetrahydrophthalic acid. See chlorendic Hazard: FDA prohibits use unless prescribed by a

acid. physician.

Use: Topical antiinfective (restricted), germicidal

soaps, veterinary medicine.

hexachloroendomethylene

tetrahydrophthalic anhydride. See chlo-

rendic anhydride.

hexachloro-2-propane. See hexachloroace-

tone.

hexachloroethane. (perchloroethane; carbon

trichloride; carbon hexachloride).

hexachloropropylene. (hexachloropropene;

CAS: 67-72-1. Cl

CCCl

. perchloropropylene). CCl

CCl:CCl

Properties: Colorless crystals: camphorlike odor. D Properties: Water-white liquid. Bp 210C. Insoluble

2.091, mp 185C, bp sublimes at 185C. Soluble in in water; miscible with alcohol, ether, chlorinated

alcohol and ether; insoluble in water. compounds.

Hazard: Toxic by ingestion and inhalation, strong Use: Solvent, plasticizer, hydraulic fluid.

645 HEXAETHYLDISTANNOXANE

hexacontane. C

122

. High molecular weight hexadecyl mercaptan. See cetyl mercaptan.

hydrocarbon.

Properties: Waxy solid. Mp 101C.

tert-hexadecyl mercaptan. C

SH.

Hazard: Combustible.

Properties: Colorless liquid; unpleasant odor. Boil-

ing range 121–149C (5 mm Hg), d 0.874 (60/60F),

hexacosanoic acid. See cerotic acid.

refr index 1.474 (20C), flash p 265F (129.4C).

Hazard: Combustible.

n-hexadecane. (cetane). C

Use: Polymer modification.

Properties: Colorless liquid. D 0.77335 (20/4C),

See thiol.

flash p 200F (93C), bp 286.5C, mp 18.14C, refr

index 1.43435 (20C). Soluble in alcohol, acetone,

hexadecyltrichlorosilane.

ether; insoluble in water, autoign temp 401F (205C).

CAS: 5894-60-0. C

SiCl

Grade: Technical, ASTM.

Properties: Colorless to yellow liquid. Bp 269C, d

Hazard: Combustible.

0.996 (25/25C), refr index 1.4568 (25C), flash p

Use: Solvent, organic intermediate, ignition standard

295F (146C).

for diesel fuels.

Derivation: By Grignard reaction of silicon tetra-

See cetane number.

chloride and hexadecylmagnesium chloride.

Grade: Technical.

hexadecanoic acid. See palmitic acid.

Hazard: Strong irritant. Combustible. Evolves hy-

drogen chloride in the presence of moisture.

1-hexadecanol. See cetyl alcohol.

Use: Intermediate for silicones.

hexadecanoyl chloride. See palmitoyl chlo-

hexadecyltrimethylammonium bromide.

ride.

See cetyl trimethylammonium bromide.

(z)-7-hexadecenal.

hexadecyltrimethylammonium chloride.

CAS: 56797-40-1. mf: C

CAS: 112-02-7. mf: C

N•Cl.

Hazard: Low toxicity by ingestion.

Hazard: A poison by ingestion and skin contact.

Source: Natural product.

1,4-hexadiene.

(z)-9-hexadecenal.

CAS: 42296-74-2. H

C:CHCH

HC:CHCH

CAS: 56219-04-6. mf: C

Properties: Colorless liquid. D 0.6996 (20/4C), bp

Hazard: Low toxicity by ingestion.

64C (745 mm Hg), refr index 1.4162 (20C), flash p

Source: Natural product.

−6F (−21.1C). Insoluble in water.

Derivation: Reaction between ethylene and butadi-

1-hexadecene. (cetene; ␣-hexadecylene).

ene with a special catalyst.

(CH

)

CH:CH

Hazard: Highly flammable, explosive limits in air

Properties: Colorless liquid. Mp 4C, bp 274C, flash

2–6.1%.

p 200F (93C), d 0.784 (15/4C), refr index 1.441

Use: As third monomer in EPDM synthetic elas-

(20C). Insoluble in water; soluble in alcohol, ether,

tomers.

petroleum, and coal tar solvents.

Derivation: Treatment of cetyl alcohol with phos-

2,4-hexadienedial, (e,e)-.

phorus pentoxide.

CAS: 18409-46-6. mf: C

Grade: 95% purity.

Hazard: A poison.

Hazard: Combustible.

Use: Organic synthesis.

2,4-hexadienoic acid. See sorbic acid.

cis-9-hexadecenoic acid. See palmitoleic

1,5-hexadiyne. See dipropargyl.

acid.

hexa-2-ethylbutoxydisiloxane.

(z)-11-hexadecenol.

[(CH

CH(C

)CH

Si]

CAS: 56683-54-6. mf: C

Properties: Colorless oil. Bp 195C (0.2 mm Hg).

Hazard: Low toxicity by ingestion.

Derivation: Reaction of silicon tetrachloride, 2-

Source: Natural product.

ethylbutanol, and water.

Hazard: Combustible.

(z)-7-hexadecen-1-ol acetate.

Use: Aircraft hydraulic fluid.

CAS: 23192-42-9. mf: C

Hazard: Moderately toxic by ingestion and skin con-

tact. Low toxicity by inhalation.

hexaethyldistannoxane.

Use: Agricultural chemical.

CAS: 1112-63-6. mf: C

OSn

Properties: Air-sensitive liquid. D: 1.377 @ 20°, bp:

6-hexadecenolide. See ambrettolide. 272°.

646HEXAETHYLDISTANNTHIANE

Hazard: A poison. TWA 0.1 mg(Sn)/m

; STEL 0.2 Use: Dielectric and coolant, aerosol propellant, re-

mg/m

(skin) frigerant.

Use: Drug.

2-(1,1,2,3,3,3-hexafluoro-2-(heptafluoro-

propoxy)propoxy)-2,3,3,3-tetrafluoro-

hexaethyldistannthiane.

propanoic acid.

CAS: 994-50-3. mf: C

SSn

CAS: 13252-14-7. mf: C

Properties: A liquid. D: 1.431 @ 20°, bp: 187−188°

Hazard: Moderately toxic by inhalation and skin

@ 20 mm.

contact. A moderate eye irritant.

Hazard: A poison. TWA 0.1 mg(Sn)/m

; STEL 0.2

mg/m

(skin)

hexafluorophosphoric acid.

Use: Drug.

CAS: 16940-81-1. HPF

Properties: (65% solution) Colorless, fuming liquid.

hexaethyl tetraphosphate. (HETP).

D 1.81, mp 31C (6H

O). Stable in neutral and alka-

CAS: 757-58-4. A mixture of ethyl phosphates and

line solutions.

ethyl pyrophosphates (TEPP).

Hazard: Strong irritant to tissue.

Properties: Yellow liquid. D 1.26–1.28 (25/4C), fp

Use: Metal cleaners, electrolytic or chemical polish-

−90C, refr index 1.427, decomposes at high temper-

ing agents for the formation of protective coatings

atures. Soluble or miscible with water and many

for metal surfaces, and as a catalyst.

organic solvents except kerosene; hydrolyzes in low

concentration; hygroscopic.

1,1,1,2,3,3-hexafluoropropane.

Hazard: Toxic by ingestion, inhalation, and skin

CAS: 431-63-0. mf: C

absorption; cholinesterase inhibitor.

Hazard: Low toxicity by inhalation. A reproductive

Use: Contact insecticide.

hazard.

Note: Hexaethyl tetraphosphate and compressed gas

mixture not accepted by air or by passenger rail. For

1,1,1,3,3,3-hexafluoropropane.

details consult regulations.

CAS: 690-39-1. mf: C

Hazard: Moderately toxic by inhalation route.

hexafluoroacetone.

CAS: 684-16-2. CF

COCF

hexafluoropropylene. (perfluoropropene).

Properties: Colorless, hygroscopic, highly reactive

CF:CF

gas. Bp −27C, fp −122C, liquid density 1.33 (25C),

Properties: Gas. Fp −156C, bp −29C, d 1.583 (−40/

minimum purity 95%.

4C).

Hazard: Toxic by inhalation and skin absorption.

Reacts vigorously with water and other substances,

hexafluoropropylene epoxide. (HFPO).

releasing considerable heat. Nonflammable. TLV:

0.1 ppm.

Derivation: Oxidation of hexafluoropropylene with

Use: Intermediate in organic synthesis.

alkaline hydrogen peroxide at approximately −30C.

Use: Monomer for HFPO polymers that are heat

hexafluoroacetone bisphenol a.

resistant to 410C. Noncombustible.

CAS: 1478-61-1. mf: C

See “Freon E”; “Krytox.”

Hazard: Moderately toxic by ingestion.

hexafluorosilicic acid. See fluosilicic acid.

hexafluorobenzene. C

Properties: Liquid. Bp 80.26C, mp 5.2C, d 1.613.

hexaglycerol. See trimethylolpropane, poly-

Hazard: Toxic by inhalation. Combustible.

glycerol.

Use: Chemical intermediate, solvent in NMR spec-

troscopy.

hexahydric alcohol. See mannitol, sorbitol,

and dulcitol.

hexafluorocalcitriol.

CAS: 83805-11-2. mf: C

hexahydroaniline. See cyclohexylamine.

Hazard: A poison by ingestion.

hexahydrobenzene. See cyclohexane.

hexafluorodiphenylolpropane. See hexafl-

uoroacetone bisphenol a.

hexahydrobenzoic acid. (cyclohexanecar-

boxylic acid [a naphthenic acid]). C

COOH.

hexafluoroethane. (fluorocarbon 116). Properties: Colorless monoclinic prisms. Mp 31C,

CAS: 76-16-4. CF

. bp 233C, d 1.048 (15/4C), refr index 1.4561

Properties: A gas. Bp −78.2C, d 1.59. Insoluble in (33.8C). Slightly soluble in water; soluble in alcohol

water; slightly soluble in alcohol. One of the most and ether.

stable of all organic compounds. Use: Paint and varnish driers, dry-cleaning soaps,

Grade: 99.6% pure. lubricating oils, stabilizer for rubber.

647 HEXAMETHYLENEDIAMINE

hexahydrocresol. See methylcyclohexanol. hexametapol. See hempa.

hexamethonium chloride. (hexamethylene-

hexahydro-4,7-methanoindandimethanol.

bis(trimethylammonium) chloride).

See tricyclodecanedimethanol.

CAS: 60-25-3. (CH

)

NCl(CH

)

NCl(CH

)

Properties: White, crystalline, hygroscopic powder;

hexahydromethylphenol. See methylcyclo-

faint odor. Mp 289–292C (decomposes). Very solu-

hexanol.

ble in water; soluble in alcohol, methanol, and n-

propanol; insoluble in chloroform and ether. Avail-

hexahydrophenol. See cyclohexanol.

able commercially as unhydrated form or as

dihydrate.

hexahydrophthalic anhydride. (1,2-cyclo-

Use: Medicine (antihypertensive).

hexandicarboxylic anhydride). C

(CO)

Properties: Clear, colorless, viscous liquid that be-

hexamethylbenzene. C

or C

(CH

)

comes a glassy solid at 35–36C. Bp 158C (17 mm

Properties: Colorless plates. Bp 265C, mp 165.5C.

Hg), d 1.19 (40C). Miscible with benzene, toluene,

Soluble in alcohol; insoluble in water.

acetone, carbon tetrachloride, chloroform, ethanol,

Hazard: Combustible.

and ethyl acetate; slightly soluble in petroleum

ether.

hexamethylcyclotrisilazane.

Hazard: Toxic by inhalation, strong irritant to eyes

CAS: 1009-93-4. mf: C

and skin.

Hazard: Moderately toxic by ingestion.

Use: Intermediate for alkyds, plasticizers, insect re-

pellents, and rust inhibitors; hardener in epoxy

hexamethyldiaminoisopropanol diiodide.

resins.

See propiodal.

hexahydropyridine. See piperidine.

hexamethyldisilazane. (HMDS).

CAS: 999-97-3. (CH

)

SiNHSi(CH

)

hexahydrotoluene. See methylcyclohexane.

Properties: Liquid. D 0.77 (25C), refr index 1.4057

(25C), bp 125C, flash p 77F (25C). Soluble in ace-

hexahydro-1,3,5-trinitro-sym-triazine. See

tone, benzene, ethyl ether, heptane, perchloroethy-

cyclonite.

lene; reactive with methanol and water.

Grade: 99% min.

hexahydroxycyclohexane. See inositol.

Hazard: Flammable, moderate fire risk.

Use: Chemical intermediate, chromatographic

hexahydroxylene. See dimethylcyclohexane.

packings.

hexaisobutylditin.

hexamethyldistannane. See hexamethylditin.

CAS: 3750-18-3. mf: C

Hazard: A poison. TWA 0.1 mg(Sn)/m

; STEL 0.2

hexamethylditin.

mg/m

(skin)

CAS: 661-69-8. mf: C

Properties: Crystals from pet ether. Mp: 28°, bp:

hexakis(methoxymethyl)melamine.

182°.

Hazard: A poison by ingestion. TWA 0.1 mg(Sn)/

❘

C(NR)NC(NR)N

❘

C(NR) where R

(CH

OCH

)

; STEL 0.2 mg(Sn)/m

(skin).

Use: Crosslinking agent for alkyds, epoxies, cellulo-

Use: Agricultural chemical.

sics, and vinyls.

hexamethylene. See cyclohexane.

n-hexaldehyde. (caproic aldehyde).

CAS: 66-25-1. CH

(CH

)

CHO.

hexamethylenediamine. (1,6-diaminohexane;

Properties: Colorless liquid; sharp aldehyde odor. D

1,6-hexanediamine).

0.8156 (20/20C), bp 128.6C, vap press 10.5 mm Hg

CAS: 124-09-4. H

N(CH

)

(20C), flash p 90F (32.2C) (OC), bulk d 6.9 wt/gal

Properties: Colorless leaflets. Mp 39–42C, bp 205C.

(20C), fp −56.3C. Immiscible with water.

Soluble in water; slightly soluble in alcohol and

Grade: Technical.

benzene.

Hazard: Flammable, moderate fire risk.

Derivation: (1) Reaction of adipic acid and ammonia

Use: Organic synthesis of plasticizers, rubber chemi-

(catalytic vapor phase) to yield adiponitrile, fol-

cals, dyes, synthetic resins, insecticides.

lowed by liquid-phase catalytic hydrogenation. (2)

Chlorination of butadiene followed by reaction with

“Hexalin” [Du Pont]. TM for cyclohexanol sodium cyanide (cuprous chloride catalyst) to 1,4-

(usually shipped with 2.25% methanol as anti- dicyanobutylene and hydrogenation.

freeze). Hazard: Toxic by ingestion, strong irritant to tissue.

Hazard: Toxic by ingestion. TLV: 0.5 ppm. Combustible.

648HEXAMETHYLENEDIAMINE

Use: Formation of high polymers, e.g., nylon 66.

hexamethylphosphoramide. See hempa.

hexamethylphosphoric triamide. See

hexamethylenediamine carbamate. See

hempa.

“Diak.”

hexamethyltetracosahexaene. See squalene.

hexamethylene diisocyanate.

CAS: 822-06-0. OCN(CH

)

NCO.

hexamethyltetracosane. See squalane.

Properties: Liquid. D 1.04 (25/15.5C), flash p 284F

(140C).

hexamine. See hexamethylenetetramine.

Hazard: TLV: 0.005 ppm. Combustible.

Use: Chemical intermediate.

hexanaphthene. See cyclohexane.

hexamethylene glycol. (1,6-hexanediol).

n-hexane.

CAS: 629-11-8. CH

OH(CH

)

OH.

CAS: 110-54-3. CH

(CH

)

Properties: Crystalline needles. Mp 42C, bp 210C,

Properties: Colorless, volatile liquid; faint odor. D

refr index 1.457, d 0.953 (50C), flash p 130C (266F).

0.65937 (20/4), bp 68.742C, fp −95C, refr index

Derivation: Reduction of adipic acid ester with cop-

1.37486 (20C), flash p −9F (−22.7C), autoign temp

per chromite catalyst.

500F (260C). Soluble in alcohol, acetone, and ether;

Hazard: Toxic by ingestion.

insoluble in water.

Use: Solvent, intermediate for high polymers (nylon,

Derivation: By fractional distillation from petrole-

polyesters), coupling agent, coil coating.

um (molecular sieve process).

Grade: 85%, 95%, 99%, spectro, research, and nano-

hexamethyleneimine.

grade.

CAS: 111-49-9. C

NH (cyclic).

Hazard: Flammable, dangerous fire risk. TLV: 50

Properties: Clear, colorless liquid; ammonia-like

ppm.

odor. Bp 138C, fp −37C, d 0.8799 (20/4C).

Use: Solvent, especially for vegetable oils; low- tem-

Hazard: Toxic by ingestion, strong irritant to tissue.

perature thermometers; calibrations; polymeriza-

Use: Intermediate for pharmaceutical, agricultural,

tion reaction medium; paint diluent; alcohol denatu-

and rubber chemicals.

rant.

hexamethylenetetramine. (methenamine;

2-hexanecarboxylic acid.

HMTA; aminoform; hexamine, erroneously

CAS: 4536-23-6. mf: C

“Hexamethyleneamine”).

Hazard: A reproductive hazard.

CAS: 100-97-0. (CH

)

. A heterocyclic fused ring

structure.

hexanedioic acid. See adipic acid.

1,6-hexanediol. See hexamethylene glycol.

hexanedione-2,5. See acetonyl acetone.

1,2,6-hexanetriol.

Properties: White, crystalline powder or colorless

CAS: 106-69-4.

lustrous crystals; practically odorless. D 1.27 (25C);

HOCH

CH(OH)CH

OH.

soluble in water, alcohol, and chloroform; insoluble

Properties: Water-white liquid. D 1.1063, sets to

in ether; sublimes approximately 200C; partly de-

glass at approximately −20C (fp under controlled

composes.

conditions 32.8C), bp (178C) 5 mm Hg, flash p 380F

Derivation: Action of ammonia on formaldehyde.

(193C). Miscible with water.

Grade: Technical, NF (as methenamine).

Hazard: Combustible.

Hazard: Skin irritant. Flammable, dangerous fire

Use: Alkyd and polyester resin intermediate, soften-

risk.

er, moistening agent, and solvent.

Use: Curing of phenolformaldehyde and resorcinol-

formaldehyde resins, rubber-to-textile adhesives,

hexanitrodiphenylamine. (hexil; hexyl; hex-

protein modifier, organic synthesis, pharmaceuti-

ite; dipicrylamine). (NO

)

NHC

(NO

)

cals, ingredient of highly explosive cyclonite, fuel

Properties: Yellow solid. Mp 238–244C, decom-

tablets, rubber accelerator, fungicide, corrosion in-

poses violently at higher temperatures. Insoluble in

hibitor, shrink-proofing textiles, antibacterial.

water and alcohol; soluble in alkalies and warm

acetic or nitric acid.

hexamethylmelamine. See hemel.

Derivation: Nitration of diphenylamine, also from

dinitrochlorobenzene.

hexamethylpararosaniline chloride. See Hazard: Explodes on shock or exposure to heat,

methyl violet. dangerous.

649 HEXESTROL

Use: Booster explosive, analysis for potassium.

“Hexaphos” [FMC]. TM for a glassy phos-

phate of high molecular weight having superior wa-

hexanitrodiphenyl sulfide. (dipicryl sul- ter-softening properties.

fide). [(NO

)

]

S. Use: Water-softening, boiler-scale control, compo-

nent of cleansers, laundry mixes, dishwashing com-

Properties: Golden-yellow leaflets. Mp 234C. Spar-

pounds, pitch control in pulp industry, prevention of

ingly soluble in alcohol and ether; more soluble in

lime soap deposits in textile operations.

glacial acetic acid and acetone.

Derivation: Interaction of picryl chloride and sodi-

um thiosulfate in alcohol solution in the presence of

hexapropyldistannthiane.

magnesium carbonate.

CAS: 7328-05-4. mf: C

SSn

Hazard: Explodes on shock or exposure to heat;

Hazard: A poison. TWA 0.1 mg(Sn)/m

; STEL 0.2

dangerous.

mg/m

(skin)

Use: High explosive.

Use: Drug.

hexanitromannite. See mannitol hexanitrate.

hexatriacontane. C

Properties: Waxy solid. D 0.797, mp 75C.

hexaoctyldistannoxane. See 1,1,1,3,3,3-hex-

Hazard: Combustible.

aoctyldistannoxane.

See paraffin wax.

1,1,1,3,3,3-hexaoctyldistannoxane.

1-hexene. (hexylene).

CAS: 2787-93-1. mf: C

102

OSn

CAS: 592-41-6. CH

CH:CH

Hazard: Moderately toxic. TWA 0.1 mg(Sn)/m

;

Properties: Colorless liquid. D 0.6734 (20/4C), bp

STEL 0.2 mg/m

(skin)

63.55C, fp −139.8C, refr index 1.3876 (20C), flash p

Use: Drug.

−15F (−26.1C). Insoluble in water; soluble in al-

cohol.

hexaoctyldistannthiane.

Grade: 95%, 99%, research.

CAS: 13413-18-8. mf: C

102

SSn

Hazard: Irritant. Highly flammable, dangerous fire

Hazard: Moderately toxic. TWA 0.1 mg(Sn)/m

;

risk.

STEL 0.2 mg/m

(skin)

Use: Synthesis of flavors, perfumes, dyes, resins;

Use: Drug.

polymer modifier.

hexanoic acid. Legal label name for caproic

2-hexene. CH

CH:CHCH

acid.

Properties: (Mixed cis and trans isomers.) Colorless

liquid. Bp 68C, fp −146C, refr index 1.3948 (20C), d

1-hexanol. See hexyl alcohol.

0.686 (15.5/15.5C), flash p −5F (20.5C). Insoluble

in water; soluble in alcohol.

2-hexanone. See methyl-n-butyl ketone.

Grade: 95%, 99%.

Hazard: Highly flammable, dangerous fire risk.

3-hexanone. (ethyl propyl ketone).

Use: Chemical intermediate.

CAS: 589-38-8. C

CO(CH

)

Properties: Colorless liquid. Bp 124C, d 0.813

5-hexene-2-one. See allylacetone.

(22C), flash p 95F (35C) (OC).

Hazard: Toxic by ingestion and inhalation, strong

hexenol. (3-hexen-1-ol; leaf alcohol).

irritant. Flammable, moderate fire risk.

OH.

Use: Solvent.

Properties: Liquid; odor of green leaves. Bp. 156C,

refr index 1.438, d 0.85.

n-(n-hexanoyl)aniline.

Occurrence: Grasses, leaves, herbs, tea, etc.

CAS: 621-15-8. mf: C

NO.

Hazard: Combustible.

Hazard: Moderately toxic by ingestion.

Use: Odorant in perfumery.

hexanoyl chloride. CH

(CH

)

COCl.

Properties: Colorless liquid. Bp 151–153C, refr in-

hexestrol. (p,p

′

-(1,2-diethylethylene)diphenol).

dex 1.4867 (20C). Decomposed by water and alco-

CAS: 84-16-2.

hol; soluble in ether and chloroform.

HOC

CH(C

)CH(C

OH. A nonsteroid,

Hazard: Combustible.

synthetic estrogen.

Use: Chemical intermediate.

Properties: Odorless, white, crystalline powder; mp

185–188C; soluble in ether, acetone, alcohol, and

hexaphenyldisilane. [(C

)

Si]

. methanol; practically insoluble in water; sensitive to

Properties: White powder, mp 352C. light.

Derivation: Sodium condensation of triphenylchlo- Derivation: From anethole, by reaction of diacetyl

rosilane. peroxide on p-methoxy-n-propylbenzene.

Use: High-temperature applications. Use: Medicine (estrogenic hormone).

650HEXETIDINE

hexetidine. (amino-1,3-bis[␤-ethylhexyl]-5-me- Properties: Colorless liquid. D 0.8186, fp −51.6C,

thylhexahydropyrimidine). C

. bp 157.2C, bulk d 6.8 lb/gal (20C), refr index 1.1469

Properties: Liquid. D 0.860–0.875 (25/25C), bp (25C), flash p 149F (65C) (TOC), autoign temp

559F (292C). Slightly soluble in water; soluble in

172–176C (1 mm Hg), refr index 1.460–1.466

alcohol and ether.

(25C). Soluble in methanol, benzene, petroleum

Derivation: (1) By reduction of ethyl caproate, (2)

ether; insoluble in water.

from olefins by the Oxo process.

Grade: Technical, NF.

Grade: Technical (90–99%), purified (99.8%).

Hazard: Combustible.

Use: Fungicide, bactericide, algicide, antistatic agent

Use: Pharmaceuticals (introduction of hexyl group

for synthetics, insect repellent, medicine (antifungal

into hyponotics, antiseptics, perfume esters, etc.),

agent).

solvent, plasticizer, intermediate for textile and

leather finishing agents.

hexil. See hexanitrodiphenyl amine.

n-hexylamine.

hexite. See hexanitrodiphenyl amine.

CAS: 111-26-2. CH

(CH

)

Properties: Water-white liquid; amine odor. Boiling

hexobarbital. (n-methyl-5-cyclohexenyl-5-me-

range 126–132C, fp −21C, d 0.767 (20/20C), refr

thylbarbituric acid).

index 1.419 (20C), flash p 85F (29.4C) (OC). Slight-

CAS: 56-29-1. C

ly soluble in water.

Properties: White crystals. Mp 145–147C.

Hazard: Toxic by ingestion, inhalation, and skin

Use: Medicine (sedative).

absorption. Flammable, moderate fire risk.

See barbiturate.

n-hexyl bromide. (1-bromohexane).

“Hexogen Octoate” [AKZO]. TM for a se-

(CH

)

Br.

ries of paint driers made with odorless solvents,

Properties: Colorless to slightly yellow liquid. D

essentially solutions of metallic salts of 3-ethylhex-

1.165 (20/20C), bp 155.5C. Soluble in alcohol, es-

oic acid.

ters, ethers; insoluble in water.

Available forms: Supplied in a variety of high metal

Grade: 96–98% pure.

concentrations including calcium 4%, calcium 5%,

Use: Intermediate, for introduction of hexyl group.

cobalt 6%, lead 24%, manganese 6%, iron 6%, and

zinc 8%.

hexyl-2-butenoate.

CAS: 19089-92-0. mf: C

hexoic acid. See caproic acid.

Properties: Colorless liquid; fruity odor. D: 0.880,

refr index: 1.428−1.449. Sol in alc, fixed oils; insol

hexokinase. An enzyme that catalyzes the forma-

in water, propylene glycol.

tion of adenosine diphosphate and hexose-6-phos-

Hazard: Low toxicity by ingestion and skin contact.

phate from adenosine triphosphate and glucose or

A skin irritant.

fructose.

Use: Food additive.

Use: Biochemical research.

n-hexyl 2-butenoate. See hexyl-2-butenoate.

hexone. See methyl isobutyl ketone.

n-hexyl “Carbitol” [Dow]. TM for diethyl-

hexose. Aldehyde or ketone sugar containing six

ene glycol monohexyl ether.

carbons.

n-hexyl “Cellosolve” [Dow]. TM for ethyl-

hexyl. (1) The straight-chain group C

; (2)

ene glycol monohexyl ether.

Hexanitrodiphenylamine.

hexyl cinnamaldehyde.

hexyl acetate.

CAS: 101-86-0. C

C(CHO):CHC

CAS: 142-92-7. CH

COOC

Properties: Pale-yellow liquid; jasminelike odor,

Properties: Colorless liquid; sweet ester odor. Bp

particularly on dilution. D 0.953–0.959 (25C), refr

169.2C, d 0.890. Insoluble in water; very soluble in

index 1.5480–1.5520 (20C). Soluble in most fixed

alcohol and ether.

oils and in mineral oil; insoluble in glycerol and in

Derivation: From primary and sec-hexyl alcohols.

propylene glycol.

Hazard: Combustible.

Grade: FCC.

Use: Solvent for cellulose esters and other resins,

Hazard: Combustible.

spray base.

Use: Flavoring agent.

sec-hexyl acetate. See methyl amyl acetate.

hexyl crotonate. See hexyl-2-butenoate.

hexyl alcohol. (1-hexanol; amyl carbinol).

CAS: 111-27-3. CH

(CH

)

OH. hexylene. See 1-hexene.

651 HFPO

hexylene glycol. (4-methyl-2,4-pentanediol). p-tert-hexylphenol. C

OH.

Properties: Water-white liquid; faint phenol odor. D

CAS: 107-41-5. (CH

)

COHCH

OCH

0.986 (20/20C), boiling range 155–165C, refr index

Properties: Colorless liquid; nearly odorless. D

1.520 (20C), flash p 285F (140C).

0.9216 (20/4C), bp 198.3C, refr index 1.4276 (20C),

Hazard: Combustible.

flash p 200F (OC) (93C); bulk d 7.69 lb/gal. Misci-

Use: Organic synthesis, preparation of resinous con-

ble with water; hydrocarbons, and fatty acids.

densation products.

Hazard: Toxic by ingestion and inhalation; irritant to

skin, eyes, and mucous membranes. TLV: ceiling 25

hexylresorcinol. (1,3-dihydroxy-4-hexylben-

ppm. Combustible.

zene).

Use: Hydraulic brake fluids, printing inks, coupling

CAS: 136-77-6. C

(OH)

agent and penetrant for textiles, fuel and lubricant

additive, emulsifying agent, inhibitor of ice forma-

tion in carburetors, cosmetics.

See 1,6-hexanediol.

n-hexyl ether.

CAS: 112-58-3. C

Properties: Colorless liquid; characteristic odor. D

Properties: Yellow, viscous liquid that solidifies on

0.7942 (20/20C), bulk d 6.6 lb/gal (20C), fp −43.0C,

standing, or needle-shaped crystals; faint fatty odor;

viscosity 1.68 cP (20C), flash p 170F (76.6C), aut-

astringent taste. Mp 62–67C, bp 333C. Slightly sol-

oign temp 369F (187C). Very slightly soluble in

uble in water; freely soluble in alcohol, glycerol, and

water.

vegetable oils.

Hazard: Combustible.

Grade: NF.

Use: Extraction processes, manufacture of collodion,

Hazard: Irritant to respiratory tract and skin, concen-

photographic film, and smokeless powder.

trated solutions are vesicant.

Use: Medicine (topical antiseptic).

hexylic acid. See caproic acid.

hexyltrichlorosilane. C

SiCl

Properties: Colorless liquid; sharp penetrating odor.

hexyl isovalerate. mf: C

Fumes strongly in moist air.

Properties: Colorless liquid; pungent, fruity odor. D:

Hazard: Toxic by ingestion and inhalation, strong

0.853, refr index: 1.417. Sol in alc, fixed oils; insol

irritant. Combustible.

in water.

Use: Chemical intermediate.

Use: Food additive.

1-hexyne. (butyl acetylene). C

C≡CH.

hexyl mercaptan. C

SH.

Properties: Water-white liquid; characteristic odor.

Properties: Colorless liquid; unpleasant odor. Bp

D 0.7152 (20/4C), refr index 1.3990 (20C), bp

149–150C (768 mm Hg), d 0.8450 (20/4C), refr

71.4C, fp −132C.

index 1.4492 (20C).

Hazard: Probably flammable.

Grade: 95% min purity.

Hazard: Combustible.

hexynol. (1-hexyn-3-ol).

Use: Intermediate, synthetic rubber processing.

(CH

)

OC≡CH.

See thiol.

Properties: Light-yellow liquid; strong odor. Bp

142C, d 0.882 (20/20C). Slightly soluble in water;

hexyl methacrylate. C

OOCC(CH

):CH

miscible with most hydrocarbons, chlorinated sol-

Properties: Liquid. D 0.88, bp 67–85C (8 mm Hg).

vents, ketones, alcohols, and glycols.

Hazard: Combustible.

Hazard: Toxic by ingestion and inhalation, absorbed

Use: Monomer for plastics, molding powder, solvent

by skin. Probably flammable.

coatings, adhesives, oil additives; emulsions for tex-

Use: Corrosion inhibitor against mineral acids, high-

tile, leather, and paper finishing.

temperature oil-well-acidizing inhibitor.

2-(2-(2-(hexyloxy)ethoxy)ethoxy)ethanol.

Heyrovsky, Jaroslav. (1890–1967). A Cze-

CAS: 25961-89-1. mf: C

choslovakian physiochemist who won the Nobel

Hazard: A poison by ingestion.

Prize for chemistry in 1959. He is known for work in

Use: Agricultural chemical.

electrochemistry. He developed polarographic and

oscillo-polarographic methods. Although his Ph.D.

((hexyloxy)sulfinyl)methylcarbamic acid- was from the University of Prague, he later studied

2,3-dihydro-2,2-dimethyl-7-benzofuranyl in London.

ester.

CAS: 77248-43-2. mf: C

S. Hf. Symbol for hafnium.

Hazard: A poison by ingestion.

Use: Agricultural chemical.

HFPO. See hexafluoropropylene epoxide.

652HFG

HFG. See glucagon. sylvania. After studying abroad under Nernst and

van’t Hoff, he became professor of Chemistry at the

Hg. Symbol for mercury (Latin: hydrargyrum). University of California, Berkeley, in 1913 where he

remained until retirement. He made many important

contributions to physical chemistry, particularly in

HGP. Human Genome Project.

the area of nonelectrolyte solutions; his treatise on

this subject is a recognized classic and his textbook

“HGR” [Dow]. TM for an ion exchange resin

on the principles of chemistry established a new

used in water-treating and chemical process applica-

standard of excellence. He also made important con-

tions, strong acid cation exchange resin, 10% divin-

tributions to the thermodynamics of vaporization of

ylbenzene cross-linked.

liquids. He proposed the use of helium in deep-sea

diving equipment, which has become accepted prac-

HHDN. Abbreviation for hexa-

tice. A gifted teacher and lecturer, he continued his

chlorohexahydrodimethanonaphthalene.

constructive research to the end of his long life. He

See aldrin.

was unusually active in outdoor sports such as

swimming, skiing, and hiking. Among his numerous

HHMI. Howard Hughes Medical Institute.

awards were the Nichols and William Gibbs medals

and the Priestley medal.

hidden maximum system. See peritectic

system.

hindered isocyanate. See isocyanate gener-

ator.

hiding power. See opacity.

hindrance. See steric hindrance.

hi-flash naphtha. See naphtha (2a).

Hinsberg oxindole synthesis. Formation of

high-energy compound. A compound that on

oxindoles from secondary aryl amines and sodium

hydrolysis undergoes a large decrease in free energy

bisulfite addition compound of glyoxal; primary

under standard conditions.

aryl amines give glycine or glycinamide derivatives.

high-fructose corn syrup.

Hinsberg reaction. Reaction of primary and

Properties: Water-white to light yellow viscous liq-

secondary amines with sulfonyl halides to give sul-

uid; sweet taste. Misc with water.

fonamides; because the products from primary

Use: Food additive.

amines are soluble in alkali and those from secon-

dary amines are not, and since tertiary amines do not

highly conserved sequence. DNA sequence

react, this method is useful for the separation and

that is very similar across several different types of

identification of amines.

organisms.

See gene; mutation.

Hinsberg sulfone synthesis. Formation of

sulfonylquinol derivatives by addition of quinones

high-performance liquid chromatography.

to cold, dilute aqueous solutions of sulfinic acids.

(HPLC). A type of chromatography using rela-

tively high pressures and small diameter column

Hinsberg synthesis of thiophene

packings to achieve sharp and highly reproducible

derivatives. Formation of thiophene carboxyl-

elution profiles. Used to be called high pressure

ic acids from ␣-diketones and dialkyl thiodiacetate.

liquid chromatography.

high polymer. See polymer, high. Hinshelwood, Sir Cyril N. (1897–1968). An

English chemist who won the Nobel Prize for chem-

istry in 1956 along with Semenov, a Russian. He

high-throughput sequencing. A fast method

authored “The Kinetics of Chemical Change,” “The

of determining the order of bases in DNA.

Structure of Physical Chemistry,” and many other

See sequencing.

journal articles. His work clarified inorganic and

organic reactions. He was educated at Oxford before

high vacuum distillation. See molecular

he began lecturing and research.

distillation.

“Hippuran” [Mallinckrodt]. TM for brand of

Hilbert-Johnson reaction. Reaction of 2,4-

iodohippurate sodium, a water-soluble X-ray con-

dialkoxypyrimidines with halogenoses to yield py-

trast medium.

rimidine nucleosides.

Hildebrand, Joel. (1891–1983). One of the hippuric acid. (benzaminoacetic acid; ben-

most distinguished American chemists and teachers. zoylaminoacetic acid; benzoylglycocoll; ben-

Born in New Jersey, he obtained his doctorate in zoylglycin).

chemistry and physics from the University of Penn- CAS: 495-69-2. C

CONHCH

COOH.

653 HNRNA

Properties: Colorless crystals. D 1.371 (20C), mp powder; sltly bitter taste. Decomp 250°. Sol in water;

188C, decomposes on further heating. Soluble in hot

insol in alc, ether.

water, alcohol, and ether.

Use: Food additive.

Use: Organic synthesis and medicine.

histochemistry. A branch of biochemistry de-

His. Abbreviation for histidine.

voted to the study of the chemical composition and

structure of animal and plant tissues. It involves the

“Hi-Sil” [PPG]. TM for a group of hydrated,

use of microscopic, X-ray diffraction, and radioac-

amorphous silicas used as reinforcing pigments in

tive tracer techniques in examining the cellular com-

elastomers, as fillers and brightening agents in paper

position and structure of bones, blood, muscle, and

and paints, and as flow conditioners.

other animal and vegetable tissues. It is also applied

Use: In adhesives, caulks, and sealants.

to study of the action of herbicides, defoliants, etc.

See cytochemistry.

histaminase. An enzyme occurring in the animal

digestive system; it converts histidine to histamine.

histone. The family of five basic proteins (H1,

H2A, H2B, H3, and H4) that associate tightly with

histamine. (4-aminoethylglyoxaline; 4-(2-ami-

DNA in the chromosomes of all eukaryotic cells.

noethyl)imidazole; 4-imidazole ethylamine).

They contain varying amounts of the amino acids

CAS: 51-45-6. NH

lysine, arginine, cysteine, and glycine.

history, chemistry. See Appendix II A−E.

“HiTEC” Antioxidants [Albemarle]. TM

for a series of gasoline antioxidants based on phe-

nols (chiefly di-tert-butyl phenol). They inhibit for-

mation of gum and peroxides in gasoline and the

Properties: White crystals. Mp 83–84C, bp

formation of decomposed products of jet fuels in

209–210C (18 mm Hg). Soluble in water; slightly

storage. Also used for steam-turbine and industrial

soluble in alcohol. A product of the degradation of

oils and to retard decomposition of antiknock com-

histidine, histamine occurs in animal and human

pounds in gasoline.

body tissues and is liberated by injury to the tissue or

whenever a protein is decomposed by putrefactive

“Hitec” [Du Pont]. TM for a eutectic mixture

bacteria.

composed of sodium nitrite, sodium nitrate, and

Use: (As hydrochloride or phosphate) Medicine

potassium nitrate.

(diagnostic aid).

Use: Heat-transfer medium for both heating and cool-

See antihistamine.

ing operations in the range of 149–537C, such as

maintaining reactor temperature, high-temperature

histidine. (␣-amino-␤-imidazolepropionic

distillation, and preheating of reactants.

acid).

CAS: 71-00-1. HOOCCH(NH

)CH

.An

HMAF. See 6-(hydroxymethyl)acylfulvene.

amino acid essential for rats. It is found naturally in

the L(−) form.

HMDS. Abbreviation for hexamethyldisilazane.

HMF black. Abbreviation for high-modulus

furnace black.

See carbon black.

HMM. Abbreviation for hexamethylmelamine.

Properties: Colorless crystals.

DL-histidine, mp

See hemel.

285–286C with decomposition;

D(+)-histidine, mp

287–288C;

L(−)-histidine, mp 277C with decompo-

HMPA. Abbreviation for hexamethylphospho-

sition. Soluble in water; insoluble in alcohol and

ramide.

ether. Shows optical activity. Available commer-

See hempa.

cially as

L(+)-histidine hydrochloride and as the free

base.

HMTA. Abbreviation for hexamethylenetetra-

Derivation: From blood corpuscles, organic syn-

mine.

thesis.

Use: Medicine, feed additive, biochemical research,

HNM. Abbreviation for hexanitromannite.

dietary supplement.

See mannitol hexanitrate.

histidine monohydrochloride. mf:

•HCl•H

O. hnRNA. Heterogeneous nuclear RNA; refers col-

Properties: White needles, plates, or crystalline lectively to the variety of RNAs found in the nu-

654HO

cleus, including primary transcripts, partially pro-

Hofmann rule. When a quaternary ammonium

cessed RNAs and snRNA. The term hnRNA is often hydroxide containing different primary alkyl radi-

used just for the unprocessed primary transcripts, cals is decomposed, the least-substituted olefin is

however. formed preferentially.

Ho. Symbol for holmium.

Hofmann-Sand reaction. Olefin mercuration

with mercuric salts (halides, acetates, nitrates, or

sulfates) in aqueous solution. In alcoholic solutions,

hob. A hardened steel master die used to make

the accelerated reaction produces alkoxylalkyl com-

multiple mold cavities by forcing it into soft steel or

pounds.

beryllium-copper blanks.

Hofmann’s reaction. Reaction used for prepa-

Hoch-Campbell aziridine synthesis. For-

ration of a primary amine from an amide by treat-

mation of aziridines by treatment of ketoximes with

ment with a halogen (bromine usually) and caustic

Grignard reagents and subsequent hydrolysis of the

soda. The resulting amine has one fewer carbon

organometallic complex.

atom than the amide used.

Hodgkin, Dorothy C. (1910–1994). An

Egyptian-born chemist who was recipient of the

Hofmann’s Violet. (triethylrosaniline hydro-

Nobel Prize for chemistry in 1964. Her work in-

chloride; CI 42530). C

HCl. Water-soluble

volved determining the structure of vitamin B

, cho-

green powder.

lesterol iodide, and the antibiotic penicillin by using

Use: Dye for inks and textiles, biological stain.

X-ray crystallographic analysis. She was educated

at Oxford and Cambridge.

hog. A large enclosed chamber equipped either

with rotating knives or heavy hammers by which

Hoffman, Roald. (1937– ). A Polish-born

wood is disintegrated to a uniform degree of fi-

chemist who won the Nobel Prize for chemistry with

neness.

Fukui in 1981. His work involved applying the theo-

ries of quantum mechanics to predict the course of

hole. In semiconductor terminology, a hole is an

chemical reactions.

energy deficit in a crystalline lattice due to (1) elec-

trons ejected from unsatisfied covalent bonds at sites

Hofmann, August Whilhelm. (1818–1892).

where an atom is missing, i.e., a vacancy, or (2)

A German organic chemist who studied under Lie-

electrons supplied by atoms of impurities in the

big. While professor of chemistry at the Royal Col-

crystal, e.g., arsenic or boron. The free electrons

lege of Chemistry in London, he did original re-

from these sources move through the crystal, leav-

search on coal-tar derivatives that later led him into a

ing positively charged energy deficits that are con-

study of organic dyes. Perkin, who first synthesized

sidered to move as they become alternately filled

the dye mauveine in England, was a student of Hof-

and vacated by electrons, creating a flow of positive

mann. When the latter returned to Germany he con-

electricity.

tinued his work in the field of dyes, which became

See semiconductor.

the basis of German leadership in synthetic dye

manufacture that continued until World War I.

Holliday intermediate. An intermediate in ge-

netic recombination in which two double-stranded

Hofmann degradation. Formation of an ole-

DNA molecules are joined by virtue of a reciprocal

fin and a tertiary amine by pyrolysis of a quaternary

crossover involving one strand of each molecule.

ammonium hydroxide; useful for the preparation of

some cyclic olefins and for opening nitrogen-con-

holmium. Ho. Metallic element of atomic num-

taining ring compounds.

ber 67, group IIIB of the periodic table, one of the

rare-earth elements of the yttrium subgroup, aw

Hofmann isonitrile synthesis. Formation of

164.9303, valence of 3, no stable isotopes.

isonitriles by the reaction of primary amines with

See rare-earth metals.

chloroform in the presence of an alkali; the odor of

Properties: Crystalline solid with metallic luster. D

the isocyanide is a test for a primary amine.

8.803, mp 1470C, bp 2720C. Reacts slowly with

water; soluble in dilute acids. Has one of the highest

Hofmann-Loffler-Freytag reaction. For-

nuclear moments of any rare earth. Important mag-

mation of pyrrolidines or piperidines by thermal or

netic and electrical properties.

photochemical decomposition of protonated N-ha-

Occurrence: In gadolinite and monazite.

loamines.

Derivation: Reduction of the fluoride by calcium.

Grade: Lumps, ingots, bulk sponge, powder. High-

Hofmann-Martius rearrangement. Ther- est purity is nuclear grade 99.9+%.

mal conversion of N-alkylaniline hydrohalides to o- Use: Getter in vacuum tubes, research in electro-

and p-alkylanilines. chemistry, spectroscopy.

655 HOMOGENEOUS

holmium chloride. HoCl

. ber. It is reported to have suppressed growth of

Properties: Bright-yellow solid. Mp 718C, bp tumors in mice.

1500C. Soluble in water.

homoaromoline.

CAS: 17132-74-0. mf: C

holmium fluoride. HoF

Hazard: A poison.

Properties: Bright-yellow solid. Mp 1143C, bp

above 2200C. Insoluble in water.

homatropine. C

. An alkaloid.

Properties: White crystals. Mp 95.5C. Slightly solu-

holmium oxide. (holmia). Ho

ble in water.

Properties: Light-yellow solid. Slightly hygroscop-

Derivation: Condensation of tropine and mandelic

ic; soluble in inorganic acids.

acid.

Grade: 98–99%.

Hazard: Toxic by ingestion and inhalation.

Use: Refractories, special catalyst.

Use: Medicine (usually in the form of its salts).

holocellulose. The entire water-insoluble carbo-

homeobox. A short stretch of nucleotides whose

hydrate fraction of wood (60–80%). It is composed

base sequence is virtually identical in all the genes

of ␣-cellulose and hemicellulose; it contains hexo-

that contain it. It has been found in many organisms

san and pentosan polymers and varies widely in

from fruit flies to human beings. In the fruit fly, a

degree of crystallinity.

homeobox appears to determine when particular

groups of genes are expressed during development.

holoenzyme. A catalytically active enzyme in-

cluding all necessary subunits, prosthetic groups,

homeostasis. The maintenance of a dynamic

and cofactors.

steady state by regulatory mechanisms that compen-

sate for changes in circumstances. For example,

holography. Production of a unique three-di-

maintaining body temperature whether in a 20C or a

mensional image on photographic film by means of

4C environment.

an interference pattern created by a laser beam that is

split by a mirrorlike device. The beam is divided in

homeotic genes. Genes originally defined as

such a way that one portion is reflected from the

regulating the development of the pattern of seg-

subject while the other forms a direct image; the

ments in the Drosophila body plan. Similar genes

resulting superimposition results in an unusual 3-D

are now known to occur in most vertebrates.

effect.

Use: The technique has a number of practical applica-

homo-. A prefix meaning the same or similar;

tions in airplane flight control, missile guidance

usually designating a homolog of a compound, dif-

systems; other uses will undoubtedly develop.

fering in formula from the latter by an increase of

holopulping. A method for making paper pulp

See homologous series.

without use of sulfur compounds that has been pro-

posed as an eventual replacement for the kraft pro-

homocyclic. A ring compound containing only

cess (sodium sulfate). More selective delignification

one kind of atom in the ring structure, e.g., benzene.

of the wood fibers is obtained by alkaline oxidation

See heterocyclic.

of extremely thin (0.03 inch) wood chips at low

temperature and pressure, followed by solubiliza-

homogeneous. (Latin, “the same kind”). This

tion of the lignin fraction. Holopulping has other

term, in its strict sense, describes the chemical con-

advantages over the kraft process: (1) A 65–80%

stitution of a compound or element. A compound is

carbohydrate yield compared to 45–50% for kraft.

homogeneous since it is composed of one and only

(2) Holopulp may be used for a dense paper such as

one group of atoms represented by a formula. For

glassine or for a bulky board. Its use in tissue and

example, pure water is homogeneous because it con-

printing grades offers improved strength. (3) Low

tains no other substance than is indicated by its

temperatures and atmospheric pressure. (Kraft pulp-

formula, H

O. Homogeneity is a characteristic prop-

ing is carried out at 170C and under pressure.) Read-

erty of compounds and elements (collectively called

ily adaptable to continuous operation and automatic

substances) as opposed to mixtures. The term is

control. (4) Air pollution is greatly reduced because

often loosely used to describe a mixture or solution

the organic materials are burned and few odorous

composed of two or more compounds or elements

compounds are formed. Stream pollution is mini-

that are uniformly dispersed in each other. Actually,

mized by countercurrent washing. The remaining

no solution or mixture can be homogeneous; the

calcium sludge waste is easily disposed of without

situation is more accurately described by the phrase

harmful effects.

“uniformly dispersed.” Thus so-called homoge-

nized milk is not truly homogeneous; it is a mixture

holothurin. Steroid glucoside (saponin) having in which the fat particles have been mechanically

antibiotic properties, extracted from the sea cucum- reduced to a size that permits uniform dispersion and

656HOMOGENEOUS

consequent stability.

homomenthyl salicylate. (3,3,5-trimethylcy-

See mixture; compound; heterogeneous; substance. clohexyl salicylate). (CH

)

OOCC

OH. A

homolog of menthyl salicylate.

Properties: Light-yellow oil; odorless. Neutral and

homogeneous catalysis. See catalysis, ho-

nonirritating to the skin. Absorbs UV radiation in

mogeneous.

sunlight (2940–3200 A

). Insoluble in water; soluble

in alcohol, chloroform, and ether.

homogeneous reaction. A chemical reaction

Use: UV filter for antisunburn creams.

in which the reacting substances are in the same

phase of matter, i.e., solid, liquid, or gaseous.

homomorphs. Molecules similar in size and

See catalysis, homogeneous.

shape. They need have no other characteristics in

common. Many properties of several homomorphs

homogenization. A mechanical process for re-

can be predicted by knowing properties of one.

ducing the size of the fat particles of an emulsion

(usually milk) to uniform size, thus creating a colloi-

homophthalic acid. C

(CH

COOH)COOH.

dal system that is unaffected by gravity. The original

Properties: Light-tan powder.

diameter of the fat particles (6–10 microns) is re-

Use: Intermediate.

duced to 1–2 microns, with an increase in total sur-

face area of 4–6 times. This is done by passing the

homopolar adsorption. See apolar adsorp-

milk through a homogenizer (or colloid mill), a

tion.

machine having small channels, under a pressure of

2000–2500 psi at a speed of approximately 700 ft/

homopolymer. A natural or synthetic high poly-

sec. This operation not only brings about a perma-

mer derived from a single monomer. An example of

nently stable system, but also changes the properties

a natural homopolymer is rubber hydrocarbon,

of the milk in respect to taste, color, and the chemical

whose monomer is isoprene; a synthetic homopoly-

nature of the protective coating on the fat particles. It

mer is typified by polychloroprene or polystyrene,

also increases its sensitivity to light and its tendency

whose monomers are, respectively, chloroprene and

to foam. The forces involved are shear, impinge-

styrene.

ment, distention, and cavitation.

See polyblend.

See homogeneous; colloid mill.

homopolysaccharide. A polysaccharide made

homolog. A member of a chromosome pair in

up of only one type of monosaccharide unit.

diploid organisms, or a gene that has the same origin

and functions in two or more species.

homosalate. C

Properties: Liquid. Bp 162C (4 mm Hg), d 1.05, refr

homologies. Similarities in DNA or protein se-

index 1.51.

quences between individuals of the same species or

Use: Sunscreening agent.

among different species.

o-homosalicylic acid. See cresotic acid.

homologous chromosomes. A pair of chro-

mosomes containing the same linear gene se-

homotropic enzyme. An allosteric enzyme

quences, each derived from one parent.

that is modulated by its substrate.

homologous genetic recombination. Re-

homotropine.

combination between two DNA molecules of simi-

CAS: 87-00-3. mf: C

lar sequence, occurring in all cells; occurs during

Hazard: Moderately toxic by ingestion and subcuta-

meiosis and mitosis in eukaryotes.

neous routes.

homologous proteins. Proteins from different

homoveratric acid. (3,4-dimethoxyphenyla-

species having similar sequences and similar func-

cetic acid). (CH

COOH.

tions in each. For example, the many species that

Properties: Crystals. Mp 94–101C. Very slightly

have hemoglobin, which transports oxygen in all.

soluble in water; soluble in most organic solvents.

homologous recombination. Swapping of

homoveratrylamine. (3,4-dimethoxyphenyle-

DNA fragments between paired chromosomes.

thylamine). (CH

(CH

)

Properties: Colorless to pale-yellow liquid; slight

vanilla odor. D 1.09 (25/25C), solidifies 15C, bp

homologous series. A series of organic com-

295C (decomposes), refr index 1.5442–1.5452

pounds in which each successive member has one

(25C).

more CH

group in its molecule than the preceding

member. For instance CH

OH (methanol), C

(ethanol), C

OH (propanol), etc., form a homolo- homozygote. Having identical alleles at one or

gous series. more loci in homologous chromosome segments.

657 HOST STRAIN (BACTERIAL)

honey. A unique mixture of a number of low- Properties: From steam distillation of cones from

female Humulus lupulus L. or Humulus americanus

molecular-weight sugars (except sucrose) but in-

Nutt. (Fam. Moraceae). Yellow liquid; aromatic

cluding invert sugar. It is considerably sweeter than

odor. D: 0.825−0.926, refr index: 1.470−1.494 @

glucose.

20°. Sol in fixed oils, mineral oil; insol in glycerin,

Use: A food and sweetener since the beginning of

propylene glycol.

civilization, also has applications in medicine and

Use: Food additive.

tobacco processing.

“Honeywell Bulk Etch” [Honeywell]. TM

horizon. See soil.

for liquid, wafer-thinning materials.

Use: For rapid and uniform removal of all remnants

“Hormodin” [Merck]. TM for a formulation

of individual back grind damage.

of indolebutyric acid.

“Honeywell Polish Etch I & II”

17-hormoforin. See DHEA.

[Honeywell]. TM for a revealing liquid for

wafer-thinning materials.

hormone. An organic compound (peptide, ste-

Use: Used as a contour etch to delineate cracks and

roid) synthesized in small amounts by an endocrine

scratches.

tissue and carried in the blood to another tissue,

where it acts as a messenger to regulate the function

“Honeywell Texture Etch” [Honeywell].

of the target tissue.

TM for a liquid texture material.

Hormones regulate such physiological processes as

Use: On wafer-thinning materials to increases sur-

metabolism, growth, reproduction, molting, pig-

face area with uniform dimples to promote im-

mentation, and osmotic balance. They are some-

proved back metal tensile strength.

times called “chemical messengers.” Hormones

produced by one species usually show similar action

Hooker reaction. Oxidation of 2-hydroxy-3-

in other species. They vary widely in chemical na-

alkyl-1,4-quinones with dilute alkaline permanga-

ture, some are steroids–estrogen, progesterone, cor-

nate with shortening of the alkyl side chain by a

tisone–while others are amino acids (e.g., thyrox-

methylene group and simultaneous exchange of hy-

ine), polypeptides (vasopressin), low-molecular-

droxyl and alkyl or alkenyl group positions.

weight proteins (insulin), and conjugated proteins.

Amino acid and steroid hormones have been isolat-

Hooke’s law. When a load is applied to any

ed and many (including insulin) have been synthe-

elastic body so that the body is deformed or strained,

sized and are manufactured for medical purposes.

then the resulting stress (the tendency of the body to

Other types are made directly from the endocrine

resume its normal condition) is proportional to the

organs of animals.

strain. Stress is measured in units of force per unit

area, strain is the extent of the deformation. For

hormone, plant. See plant growth regulator.

example, when a bar of metal is subjected to a

stretching load, the extent of the increase in length of

the bar is directly proportional to the force per unit

hormone receptor. A protein in, or on, the

area, i.e., to the stretching load or stress. In general

surface of the target cells of a tissue that functions as

Hooke’s law applies only up to a certain stress called

a sensor for the hormone by binding the hormone

the yield strength.

and initiating a cellular response.

hopcalite. A mixture of oxides of copper, cobalt,

hormone therapy. Treatment that prevents

manganese, and silver.

certain cancer cells from getting the hormones they

Use: In gas masks, as a catalyst converting carbon

need to grow.

monoxide to carbon dioxide.

Hazard: Not safe for a respirator when nitroparaffin

“Hornstone” [Grace]. TM for zinc fluosilicate

vapors are present.

concrete hardener.

hop extract, modified.

host-guest chemistry. Study of molecules

Properties: An extract of hops by a variety of organic

which can enclose ions or atoms within their struc-

solvent extractions.

ture without the normal chemical bonding.

Use: Food additive.

See cavitands; buckminsterfullerene.

hops. A plant of the genus Humulus widely grown

in temperate climates.

host strain (bacterial). The bacterium used to

Use: Beer making.

harbor a plasmid. Typical host strains include

See brewing.

HB101 (general purpose E. coli strain), JM101 and

JM109 (suitable for growing M13 phages), XL1-

hops oil. Blue. Many host strains are available commercially.

658HOT

hot. Slang for highly radioactive, e.g., hot labora- “HTH-15” [Olin]. TM for an all-purpose ger-

tory. micide, disinfectant, and stain remover. Contains

15% of available chlorine and yields sodium hypo-

chlorite solutions directly when added to water.

hot-melt composition. See adhesive, hot-

Use: Dairy and poultry farm sanitation, for sterilizing

melt; sealant; asphalt; bitumen.

glasses and food utensils and general sanitation.

hot-short. See short.

“HTH Sock-It” [Arch]. TM for a shock sys-

tem for swimming pools.

Houben-Fischer synthesis. Formation of aro-

Use: To kill bacteria and control algae.

matic nitriles by basic hydrolysis of trichloromethyl

aryl ketimines obtained by Hoesch synthesis (but

HTST. Abbreviation for high-temperature short-

not from dichloro- or monochloromethyl aryl keti-

time, refers to processes such as pasteurization, ster-

mines). Acidic hydrolysis yields ketones.

ilization, etc.

Houben-Hoesch reaction. Synthesis of acyl-

HTU. Abbreviation for height of a transfer unit:

phenols from phenols or phenolic ethers by the ac-

the height of a distillation column or fractionating

tion of organic nitriles in the presence of hydrochlo-

tower in which unit separation is achieved by trans-

ric acid and aluminum chloride as catalyst.

fer from liquid to vapor or vice versa, of the materi-

als being separated. Unit separation is defined by the

Houdriflow process. A moving-bed type of

differential equation that takes into account the var-

catalytic cracking in which the catalyst pellets move

ying concentrations along the column. HTU is also

downward through a reactor concurrently with the

applied to extraction and other countercurrent sepa-

feed. The catalyst is then separated and regenerated

ration processes.

for further use.

See Thermofor process.

“Huberfill 93 and 96” [Huber]. TM for

sodium magnesium alumino silicate.

Houdry cracking process. Decomposition

Grade: Dry powder, slurry.

of petroleum or heavy petroleum fractions into more

Use: Print quality enhancements, paper fillers, car-

useful lower-boiling materials by heating at 500C

bonless copy intensifier, and titanium dioxide exten-

and 30 psi over a silica-alumina-manganese oxide

sion.

catalyst.

Huber, Robert. (1937– ). Awarded Nobel Prize

housekeeping genes. Those genes expressed in

for chemistry in 1988, along with Deisenhofer and

all cells because they provide functions needed for

Michel, for work that revealed the three-dimension-

sustenance of all cell types.

al structure of closely-linked proteins which are

essential to photosynthesis. Doctorate awarded in

“Howmet Castings” [Alcoa Kasei]. TM for

1963 by Technical University of Munich, Germany.

a wide variety of aluminum cast products.

Huber’s reagent. An aqueous solution of am-

HPA. Abbreviation for hydroxypropyl acrylate.

monium molybdate and potassium ferrocyanide

used for detecting free mineral acid. With the excep-

HPC black. Abbreviation for hard-processing

tion of boric acid and arsenic trioxide, free mineral

channel black.

acids produce a reddish-brown precipitate, or a tur-

See carbon black.

bidity with the reagent.

HPLC. Abbreviation of high-performance liquid

Hubl’s reagent. (1) 50 g iodine dissolved in 1 L

chromatography.

of 95% alcohol; (2) 60 g mercuric chloride dissolved

See: high-performance liquid chromatography.

in one L of alcohol; (3) Make up an iodine mono-

chloride solution from (1) and (2). Add an excess to

HPMPC. See (s)-1-(3-hydroxy-2-phosphonyl-

a known weight of the fat or oil dissolved in chloro-

methoxypropyl)cytosine.

form. The excess of iodine chloride can be estimated

by the potassium iodide and thiosulfate method. By

HS. (1) Symbol for hassium. (2) Abbreviation for

running a blank test, the amount of iodide absorbed

hydroxylamine sulfate.

can be estimated.

Use: Determination of iodine values of oils and fats.

“HTH” [Olin]. TM for a high-test calcium hy-

pochlorite product commercially available as a sta-

Hudson isorotation rules. For anomeric (␣

ble, water-soluble material in both granular and tab- and ␤) sugars, Hudson’s isorotation rule states that

let form, containing a minimum of 70% available (1) the rotation of carbon 1 in many sugar deriva-

chlorine as calcium hypochlorite. tives is affected in only a minor degree by changes in

Use: Bleaching, sterilizing, oxidizing. the structure of the rest of the molecule and (2)

659 HYALURONIC ACID

changes in the structure of carbon 1 affect in only a due to microorganisms in seawater. Detectable to

minor degree the rotation of the remainder of the 0.1 ppm in water.

molecule. Another way of stating the rule is to say Use: Drilling fluids, printing inks, plant growth.

that the rotation of any aldose derivative is the alge-

braic sum of A and B, where A is the contribution of

humidity, absolute. The pounds of water vapor

the anomeric center and B is the contribution of the

per pound of dry air in an air–water-vapor mixture.

rest of the molecule.

humidity indicator. A cobalt salt (e.g., cobal-

tous chloride) that changes color as the humidity of

Hudson lactone rule. The value of the rota-

the environment changes. Cobaltous compounds are

tion of aldonic acid lactones is decisively affected by

pink when hydrated and greenish-blue when anhy-

the configuration of that carbon atom whose hydrox-

drous.

yl group is engaged in the cyclization. If, in the

normal Fischer projection formula, the lactone ring

humidity, relative. The percentage relation be-

is written on the right, the lactone is dextrorotatory;

tween the actual amount of water vapor in a given

if it is written on the left, the lactone is levorotatory.

volume of air at a definite temperature and the maxi-

mum amount of water vapor that would be present if

human artificial chromosome (HAC). A

the air were saturated with water vapor at that tem-

vector used to hold large DNA fragments.

perature.

human gene therapy. Insertion of normal

“Humulin” [Lilly]. TM for synthetic insulin. It

DNA directly into cells to correct a genetic defect.

is the first recombinant DNA product to be made

commercially; approved by FDA.

human genome. The full collection of genes

needed to produce a human being.

humus. The organic component of soils contain-

ing humic acid, fulvic acid, and humin. It is formed

Human Genome Initiative. Collective name

by the decay of leaves, wood, and other vegetable

for several projects begun in 1986 to (1) create an

matter.

ordered set of DNA segments from known chromo-

Use: Top soil additive in horticulture, golf courses,

somal locations; (2) develop new computational

and truck gardens; available in 100-lb paper bags

methods for analyzing genetic map and DNA se-

and bulk shipments.

quence data; and (3) develop new techniques and

See soil (1).

instruments for detecting and analyzing DNA. This

DOE initiative is now known as the Human Genome

Hunsdiecker reaction. Synthesis of organic

Program. The national effort, led by DOE and NIH

halides by thermal decarboxylation of silver salts of

(now including the National Human Genome Re-

carboxylic acids in the presence of halogens.

search Institute), is known as the Human Genome

Project.

Hunter process. Production of titanium by re-

duction with sodium in an atmosphere of argon or

Human Genome Project. An international

helium.

research effort (led in the United States by the Na-

tional Institutes of Health and the Department of

“Huskey” [Specialty Lubes]. TM for special-

Energy) aimed at identifying and ordering every

ty lubricants with multiple applications.

base in the human genome.

HVP. See acid hydrolyzed proteins.

humectant. A substance having affinity for wa-

ter with stabilizing action on the water content of a

“Hyalure” [LifeCore].

material. A humectant keeps within a narrow range

CAS: 9067-32-7. TM for hyaluronic acid.

the moisture content caused by humidity fluctua-

Use: In orthopedic, ophthalmic, wound-care, drug-

tions. Example, glycerol.

delivery, and surgical applications.

Use: Tobacco, baked products, dentifrices.

hyaluronic acid. A polymer of acetylglycosa-

humic acid. A brown, polymeric constituent of mine, C

, and glucuronic acid occurring as

soils, lignite, and peat; it contains the brownish- alternate units with a high molecular weight. Found

black pigment melanin. It is soluble in bases, but in vitreous humor (of the eye), synovial fluid, patho-

insoluble in mineral acids and alcohols. It is not a logic joints, group A and C hemolytic streptococci,

well-defined compound, but a mixture of polymers and skin. It appears to bind water in the interstitial

containing aromatic and heterocyclic structures, spaces, forming a gel-like substance which holds the

carboxyl groups, and nitrogen. An excellent chelat- cells together. Its solutions are highly viscous. The

ing agent, important in the exchange of cations in polymeric structure is broken down by the enzyme

soils. It is a natural stream pollutant and is thought to hyaluronidase.

be capable of triggering the “red tide” phenomenon See “Actimoist” [Active].

660“HYAMINE”

“Hyamine” [Rohm & Haas]. TM for qua- “Hydraid” [Nalco]. TM for a family of water-

ternary-ammonium-type bactericides, algicides, soluble organic polymers, some cationic, anionic,

and fungicides, supplied as water-soluble crystals or and nonionic of various molecular weights and coa-

gulation properties.

aqueous solutions.

Use: Paper and pulp mill retention, drainage and

clarification aids.

Hyatt, John Wesley. (1837–1920). Hyatt is

generally credited as being the father of the plastics

hydralazine hydrochloride. (1-hydrazino-

industry. In 1869, he and his brother patented a

phthalazine hydrochloride). C

NHNH

HCl.

mixture of cellulose nitrate and camphor which

Properties: White, crystalline powder; odorless. Mp

could be molded and hardened. Its first commercial

270–280C (decomposes). Very slightly soluble in

use was for billiard balls. The TM “Celluloid” was

ether and alcohol; soluble in water, pH (2% solu-

the first ever applied to a synthetic plastic product;

tion) 3.5–4.5.

its flammability hazard limits its use.

Grade: NF.

Use: Medicine (antihypertensive agent)

hybrid. The offspring of genetically different

parents.

“Hydral”700 Series. [ALCOA] Al

•3H

See heterozygote.

or Al(OH)

, of extremely fine, uniform particle size.

TM for several grades of hydrated aluminum oxides.

hybridization. The reaction by which the pair-

Properties: Fluffy, snow-white powders.

ing of complementary strands of nucleic acid oc-

Use: As fillers in rubber, paper, plastics, adhesives,

curs. DNA is usually double-stranded, and when the

polishes, inks, paints, cosmetics, and as a flame

strands are separated they will re-hybridize under

retarder in plastics.

the appropriate conditions. Hybrids can form be-

tween DNA-DNA, DNA-RNA or RNA-RNA. They

“Hydraphthal” [Du Pont]. TM for a combi-

can form between a short strand and a long strand

nation solvent and detergent for textile scouring.

containing a region complementary to the short one.

Imperfect hybrids can also form, but the more im-

hydrargaphen. (phenylmercury

perfect they are, the less stable they will be (and the

methylenedinaphthalenesulfonate).

less likely to form). To “anneal” two strands is the

CAS: 14235-86-0. C

same as to “hybridize” them.

Properties: Extremely fine powder. Insoluble in wa-

ter. Forms colloidal dispersons with strong adsorp-

“Hydan” [Du Pont]. TM for methionine hy-

tive power in sodium or potassium dinaphthylmeth-

droxy analog c. 90%.

ane disulfonates.

Use: A source of methionine (an essential amino

Hazard: A poison.

acid) for poultry, dog, and livestock feeds.

Use: Biocide for protection of wool, leather, paints,

and wood products.

hydantoin. (glycolylurea).

CAS: 461-72-3. NHCONHCOCH

hydrase. See hydrolase.

Properties: White, odorless solid; crystallizing in

needles. Mp 220C. Slightly soluble in water and

hydrate. See hydration.

ether; soluble in alcohols and solutions of alkali

hydroxides.

hydrated aluminum oxide. See alumina

Use: Intermediate in the synthesis of pharmaceuti-

trihydrate.

cals, textile lubricants, and certain high polymers,

including epoxy resins.

hydrated silica. See silicic acid.

hydnocarpic acid. C

. A component of

hydration. (1) The reaction of molecules of wa-

chaulmoogra oil.

ter with a substance in which the H−OH bond is not

split. The products of hydration are called hydrates,

hydrabamine pencillin V. (hydrabamine

e.g.,

phenoxymethylpenicillin).

CuSO

+5H

O → CuSO

•5H

O A given compound

Properties: A water-insoluble mixture of crystalline

often forms more than one hydrate; the hydration of

phenoxymethylpenicillin salts consisting chiefly of

sodium sulfate can give Na

•10H

O (decahyd-

the salt of N,N

′

-bis(dehydroabietyl)ethyl-

rate), Na

•7H

O (heptahydrate), and

enediamine with smaller amounts of the salts of the

•H

O (monohydrate). In formulas of hy-

dihydro and tetrahydro derivatives.

drates, the addition of the water molecules is con-

Use: Medicine (antibacterial).

ventionally indicated by a centered dot. The water is

usually split off by heat, yielding the anhydrous

hydracrylic acid, acrylate. compound.

CAS: 24615-84-7. mf: C

. See water of crystallization; gas hydrate. (2) The

Hazard: A severe skin irritant. strong affinity of water molecules for particles of

661 HYDRAZINE

dissolved or suspended substances that is the funda- bore, and is evacuated to a pipeline. The sand and

mental cause of electrolytic dissociation. Ions and bauxite are called “proppants” by petroleum engi-

neers as they prevent the fissures from closing. Sand

other charged particles thus acquire a tightly held

is used in shallower wells and bauxite in formations

film of water, an effect that is important in the

over 10,000 ft deep.

stabilization of colloidal solutions. The phenome-

See chemical flooding.

non is also called solvation. The term “hydration” is

used in the paper industry to describe the combina-

tion of water with wood pulp in the beater, as a result

hydraulic lime. See lime, hydraulic.

of which fiber-to-fiber adhesion is increased by hy-

drogen bonding.

hydraulic press. A simple machine (the only

See solvation.

one discovered since prehistoric times) that operates

on Pascal’s principle (1650): pressure applied to a

hydratropic aldehyde dimethyl acetal.

unit area of a confined liquid is transmitted equally

See 2-phenylpropionaldehyde dimethyl acetal.

in all directions throughout the liquid. A hydraulic

press is comprised of a large piston in an enclosed

hydraulic. (1) Descriptive of a machine or opera-

chamber; its top is attached to a platen that rests on

tion in which a liquid is used to exert or transfer

the members of a metal frame when the press is

pressure, e.g., hydraulic press, hydraulic fracturing.

open. Water (or oil) is pumped into the chamber

The liquid is usually water, but it may also be of

through a valve; once it has been filled, whatever

higher viscosity such as a heavy oil or glycol-type

pressure per square inch is applied at the valve will

lubricant, as in brake fluid. (2) Descriptive of a

be transmitted to every square inch of the piston and

material that hardens on addition of water, e.g.,

of the walls of the chamber as well. Thus, for a piston

hydraulic cement.

whose cross-sectional area is 100 sq in., 10 psi at the

valve will exert 1000 lb pressure on the bottom of the

hydraulic barking. Removal of bark from logs

piston, causing it to rise and the press to close. The

by impingement of a stream of water delivered from

pressure on the object being pressed varies inversely

one or more nozzles at a pressure of 1200–1400 psi.

with its area. Hydraulic presses exerting pressures

Several types of machines are used, the best known

up to 15 tons are used for shaping steel products.

being the Hansel barker.

Less dramatic are those for molding rubber and

plastics, compressing laminates, de-watering solids,

hydraulic cement. See cement, hydraulic.

and expressing vegetable oils. Some have up to a

dozen platens (decks) for multiple-product work.

hydraulic fluid. A liquid or mixture of liquids

The same principle is used to activate plungers on

designed to transfer pressure from one point to an-

injection-molding presses.

other in a system on the basis of Pascal’s law, i.e.,

pressure on a confined liquid is transmitted equally

in all directions. For industrial use, such fluids are

hydrazine. (hydrazine base; hydrazine, anhy-

based on paraffinic and cycloparaffinic petroleum

drous; diamine).

fractions, usually with added antioxidant and vis-

CAS: 302-01-2. H

NNH

cosity index improvers. Flame-resistant types in-

Properties: Colorless, fuming, hygroscopic liquid.

clude additives such as phosphate esters or emul-

Mp 2.0C, bp 113.5C, d 1.004 (25/4C), bulk density

sions of water and ethylene glycol. The brake fluids

8.38 lb/gal, flash p 126F (52.2C) (OC), autoign temp

used in autos are composed of (1) a lubricant (poly-

518F (270C). Miscible with water and alcohol; in-

propylene glycol of 1000–2000 mw, a castor oil

soluble in chloroform and ether. Strong reducing

derivative, or a synthetic polymeric mixture of mo-

agent and diacidic but weak base. Combustion of

nobutyl ethers of oxyethylene and oxypropylene

hydrazine is highly exothermic, yielding 148.6 kcal/

glycols); (2) a solvent blend (mixture of glycol

mole; nitrogen and water are products.

ethers); and (3) additives for corrosive resistance,

Derivation: The preferred method is a two-step pro-

buffering, etc.; bp 375–550F. The composition and

cess: (1) reaction of sodium hypochlorite and am-

performance characteristics are specified by the So-

monia to yield chloramine (NH

Cl) and sodium hy-

ciety of Automotive Engineers.

droxide; (2) reaction of chloramine, ammonia, and

sodium hydroxide to yield hydrazine, sodium chlo-

hydraulic fracturing. A method of enhanced ride, and water. Noteworthy is the need to carry out

recovery of natural gas and petroleum. An aqueous the reactions in the presence of such colloidal mate-

solution of a water-soluble gum (e.g., guar), in rials as gelatin, glue, or starch to prevent unwanted

which coarse sand or sintered bauxite is suspended, side reactions that would reduce the yield of hydra-

is introduced through a well bore under extremely zine. An older method utilized the reaction of sodi-

high pressure into the rock structure in which the gas um hypochlorite or calcium hypochlorite with urea.

or oil is entrained. This creates minute fissures (frac- Grade: To 99% pure.

tures) in the rock which are held open by the sus- Hazard: Severe explosion hazard when exposed to

pended particles after the liquid has drained off. The heat or by reaction with oxidizers. Toxic by inges-

hydrocarbon flows through these fissures to the well tion, inhalation, and skin absorption; strong irritant

662HYDRAZINE

to skin and eyes; a carcinogen (OSHA). TLV: 0.1 Hazard: Severe explosion risk.

ppm. Use: Rocket propellant.

Use: Reducing agent for many transition metals and

some nonmetals (arsenic, selenium, tellurium), as

hydrazine sulfate. (diamine sulfate; diamido-

well as uranium and plutonium; corrosion inhibitor

gen sulfate).

in boiler feedwater and reactor cooling water; waste-

CAS: 10034-93-2. NH

•H

water treatment; electrolytic plating of metals on

Properties: White, crystalline powder. D 1.37, mp

glass and plastics; nuclear fuel reprocessing; redox

85C. Very soluble in hot water, soluble at 1 part in 33

reactions; polymerization catalyst; shortstopping

cold water, insoluble in alcohol, stable in storage,

agent; fuel cells; blowing agent; scavenger for

strong reducing agent.

gases; drugs and agricultural chemicals (maleic hy-

Hazard: A carcinogen (OSHA).

drazide); component of high-energy fuels; rocket

Use: Manufacture of chemicals, condensation reac-

propellant.

tions, catalyst in making acetate fibers. Analysis of

minerals, slags, and fluxes; determination of arsenic

hydrazine acid tartrate. (hydrazine tar- in metals; separation of polonium from tellurium;

trate). N

•C

. fungicide, germicide.

Properties: Colorless crystals. Mp 182–183C. Solu-

ble in water.

hydrazine tartrate. C

Hazard: See hydrazine.

Properties: Colorless crystals. Mp 182C.

Use: Deposition of metals, as in silvering mirrors.

hydrazine, compd. with borane (1:1).

CAS: 14931-40-9. mf: BH

2-hydrazino-n,n-dimethylethanamine.

Hazard: A poison by ingestion and inhalation. May

CAS: 1754-57-0. mf: C

be unstable at room temperature.

Hazard: A poison. Moderately toxic by ingestion

and inhalation.

hydrazine dihydrochloride. N

•2HCl.

Properties: Colorless crystals. D 1.42, mp 198C

hydrazobenzene. (1,2-diphenylhydrazine).

(loses hydrogen chloride), bp 200C (decomposes).

CAS: 122-66-7. C

NHNHC

Soluble in water; slightly soluble in alcohol.

Properties: Mw 184.24, mp 123–126C, d 1.158(16/

4C).

hydrazine hydrate. (diamide hydrate).

CAS: 7803-57-8. H

NNH

•H

hydrazoic acid. (hydrogen azide).

Properties: Colorless fuming liquid. Fp −51.7C, bp

CAS: 7782-79-8. HN

119.4C, d 1.032, bulk d 8.61 lb/gal, flash p (OC)

Properties: Colorless, volatile liquid; obnoxious

163F. Miscible with water and alcohol; insoluble in

odor. Fp −80C, bp 37C. Soluble in water.

chloroform and ether. Strong reducing agent; weak

Derivation: Reaction of hydrazine and nitrous acid,

base. Combustible.

or of nitrous oxide and sodium amide (with heat).

Hazard: See hydrazine.

Hazard: Dangerous explosion risk when shocked or

Use: Chemical intermediate, catalyst, solvent for in-

heated. Strong irritant to eyes and mucous mem-

organic materials.

branes. TLV: CL 0.1 ppm (vapor)

hydrazine monobromide. N

•HBr.

“Hydrex” [Huber]. (sodium magnesium alu-

Properties: White, crystalline flakes. Mp 81–87C,

minosilicate) TM for titanium dioxide extenders.

decomposes at approximately 190C. Soluble in wa-

Use: Print enhancement; imparting high brightness

ter and lower alcohols; insoluble in most organic

and opacity; as a paper filer; and carbonless copy

solvents.

intensifier.

Grade: 95%.

Use: Soldering flux.

hydride. An inorganic compound of hydrogen

with another element. Some are ionic and others are

hydrazine monochloride. N

•HCl.

covalent. Hydrides may be either binary or complex;

Properties: White, crystalline flakes. Mp 87–92C,

the latter are transition-metal complexes, e.g., car-

decomposes at approximately 240C. Soluble in wa-

bonyl hydrides and cyclopentadienyl hydrides.

ter (37g/100g H

O at 20C); somewhat soluble in

Most common are hydrides of sodium, lithium, alu-

lower alcohols; insoluble in most organic solvents.

minum, boron, etc.

Hazard: Flammable, dangerous fire risk, react vio-

hydrazine nitrate. N

. lently with water and oxidizing agents. Irritant.

Hazard: Severe explosion risk. Poison. See lithium aluminum hydride; sodium borohydride.

hydrazine perchlorate. N

•HClO

•

O. hydriodic acid.

Properties: Solid. D 1.939, mp 137C, bp 145C. De- CAS: 10034-85-2.

composes in water; soluble in alcohol; insoluble in Properties: Colorless or pale-yellow liquid (an aque-

ether, benzene, chloroform, and carbon disulfide. ous solution of hydrogen iodide, which is a gas at

663 HYDROCARBON

room temperature), a constant-boiling solution is

I. Aliphatic (straight-chain)

formed (bp 127, d 1.7) containing 57% hydrogen

(1) Paraffins (alkanes): generic formula C

2n+2

iodide; strong acid and an active reducing agent.

Saturated, single bonds only.

Derivation: (1) By passing hydrogen with iodine

(2) Olefins: generic formula C

vapor over warm platinum sponge and absorption in

(a) alkenes: unsaturated (one double bond).

water. (2) By the action of iodine on a solution of

(b) alkadienes: unsaturated (two double

hydrogen sulfide.

bonds) (butadiene).

Grade: Technical, 47%; NF, diluted, 10%.

(3) Acetylenes: generic formula C

2n-

. Unsatu-

Hazard: Strong irritant to eyes and skin.

rated (triple bond).

Use: Preparation of iodine salts, organic prepara-

(4) Acyclic terpenes. Unsaturated (polymers of

tions, analytical reagent, disinfectant, pharmaceuti-

isoprene, C

cals.

Note: Some aliphatic compounds have branched

See hydrogen iodide.

chains in which the subchain also contains carbon

atoms (isobutane); both chains are essentially

straight.

hydroabietyl alcohol. See dihydroabietyl al-

II. Cyclic (closed ring)

cohol.

(1) Alicyclic: three or more carbon atoms in a

ring structure with properties similar to

those of aliphatics.

hydrobiotite. A natural ore of magnesium, iron,

(a) Cycloparaffins (naphthenes): saturated

and aluminum silicate occurring in Montana. Source

compounds often having a boat or chair

of verxite.

structure, e.g., cyclohexane, cyclopen-

tane.

(b) Cycloolefins: unsaturated, two or more

hydroboration. The reaction of diboranes either

double bonds, e.g., cyclopentadiene (2),

with alkenes (olefins) to form trialkylboron com-

cyclooctatetraene (4).

pounds or with acetylene to yield alkenylboranes.

Much research has been devoted to developing these

(triple bond).

reactions, the products of which are called organo-

(2) Aromatic: unsaturated, hexagonal ring

boranes. They are useful in many complex organic

structure (three double bonds), single rings

syntheses, including prostaglandins and insect pher-

and double or triple fused rings.

omones.

(a) benzene group (1 ring).

See borane; organoborane; carborane.

(b) naphthalene group (2 rings).

(3) Cyclic terpenes: monocyclic (dipentene); di-

hydrobromic acid.

cyclic (pinene).

CAS: 10035-10-6. Hydrogen bromide in aqueous

Note: Olefinic (isoprenoid) hydrocarbons are pro-

solution.

duced by a number of plants, notably Hevea brazi-

Properties: Colorless or faintly yellow liquid con-

liensis (rubber), guayule, and various members of

sisting of an aqueous solution of hydrogen bromide,

the Euphorbiaceae family. Current research on the

which is a gas at room temperature. Soluble in water

latter group indicates that they could be used as a

and alcohol, a constant-boiling solution is formed of

source of liquid fuels and chemical feedstocks by

d 1.49, containing 48% hydrogen bromide; bp at 700

genetic modification of the plants and control of

mm Hg (122C), saturated solution contains 68.8%

their molecular constitution. It is estimated that oil

hydrogen bromide at 0C. Hydrobromic acid is a

obtained by large-scale cultivation of such plants,

strong acid and sensitive to light. Noncombustible.

which grow well in semi-arid environments, could

Derivation: By dissolving hydrogen bromide in wa-

become economically competitive with petroleum

ter or by distilling from a mixture of sodium bromide

within a few years.

and 50% sulfuric acid.

See guayule; biomass; copaiba.

Grade: Technical 40%; medicinal 48%, 62%.

Hazard: Strong irritant to eyes and skin.

hydrocarbon gas streams. A hydrocarbon

Use: Analytical chemistry, solvent for ore minerals,

such as methane is contacted with a catalyst under

manufacture of inorganic and some alkyl bromides,

moderate conditions of temperature and pressure

alkylation catalyst.

and decomposed into carbon, which remains on the

See hydrogen bromide.

catalyst, and hydrogen, which is mechanically re-

moved. The hydrogen produced is about 94% pure

when the charge stock is methane.

hydrocarbon. An organic compound consisting

exclusively of the elements carbon and hydrogen.

Derived principally from petroleum, coal tar, and

hydrocarbon, halogenated. A hydrocarbon

plant sources. Following is a resume of the principal in which one or more of the hydrogen atoms has

types. been replaced by fluorine, chlorine, bromine, or

664HYDROCELLULOSE

iodine. Examples: carbon tetrachloride, chloroben- ter, thus increasing viscosity and imparting

zene, chloroform, trifluoromethane. This greatly in- smoothness and body texture to the product, even in

concentrations of less than 1%. Natural types are

creases the anesthetic and narcotic action of aliphat-

plant exudates (gum arabic), seaweed extracts

ic hydrocarbons. Many halogenated hydrocarbons

(agar), plant seed gums or mucilages (guar gum),

are highly toxic; some may detonate on contact with

cereal gums (starches), fermentation gums (dex-

barium. A number of the chlorinated types are used

tran), and animal products (gelatin). Semisynthetic

as insecticides.

types are modified celluloses and modified starches.

See fluorocarbon; chlorofluorocarbon.

Completely synthetic types are also available, e.g.,

polyvinylpyrolidone. Most are carbohydrate poly-

hydrocellulose. See cellulose, hydrated.

mers but a few such as gelatin and casein are pro-

teins.

hydrochlorbenzethylamine.

CAS: 17692-34-1. mf: C

ClN

Hazard: Moderately toxic by ingestion.

hydrocortisone. (17-hydroxycorticosterone;

cortisol; hydrocortisone alcohol).

hydrochloric acid. (HCl).

CAS: 50-23-7. C

. An adrenal cortical steroid

CAS: 7647-01-0. Hydrogen chloride in aqueous so-

hormone.

lution.

Properties: White, crystalline powder;, odorless;

Properties: Colorless or slightly yellow, fuming,

bitter taste. Sensitive to light. Mp 212–220C with

pungent liquid. Flash p none. A constant-boiling

some decomposition. Soluble in sulfuric acid; par-

acid containing 20% hydrochloric acid is formed.

tially soluble in alcohol and propylene glycol.

Hydrochloric acid is a strong, highly corrosive acid.

Derivation: Isolation from extracts of adrenal

The commercial “concentrated” or fuming acid con-

glands, synthesis from other steroids.

tains 38% hydrochloric acid and has a d 1.19. Solu-

Grade: USP.

ble in water, alcohol, and benzene. Noncombustible.

Use: Medicine (antiinflammatory agent), also used as

Derivation: Dissolving hydrogen chloride in water

the acetate and sodium succinate salts.

at various concentrations.

See cortisone.

Grade: USP (35–38%), NF dilution (10%), technical

(usually 18, 20, 22, 23 degrees Be´, corresponding to

hydrocracking. The cracking of petroleum or its

28, 31, 35, 37% hydrogen chloride), FCC.

products in the presence of hydrogen. Special cata-

Hazard: Toxic by ingestion and inhalation, strong

lysts are used, for example, platinum on a solid base

irritant to eyes and skin. TLV: CL 5 ppm

of mixed silica and alumina or zinc chloride.

Use: Acidizing (activation) of petroleum wells, boil-

See hydrogenation; hydrogenolysis; hydroforming.

er scale removal, chemical intermediate, ore reduc-

tion, food processing (corn syrup, sodium gluta-

mate), pickling and metal cleaning, industrial

hydrocyanic acid. (prussic acid; hydrogen

acidizing, general cleaning, e.g., of membrane in

cyanide; formonitrile).

desalination plants, alcohol denaturant, laboratory

CAS: 74-90-8. HCN.

reagent.

Properties: Water-white liquid at temperatures be-

See hydrogen chloride.

low 26.5C; faint odor of bitter almonds. Usual com-

mercial material is 96–99% pure. D (Liquid) 0.688

hydrocinnamic acid. (3-phenylpropionic

(20/4C), (gas) 0.938 g/L, bp 26.5C, fp −13.3C, flash

acid). C

COOH.

p0F(−17.7C). Soluble in water. The solution is

Properties: Crystals with hyacinth-rose odor. Mp

weakly acidic, sensitive to light. When not absolute-

46C, bp 280C. Soluble in hot water, alcohol, ben-

ly pure or stabilized, hydrogen cyanide polymerizes

zene, ether.

spontaneously with explosive violence. Miscible

Derivation: Reduction of cinnamic acid with sodium

with water, alcohol, soluble in ether, autoign temp

amalgam.

1000F (537C).

Use: Fixative for perfumes, flavoring.

Derivation: (1) By catalytically reacting ammonia

and air with methane or natural gas. (2) By recovery

hydrocinnamic alcohol. See phenylpropyl

from coke oven gases. (3) From bituminous coal and

alcohol.

ammonia at 1250C. Hydrogen cyanide occurs natu-

rally in some plants (almond, oleander).

hydrocinnamic aldehyde. See phenylpropyl

Grade: Technical (96–98%), 2, 5, and 10% solu-

aldehyde.

tions. All grades usually contain a stabilizer, usually

0.05% phosphoric acid.

hydrocinnamyl acetate. See phenylpropyl

Hazard: Flammable, dangerous fire risk, explosive

acetate.

limits in air 6–41%. Toxic by ingestion inhalation,

and skin absorption. TLV: ceiling 4.7 ppm.

hydrocolloid. A hydrophilic colloidal material Use: Manufacture of acrylonitrile, acrylates, adiponi-

used largely in food products as emulsifying, thick- trile, cyanide salts, dyes, chelates, rodenticides, pes-

ening, and gelling agents. They readily absorb wa- ticides.

665 HYDROGEN

“Hydro-Darco” [Norit]. TM for activated car- hydrofluosilicic acid. See fluosilicic acid.

bon based adsorbent.

Use: For purification of water, fine chemicals, waste-

“Hydrofol” [Ashland]. (stearic acid).

water, air, and pharmaceuticals. Used for recovery

CAS: 57-11-4. TM for an additive.

of valuable products as in gold and organic solvents.

Use: In esters, greases, candles, crayons, cosmetics,

metallic salts, mono- and diglyceride, shaving

creams, textile auxiliaries, white stearates, waxes,

hydrodealkylation. (HDA). A type of hydroge-

and rubber compounding.

nation used in petroleum refining in which heat and

pressure in the presence of hydrogen are used to

remove methyl or larger alkyl groups from hydro-

hydroforming. The use of hydrogen in the pres-

carbon molecules, or to change the position of such

ence of heat, pressure, and catalysts (usually plati-

groups. The process is used to upgrade products of

num) to convert olefinic hydrocarbons to branched

low value, such as heavy reformate fractions, naph-

chain paraffins (isomerization) to yield high-octane

thenic crudes, or recycle stocks from catalytic crack-

gasoline. Catforming and similar terms are often

ing. Also toluene and pyrolysis gasoline are convert-

used in the same sense.

ed to benzene and methyl naphthalenes to

naphthalene by this process.

hydrofuramide. (furfuramide).

See transalkylation.

CAS: 494-47-3. OC

CH(NCHC

Properties: Light-brown to white powder. Mp 117C,

hydrodistillation. (steam distillation). Re-

boils about 250C with decomposition. Insoluble in

moval of essential oils from plant components

cold water; soluble in alcohol and ether.

(flowers, leaves, bark, etc.) by the use of high-tem-

Derivation: Treatment of furfural with ammonia.

perature steam. The process is used chiefly in the

Use: Rubber accelerator, hardening agent for resins,

perfume and fragrance industry.

rodenticides, fungicides.

hydrofining. A petroleum refining process in

hydrogasification. Production of gaseous or

which a limited amount of hydrogenation converts

liquid fuels by direct addition of hydrogen to coal.

the sulfur and nitrogen in a petroleum fraction to

See gasification.

forms in which they can be easily removed. Hydro-

fining is generally a separate treatment prior to more

hydrogen.

extensive hydrogenation. The usual catalysts are

CAS: 1333-74-0. H

. Nonmetallic element of atomic

oxides of cobalt and molybdenum. Desulfurization,

number 1, group IA of periodic table, atomic weight

ultrafining, and catfining have a similar meaning.

1.0079, valence of 1. Molecular formula is H

. Iso-

topes: deuterium (

D), tritium (

T). Hydrogen dis-

hydroflumethiazide. (trifluoromethylhydroth-

covered by Cavendish in 1766, named by Lavoisier

iazide). C

in 1783.

Properties: White, crystalline solid; odorless. Mp

Properties: A diatomic gas. D 0.08999 g/L, d 0.0694

260–275C. Insoluble in water and acid; soluble in

(air

1.0), specific volume 193 cu ft/lb (21.1C), fp

dilute alkali but unstable in alkaline solutions.

−259C, bp −252C, autoign temp 1075F (580C).

Grade: NF.

Very slightly soluble in water, alcohol, and ether;

Use: Medicine (antihypertensive).

Noncorrosive; can exist in crystalline state at from

4–1 K; classed as an asphyxiant gas; rate of perme-

hydrofluoric acid.

ation through solids is approximately four times that

CAS: 7664-39-3. Hydrogen fluoride in aqueous so-

of air.

lution.

Occurrence: Chiefly in combined form (water, hy-

Properties: Colorless, fuming, mobile liquid. Bp

drocarbons, and other organic compounds), traces in

(38% solution) 112C. Will attack glass and any

earth’s atmosphere. Unlimited quantities in sun and

silicon-containing material.

stars. It is the most abundant element in the universe.

Derivation: Dissolving hydrogen fluoride in water to

Derivation: (1) Reaction of steam with natural gas

various concentrations.

(steam reforming) and subsequent purification; (2)

Grade: CP, technical, 38%, 47%, 53%, 70%.

partial oxidation of hydrocarbons to carbon monox-

Hazard: Toxic by ingestion and inhalation, highly

ide and interaction of carbon monoxide and steam;

corrosive to skin and mucous membranes. TLV:

(3) gasification of coal (see Note 1); (4) dissociation

ceiling 3 ppm.

of ammonia; (5) thermal or catalytic decomposition

Use: Aluminum production, fluorocarbons, pickling

of hydrocarbon gases; (6) catalytic reforming of

stainless steel, etching glass, acidizing oil wells,

naphtha; (7) reaction of iron and steam; (8) catalytic

fluorides, gasoline production (alkylation), process-

reaction of methanol and steam; (9) electrolysis of

ing uranium.

water (see Note 2). In view of the importance of

See hydrogen fluoride.

hydrogen as a major energy source of the future,

development of the most promising of these meth-

hydrofluorosilicic acid. Legal label name ods may be expected.

(Rail) for fluosilicic acid. See gasification.

666ORTHO-HYDROGEN

Note 1: The projected cost of producing hydrogen

hydrogenated sperm oil.

Use: Food additive.

from coal by proven gasification techniques has

been estimated to be competitive with gasoline.

Note 2: More efficient methods than electrolysis for

hydrogenated terphenyls.

obtaining hydrogen from water are under investiga-

CAS: 61788-32-7. Complex mixtures of ortho-

tion. One of these is thermochemical decomposi-

meta-, and para-terphenyls in various stages of hy-

tion. Another is photochemical decomposition by

drogenation.

solar radiation, either directly or via a solar power

Hazard: TLV: 0.5 ppm.

generator. Photolytic decomposition of water with

Use: A heat-transfer medium and plasticizer.

platinum catalyst has been achieved. Hydrogen can

also be obtained by photolytic decomposition of

hydrogenated vegetable oil. See “Neobee”

hydrogen sulfide with cadmium sulfide catalyst.

[Stepan].

See photolysis; thermochemistry.

Method of purification: By scrubbing with various

hydrogenation. Any reaction of hydrogen with

solutions (see especially the Girbitol absorption pro-

an organic compound. It may occur either as direct

cess). For very pure hydrogen, by diffusion through

addition of hydrogen to the double bonds of unsatu-

palladium.

rated molecules, resulting in a saturated product, or

Grade: Technical, pure, from an electrolytic grade of

it may cause rupture of the bonds of organic com-

99.8% to ultra-pure with less than 10 ppm impuri-

pounds, with subsequent reaction of hydrogen with

ties.

the molecular fragments. Examples of the first type

See para-hydrogen.

(called addition hydrogenation) are the conversion

Hazard: Highly flammable and explosive, danger-

of aromatics to cycloparaffins and the hydrogena-

ous when exposed to heat or flame, explosive limits

tion of unsaturated vegetable oils to solid fats by

in air 4–75% by volume.

addition of hydrogen to their double bonds. Exam-

Use: Production of ammonia, ethanol, and aniline;

ples of the second type (called hydrogenolysis) are

hydrocracking, hydroforming, and hydrofining of

hydrocracking of petroleum and hydrogenolysis of

petroleum; hydrogenation of vegetable oils; hydro-

coal to hydrocarbon fuels.

genolysis of coal; reducing agent for organic synthe-

See hydrogenolysis; hydrocracking; hydroforming.

sis and metallic ores; reducing atmosphere to pre-

vent oxidation; as oxyhydrogen flame for high

temperatures; atomic-hydrogen welding; instru-

hydrogen azide. See hydrazoic acid.

ment-carrying balloons; making hydrogen chloride

and hydrogen bromide; production of high-purity

hydrogen bond. An attractive force, or bridge,

metals; fuel for nuclear rocket engines for hyperson-

occurring in polar compounds such as water in

ic transport; missile fuel; cryogenic research. A trea-

which a hydrogen atom of one molecule is attracted

tise on the physical properties of hydrogen compiled

to two unshared electrons of another. The hydrogen

by the National Bureau of Standards is available

atom is the positive end of one polar molecule and

from the U.S. Government Printing Office.

forms a linkage with the electronegative end of an-

Note: A safe storage method for hydrogen for possi-

other such molecule. In the formula below, the hy-

ble use as automotive fuel involves the use of metal

drogen atom in the center is the “bridge.”

hydrides from which the hydrogen is released at

specified temperatures. Iron titanium hydride has

been found the most satisfactory.

ortho-hydrogen. See para-hydrogen.

Hydrogen bonds are only one-tenth to one-thir-

teenth as strong as covalent bonds but they have

para-hydrogen. Type of molecular hydrogen

pronounced effects on the properties of substances

preferred for rocket fuels. Molecular hydrogen (H

)

in which they occur, especially as regards melting

exists in two varieties, ortho- and para-, named ac-

point, boiling point, and crystalline structure. They

cording to their nuclear spin types. Ortho-hydrogen

are found in compounds containing such strongly

molecules have a parallel spin, para- an antiparallel

electronegative atoms as nitrogen, oxygen, and fluo-

spin. By cooling to liquid air temperature and use of

rine. They play an important part in the bonding of

a ferric oxide gel catalyst, the normal equilibrium of

cellulosic compounds, e.g., in the paper industry,

3 ortho- to 1 para- is displaced and para-hydrogen

and occur also in many complex structures of bio-

may be isolated. It is being produced with less than 5

chemical importance, e.g., adenine-uracil linkage in

ppm impurities.

DNA.

hydrogenated fish oil. hydrogen bromide.

CAS: 8016-14-6. CAS: 10035-10-6. HBr.

Properties: Oil. Mp: >32°. Properties: Colorless gas. D 2.71 (air

1.00), fp

Use: Food additive. −86C, bp −66.4C, specific volume 4.8 cu ft/lb (70F,

667 HYDROGEN PEROXIDE

1 atm). Soluble in water and alcohol. Nonflamm- nium.

able.

See hydrofluoric acid.

Derivation: (1) By passing hydrogen with bromine

vapor over warm platinum sponge which acts as a

hydrogen hexafluorosilicate. See fluosilicic

catalyst; (2) As a by-product in the bromination of

acid.

organic compounds.

Grade: Up to 99.8% min purity.

hydrogen iodide.

Hazard: Toxic by inhalation, strong irritant to eyes

CAS: 10034-85-2. HI.

and skin. TLV: ceiling 3 ppm.

Properties: Colorless gas. Bp −35C, fp −51C, fumes

Use: Organic synthesis, makes bromides by direct

in moist air, d 5.2 (25C). Freely soluble in water.

reaction with alcohols, pharmaceutical intermedi-

Nonflammable.

ate; alkylation and oxidation catalyst, reducing

Hazard: Strong irritant. Poison.

agent.

Use: Making hydriodic acid.

See hydrobromic acid.

hydrogen ion concentration. See pH.

hydrogen chloride.

hydrogenolysis. (destructive hydrogenation).

CAS: 7647-01-0. HCl.

A type of hydrogenation reaction in which molecu-

Properties: Colorless gas or fuming liquid; suffocat-

lar cleavage of an organic compound occurs with

ing odor. D 1.268 (air

1.00), fp −114C, bp −85C,

addition of hydrogen to each portion. An important

specific volume 10.9 cu ft/lb (21.1C, 1 atm). Very

application is hydrocracking (hydrogenative split-

soluble in water; soluble in alcohol and ether. Non-

ting) of large organic molecules, with formation of

flammable.

fragments that react with hydrogen by use of cata-

Derivation: (1) By-product of organic chlorination

lysts and high temperatures. Hydrogenolysis of coal

reactions (approximately 90%); (2) reaction of sodi-

to gaseous and liquid fuels was used in Germany in

um chloride and sulfuric acid; (3) burning hydrogen

the 1940s; a similar method (Oil/Gas Process) is

in an atmosphere of chlorine in absence of air.

under development in the U.S. The German process

Hazard: Toxic by inhalation, strong irritant to eyes

used pulverized coal made into a paste with heavy

and skin. TLV: ceiling 5 ppm.

oil and a metallic catalyst. The mixture plus the

Use: Production of vinyl chloride from acetylene and

necessary hydrogen was subjected to 300–700 atm

alkyl chlorides from olefins, hydrochlorination (see

at approximately 500C. The coal was converted into

rubber hydrochloride), polymerization, isomeriza-

heavy oil, distillable oil, gasoline, and hydrocarbon

tion, alkylation, and nitration reactions.

gases. Large quantities of hydrogen are necessary.

See hydrochloric acid.

See gasification; hydrogenation.

hydrogen cyanide. See hydrocyanic acid.

hydrogen overvoltage. The difference be-

tween actual cathode potential for hydrogen evolu-

hydrogen dioxide. See hydrogen peroxide.

tion and the equilibrium (theoretical) potential of

hydrogen in the same electrolyte.

hydrogen electrode. See electrode, hy-

drogen.

hydrogen peroxide.

CAS: 7722-84-1. H

(molecular formula);

hydrogen fluoride. H−O−O−H (structural formula).

CAS: 7664-39-3. HF. Properties: (pure anhydrous) density of solid, 1.71

Properties: Colorless, fuming gas or liquid. Very g/cc, density of liquid 1.450 g/cc at 20C, viscosity,

soluble in water. The liquid and gas consist of asso- liquid 1.245 cP, surface tension 80.4 dynes/cm at

ciated molecules. The vapor density corresponds to 20C, fp −0.41C, bp 150.2C. Soluble in water and

hydrogen fluoride only at high temperatures. Fp alcohol. (Solutions): pure hydrogen peroxide solu-

−83C, bp 19.5C, d (liquid) 0.988 (14C), sp vol 17 cu tions, completely free from contamination, are high-

ft/lb (21.1C, 1 atm). Nonflammable. ly stable; a low percentage of an inhibitor such as

Derivation: Distillation from the reaction product of acetanilide or sodium stannate, is usually added to

calcium fluoride and sulfuric acid, also from fluosil- counteract the catalytic effect of traces of impurities

icic acid. such as iron, copper, and other heavy metals. A

Grade: To 99.9% min purity. relatively stable sample of hydrogen peroxide typi-

Hazard: Toxic by ingestion and inhalation, strong cally, decomposes at the rate of approximately 0.5%

irritant to eyes, skin, and mucous membranes. TLV: per year at room temperature.

ceiling 3 ppm. Derivation: (1) autoxidation of an alkyl anthrahy-

Use: Catalyst in alkylation, isomerization, condensa- droquinone such as the 2-ethyl derivative in a cyclic

tion, dehydration, and polymerization reactions; continuous process in which the quinone formed in

fluorinating agent in organic and inorganic reac- the oxidation step is reduced to the starting material

tions; production of fluorine and aluminum fluoride; by hydrogen in the presence of a supported palladi-

additive in liquid rocket propellants; refining of ura- um catalyst; (2) by electrolytic processes in which

668HYDROGEN PHOSPHIDE

aqueous sulfuric acid or acidic ammonium bisulfate ture and pressure; (3) as a by-product of petroleum

refining.

is converted electrolytically to the peroxydisulfate,

Grade: Technical 98.5%, purified 99.5% min, CP.

which is then hydrolyzed to form hydrogen perox-

Hazard: Highly flammable, dangerous fire risk, ex-

ide; (3) by autoxidation of isopropyl alcohol. Meth-

plosive limits in air 4.3–46%. Toxic by inhalation,

od (1) is most widely used.

strong irritant to eyes and mucous membranes.

Grade: USP (3%), technical (3, 6, 27.5, 30, 35, 50,

TLV: TWA 10 ppm; STEL 15 ppm.

and 90%), FCC. Most common commercial

Use: Purification of hydrochloric acid and sulfuric

strengths are 27.5, 35, 50, and 70%.

acid, precipitating sulfides of metals, analytical re-

Hazard: Dangerous fire and explosion risk, strong

agent, source of sulfur and hydrogen.

oxidizing agent. Concentrated solutions are highly

toxic and strongly irritating. TLV: TWA 1 ppm;

animal carcinogen.

hydrogen tellurate. See telluric acid.

Use: Bleaching and deodorizing of textiles, wood

pulp, hair, fur, etc.; source of organic and inorganic

hydrogen telluride. H

Te.

peroxides; pulp and paper industry; plasticizers;

Properties: Colorless gas. D (liquid): 2.57 (−20C),

rocket fuel; foam rubber; manufacture of glycerol;

fp −49C, bp −2C. Soluble in water but unstable;

antichlor; dyeing; electroplating; antiseptic; labora-

soluble in alcohol and alkalies.

tory reagent; epoxidation, hydroxylation, oxidation,

Hazard: See hydrogen selenide.

and reduction; viscosity control for starch and cellu-

lose derivatives; refining and cleaning metals;

“Hydroholac” [Rohm & Haas]. TM for

bleaching and oxidizing agent in foods; neutralizing

plasticized nitrocellulose lacquer emulsions, includ-

agent in wine distillation; seed disinfectant; substi-

ing clear finishes, binders and colors. Produce flexi-

tute for chlorine in water and sewage treatment.

ble, lacquer-type, cleanable leather finishes from

See “Kastone” [Du Pont].

aqueous systems.

Use: Finishes on glove, garment, handbag and shoe

leather.

hydrogen phosphide. See phosphine.

␣-hydro-␻-hydroxypoly(oxy(methyl-1,2-

hydrogen, phosphoretted. See phosphine.

ethanediyl)) ether with bis((2-

(hydroxyethyl)amino)methyl)phenol (3:1).

hydrogen selenide.

CAS: 68909-26-2.

CAS: 7783-07-5. H

Se.

Hazard: A moderate eye irritant.

Properties: Colorless gas. Bp −42C; fp −64C; d 2.00

(air

1). Soluble in water, carbon disulfide, phos-

hydrol. See tetramethyldiaminobenzhydrol.

gene.

Grade: 98% pure.

hydrolase. (hydrase). An enzyme which cata-

Hazard: Dangerous fire and explosion risk; reacts

lyzes the removal of water from the substrate.

violently with oxidizing materials. Toxic by inhala-

See enzyme.

tion, strong irritant to skin, damaging to lungs and

liver. TLV: 0.05 ppm (as selenium).

“Hydrolin” [Olin]. TM for ammonium nitrate

Use: Preparation of metallic selenides and organose-

preparations.

lenium compounds; in doping as mix for preparation

Hazard: See ammonium nitrate.

of semiconductor materials containing controlled

Use: Bleaching agent for pulp, clay, and mineral

amounts of significant impurities.

processing.

hydrogen slush. A mixture of solid and liquid

hydroliquefaction. Production of liquid hydro-

hydrogen at the hydrogen triple point 13.8K and

carbon fuels by hydrogenation of coal.

1.02 psia. It is denser and less hazardous than liquid

See gasification; Oil/Gas Process.

hydrogen.

hydrolube. A water-glycol base noncombustible

hydrogen sodium selenite. See selenious

hydraulic fluid.

acid, monosodium salt.

hydrolysis. A chemical reaction in which water

hydrogen sulfide. (sulfuretted hydrogen). reacts with another substance to form two or more

CAS: 7783-06-4. H

S. new substances. This involves ionization of the wa-

Properties: Colorless gas; offensive odor. D 1.189 ter molecule as well as splitting of the compound

(air

1.00), fp −83.8C, bp −60.2C, sp vol 11.23 cu hydrolyzed, e.g., CH

COOC

O →

ft/lb (21.1C, 1 atm), autoign temp 500F (260C). CH

COOH + C

OH. Examples are conversion of

Soluble in water and alcohol. starch to glucose by water in the presence of suitable

Derivation: (1) By the action of dilute sulfuric acid catalysts; conversion of sucrose (cane sugar) to glu-

on a sulfide, usually iron sulfide; (2) by direct union cose and fructose by reaction with water in the pres-

of hydrogen and sulfur vapor at a definite tempera- ence of an enzyme or acid catalyst; conversion of

669 HYDROQUININE

natural fats into fatty acids and glycerol by reaction (515.5C). Soluble in water, alcohol, and ether. Com-

with water in one process of soap manufacture; and bustible.

reaction of the ions of a dissolved salt to form vari- Derivation: Aniline is oxidized to quinone by man-

ous products, such as acids, complex ions, etc. ganese dioxide and is then reduced to hydroquinone.

Grade: Technical, photographic.

Hazard: Toxic by ingestion and inhalation, irritant.

hydrolyzed vegetable proteins. See “Hy-

TLV: TWA 2 mg/m

; animal carcinogen.

drotriticum” [Croda].

Use: Photographic developer (except color film); dye

intermediate; inhibitor; stabilizer in paints and var-

hydrometer. Device for measuring the density

nishes, motor fuels, and oils; antioxidant for fats and

of liquids.

oils; inhibitor of polymerization; skin hyperpigmen-

See Baume´.

tation.

hydronium ion. An ion (H

) formed by the

hydroquinone benzyl ether. See p-benzy-

transfer of a proton (hydrogen nucleus) from one

loxyphenol.

molecule of water to another; a companion ion

(OH

−

) is also formed, the reaction is 2H

O → H

hydroquinone dibenzyl ether.

−

. Formation of such ions is statistically rare,

CAS: 103-16-2. C

OCH

resulting from the interaction of water molecules in

Properties: Tan powder. Mp 119C (min). Purity

a ratio of 1:556 million.

90% (min). Insoluble in water; soluble in acetone,

benzene, and chlorobenzene. Combustible.

hydropathy index. A scale that expresses the

Use: Solvent; perfumes, soap, plastics, and pharma-

relative hydrophobic and hydrophilic tendencies of

ceuticals.

amino acid R groups. Used to predict membrane-

spanning regions.

hydroquinone di-n-butyl ether. (1,4-dibu-

toxybenzene). C

[O(CH

)

]

hydroperoxide. An organic peroxide having the

Properties: White flakes; no appreciable odor. Mp

generalized formula ROOH. An example is ethyl

45–46C; bp 124C (1.3 mm Hg), 158C (15.0 mm

hydroperoxide (C

OOH). Methyl and ethyl hy-

Hg). Insoluble in water; soluble in benzene, acetone,

droperoxides are unstable and thus are strong oxi-

ethyl acetate, and alcohol. Combustible.

dizing agents and explosion hazards; those of higher

molecular weight are more stable. Hydroperoxides

hydroquinone diethyl ether. (1,4-diethoxy-

can be derived by oxidation of saturated hydrocar-

benzene). C

(OC

)

bons, or by alkylating hydrogen peroxide in a

Properties: White granular solid with anise-like

strongly acidic environment. They are used as poly-

odor. Mp 71–72C, bp 246C. Neither boiling caustic

merization initiators.

nor acid solution causes any hydrolysis. Absorbs

UV light. Insoluble in water; soluble in benzene,

hydrophilic. Having a strong tendency to bind or

acetone, ethyl acetate, and alcohol. Combustible.

absorb water, which results in swelling and forma-

tion of reversible gels. This property is characteristic

hydroquinone di(␤-hydroxyethyl) ether.

of carbohydrates, such as algin, vegetable gums,

(p-di-[2-hydroxyethoxy]benzene).

pectins, and starches, and of complex proteins such

(OC

OH)

as gelatin and collagen.

Properties: White solid. Mp 99C, bp 185–200C (0.3

mm Hg). Slightly soluble in water and most organic

hydrophobic. (1) Antagonistic to water; incapa-

solvents; miscible with water at 80C. Combustible.

ble of dissolving in water. This property is charac-

Use: Preparation of polyester, polyolefins, polyure-

teristic of all oils, fats, waxes, and many resins, as

thanes, and hard waxy resins, organic synthesis.

well as of finely divided powders like carbon black

and magnesium carbonate.

hydroquinone dimethyl ether. (1,4-dime-

(2) The association of nonpolar groups or com-

thoxybenzene; DMB; dimethyl hydroquinone).

pounds with each other in aqueous systems due to

CAS: 654-42-2. C

(OCH

)

their insolubility in water.

Properties: White flakes with sweet clover odor. Bp

213C, mp 56C, d 1.0293 (65C), viscosity 1.04 cP

hydroponics. See nutrient solution.

(65C), dielectric constant 2.8, absorbs UV light in

range 2800–3000A

. Soluble in benzene and alcohol;

hydroquinol. See hydroquinone.

insoluble in water. Combustible.

Use: Weathering agent in paints and plastics, fixative

in perfumes, dyes, resin intermediate, cosmetics,

hydroquinone. (quinol; hydroquinol; p-dihy-

especially suntan preparations, flavoring.

droxybenzene).

CAS: 123-31-9. C

(OH)

Properties: White crystals. D 1.330, mp 170C, bp

hydroquinine mono-n-butyl ether.

285C, flash p 329F (165C), autoign temp 960F CH

(CH

)

OH.

670HYDROQUINONE

Properties: White flakes. Mp 64–65C; bp 115C (1.4

hydroxocobalamin. (USAN) (␣[5,6-dime-

mm Hg). Insoluble in water; soluble in benzene, thylbenzimidazolyl]hydroxocobaltamide).

acetone, ethyl acetate, and alcohol. Combustible. C

CoN

P. A form of vitamin B

Use: Medicine.

See vitamin B

hydroquinone monoethyl ether. (4-ethoxy-

phenol). C

OH.

hydroxyacetal. See hydroxycitronellal di-

Properties: White solid. Mp 63–65C, bp 246–247C.

methyl acetal.

Slightly soluble in water; soluble in benzene, ace-

tone, ethyl acetate, and alcohol. Combustible.

p-hydroxyacetanilide. See p-acetylamino-

Use: See hydroquinone monomethyl ether.

phenol.

hydroquinone monomethyl ether. (4-me-

hydroxyacetic acid. (glycolic acid). CH

OH-

thoxyphenol; p-hydroxyanisole).

COOH.

CAS: 150-76-5. CH

OH.

Properties: Colorless crystals, deliquescent. Mp

Properties: White, waxy solid. Mp 52.5C, bp 243C,

78–79C, bp decomposes. Soluble in water, alcohol,

d 1.55 (20/20C). Slightly soluble in water; readily

and ether; available commercially as a 70% solu-

soluble in benzene, acetone, ethanol, and ethyl ace-

tion, light straw-colored liquid, odor like burnt sug-

tate. Combustible.

ar, d 1.27, mp 10C. Combustible.

Hazard: TLV: TWA 5 mg/m

Derivation: From chloroacetic acid by reaction with

Use: Manufacture of antioxidants, pharmaceuticals,

sodium hydroxide, or by reduction of oxalic acid.

plasticizers, dyestuffs; stabilizer for chlorinated hy-

Occurs naturally in sugar cane syrup.

drocarbons and ethyl cellulose, inhibitor for acrylic

Grade: Technical 70% solution, pure crystals.

monomers and acrylonitriles, UV inhibitor.

Use: Leather dyeing and tanning; textile dyeing; cle-

aning, polishing, and soldering compounds; copper

hydrosilicofluoric acid. See fluosilicic acid.

pickling; adhesives; electroplating; breaking of pe-

troleum emulsions; chelating agent for iron; chemi-

cal milling; pH control.

hydrosolvation. Solvent extraction of coal (con-

taining up to 5% sulfur) under hydrogen pressure

with the use of a catalyst such as zinc chloride;

hydroxyacetone. See hydroxy-2-propanone.

pressures from 1000–2000 psi are necessary for

suitable conversion. This process offers a means of

o-hydroxyacetophenone. C

(OH)COCH

deriving fuel oil and petrochemical feedstocks di-

Properties: Greenish-yellow liquid with minty odor.

rectly from coal.

D 1.1307 (20.8C), bp 213C (717 min), refr index

1.5580 (20C). Slightly soluble in water. Combus-

tible.

hydrosulfite. See sodium hydrosulfite.

␣-hydroxy acids. (fruit acids; alpha-hydroxy

hydrosulfite-formaldehyde. One of several

acids). Said to diminish fine skin lines and pigmen-

mixtures of sodium formaldehyde hydrosulfite and

tation spots and to stimulate collagen to allow the

sodium formaldehyde bisulfite used as discharges

skin to repair itself.

and stripping or reducing agents in dyeing and other

textile operations. In some cases the zinc derivatives

2-hydroxyadipaldehyde.

are used. Derivation is by the action of formalde-

OHCCH

OCHO.

hyde on aqueous sodium hydrosulfite or from zinc,

Properties: (25% aqueous solution) d 1.066 (20C),

formaldehyde, sulfur dioxide, and sodium hy-

bp 37C (50 mm Hg), vap press 17 mm Hg (20C), fp

droxide.

−3.5C, pH approximately 3.0. Combustible.

Hazard: Toxic by ingestion.

Hazard: Toxic by inhalation.

Use: Intermediate, insolubilizing agent for proteins

hydrothermal energy. See geothermal en-

and polyhydroxy materials, cross-linking agent for

ergy.

polyvinyl compounds, shrinkage control agent (tex-

tiles).

“Hydrotriticum” [Croda]. (hydrolyzed veg-

etable proteins). TM for wheat protein.

␤-hydroxyalanine. See serine.

Use: For hair waving systems, shampoos, condition-

ers, and skin care products.

5-hydroxy-3-(␤-aminoethyl)indole. See

serotonin.

hydrotrope. A chemical which has the property

of increasing the aqueous solubility of various

n-hydroxy p-aminooctanoylphenone.

slightly soluble organic chemicals. CAS: 253883-44-2. mf: C

Use: Formulation of liquid detergents. Hazard: A poison.

671 HYDROXY-␤-CAROTENE

p-hydroxyamphetamine hydrochloride. 2-hydroxy-1

′

-benzocarbazole-3-carboxylic

CAS: 6078-07-5. mf: C

NO•ClH. acid. C

Hazard: A reproductive hazard.

Properties: A four-ring structure, light-green pow-

der. Mp 315–320C. Soluble in ethanol and acetone;

3-␤-hydroxyandrosten-17-one acetate.

insoluble in water.

CAS: 1239-31-2. mf: C

Use: Manufacture of dye intermediates and other

Hazard: Low toxicity by ingestion. A reproductive

organic chemicals.

hazard.

Use: Hormone.

m-hydroxybenzoic acid.

CAS: 99-06-9. C

(OH)COOH.

hydroxyaniline. See aminophenol.

Properties: White powder. Mp 200C. Soluble in

water and hot alcohol.

o-hydroxyanisole. See guaiacol.

Use: Intermediate for plasticizers, resins, light stabil-

iziers, petroleum additives, pharmaceuticals.

p-hydroxyanisole. See hydroquinone mono-

methyl ether.

o-hydroxybenzoic acid. See salicylic acid.

9-hydroxyanthracene. See anthranol.

p-hydroxybenzoic acid.

CAS: 99-96-7. C

(OH)COOH•H

Properties: Colorless crystals. D 1.46, mp 210C.

hydroxyapatite. Ca

(PO

)

(OH)

. The major

Soluble in alcohol and ether; partially soluble in

constituent of bone and tooth mineral. It is finely

water.

divided, crystalline, nonstoichiometric material rich

Derivation: Interaction of p-aminobenzoic acid and

in surface ions (carbonate, magnesium, citrate)

nitrous acid.

which are readily replaced by fluoride ion, thus

Use: Intermediate, synthetic drugs, food preservative

affording protection to the teeth.

(up to 0.1%) (approved by FDA). Its methyl, propyl,

See fluoridation; calcium phosphate tribasic.

and butyl esters are preservatives for cosmetics and

pharmaceuticals.

p-hydroxyazobenzene-p-sulfonic acid.

HOC

NNC

2-hydroxybenzophenone. C

COC

OH.

Properties: Orange-red crystals. Very soluble in

Properties: A solid. Mp 41C, bp 210C (27 mm Hg).

water.

Insoluble in water; soluble in alcohol.

Use: Analytical reagent, precipitant for numerous

Use: UV absorber in plastics.

organic bases.

4-hydroxybenzothiophene.

m-hydroxybenzaldehyde.

CAS: 3610-02-4. mf: C

OS.

CAS: 100-83-4. HOC

CHO.

Hazard: A poison.

Properties: Orange-pink crystals. Mp 101.5C.

Slightly soluble in cold water; very soluble in hot

o-hydroxybenzyl alcohol. See salicyl al-

water and aromatic hydrocarbons.

cohol.

Hazard: Toxic by ingestion.

Use: Intermediate for dyes, plastics, pharmaceuti-

␤-hydroxybutyraldehyde. See aldol.

cals, and bactericides; color reagent for Schiff’s

reagent, sensitizing agent in photographic emul-

sions.

p-hydroxybutyranilide. (4

′

-hydroxybutyrani-

lide). C

Properties: Acicular crystals. Mp 138C. Soluble in

o-hydroxybenzaldehyde. See salicylal-

alcohol; partially soluble in hot water.

dehyde.

Use: Antioxidant for petroleum products.

p-hydroxybenzaldehyde.

␤-hydroxybutyric acid.

CAS: 123-08-0. HOC

CHO.

CAS: 502-85-2. CH

CH(OH)CH

COOH.

Properties: Viscid yellow mass. Mp 48–50C, bp

130C (12 mm Hg). Very soluble in water, alcohol

and ether.

Derivation: Interaction of acetoacetic acid and sodi-

Properties: Colorless needles. D 1.129, mp 116C

um amalgam.

(sublimes). Soluble in alcohol, ether, or hot water.

Grade: Technical, reagent.

Use: Pharmaceuticals.

Use: Intermediate.

o-hydroxybenzamide. See salicylamide.

2-hydroxycamphane. See borneol.

hydroxybenzene. See phenol. hydroxy-␤-carotene. See cryptoxanthin.

6723-␤-HYDROXYCHOLESTANE

3-␤-hydroxycholestane. See dihydrocholest- p-hydroxydiphenylamine. (anilinophenol).

erol. CAS: 122-37-2. C

NHC

OH. Gray solid leaf-

lets, mp approximately 70C, purity 98% (min), bp

330C. Insoluble in water; soluble in alcohol, ether,

hydroxycitronellal. (citronellal hydrate; 3,7-

acetone, chloroform, alkali, and benzene.

dimethyl-7-hydroxyoctenal).

Hazard: Irritant.

CAS: 107-75-5.

(CH

)

C(OH)(CH

)

CH(CH

)CH

CHO.

7-hydroxy-2-(dipropylamino)tetraline.

Properties: Viscous, colorless or faintly yellow liq-

CAS: 74938-11-7. mf: C

NO.

uid; sweet lily-type odor. D 0.925–0.930 (15C), refr

Hazard: A poison.

index 1.448–1.450 (20C), optical rotation (Java

type) +9 to +10.5 degrees, boiling range 94–96C (1

8-hydroxy-2-(di-n-propylamino)tetraline.

mm Hg). Soluble in alcohol (50%), fixed oils; slight-

CAS: 78950-78-4. mf: C

NO.

ly soluble in water, glycerol and mineral oil. Com-

Hazard: A poison.

bustible.

Derivation: From citronellal (Java citronella or Eu-

1-hydroxyestradiol.

calyptus citriodora).

CAS: 4147-05-1. mf: C

Grade: Perfume, FCC.

Hazard: A reproductive hazard.

Use: Perfumery (fixative, muguet odor), flavoring,

Use: Hormone.

soap and cosmetic fragrances.

4-hydroxyestrone.

hydroxycitronellal dimethyl acetal. (hy-

CAS: 3131-23-5. mf: C

droxyacetal).

Hazard: A reproductive hazard.

(CH

)

C(OH)(CH

)CH(CH

)CH

CH(OCH

)

Use: Hormone.

Properties: Colorless liquid; light floral odor. D

0.925–0.930 (25/25C), refr index 1.4410–1.4440

2-hydroxyethanesulfonic acid. See iseth-

(20C). Soluble in most fixed oils, mineral oil, pro-

ionic acid.

pylene glycol; insoluble in glycerol. Combustible.

Grade: Perfume, FCC.

hydroxyethylacetamide. See n-acetylethano-

Use: Flavoring agent in foods, perfumery.

lamine.

hydroxycitronellal-methyl anthranilate

2-hydroxyethyl acrylate. (HEA). A func-

Schiff base. C

tional monomer for the manufacture of thermoset-

Properties: Linden–orange-flower odor; yellow, ho-

ting acrylic resins.

neylike, viscous liquid. Stable, refr index

1.5350–1.5460 (20C), flash p 206F (96.6C) (TCC).

2-hydroxyethylamine. See ethanolamine.

Soluble in two parts of 70% alcohol, one part of 80%

alcohol. Combustible.

n-(2-hydroxyethyl)ammonium

Use: Perfumery.

benzothiazole-2-thiolate.

CAS: 5902-85-2. mf: C

•C

NO.

17-hydroxycorticosterone. See hydrocorti-

Hazard: Moderately toxic by ingestion. A severe eye

sone.

irritant.

trans-1-(4-hydroxycyclohexyl)-4-(4-

2-hydroxyethyl carbamate.

fluorophenyl)-5-(2-methoxypyrimidin-4-

CAS: 589-41-3. H

NCOOCH

OH.

yl)imidazole.

Properties: Crystalline, deliquescent solid. Mp 43C,

CAS: 193551-21-2. mf: C

bp 130–135C (1 mm Hg), d 1.2852 g/cc (20C), flash

Hazard: A poison by ingestion.

p 370F (187.7C). Miscible with water; soluble in

alcohol and acetone; insoluble in benzene and chlo-

3-hydroxy-p-cymene. See thymol.

roform. Combustible.

Use: Chemical intermediate, especially for wash-

1-hydroxy-2,4-diamylbenzene. See diamyl

and-wear cotton finishing agents.

phenol.

2-hydroxyethyl dibutyl phosphate.

6-hydroxy-3,7-dimethyloctanoic acid

CAS: 130525-77-8. mf: C

lactone. mf: C

Hazard: Moderately toxic by ingestion and skin con-

Properties: Colorless solid; maple syrup odor. D:

tact. A mild skin and eye irritant.

0.966, refr index: 1.457−1.461. Sol in alc; very sltly

sol in water.

hydroxyethylcellulose. (“Cellosize”).

Use: Food additive.

Properties: Nonionic, water-soluble cellulose ether;

white, free-flowing powder; insoluble in organic

hydroxydiphenyl. See phenylphenol. solvents; soluble in hot or cold water; stable in con-

673 13-HYDROXYGERMACRONE

centrated salt solutions; grease and oil resistant. water; soluble in common organic solvents. An in-

hibitor is usually added to solutions to prolong shelf

Combustible.

life. The 30% solution is made with xylene.

Use: Thickening and suspending agent; stabilizer for

Hazard: 30% grade (with xylene): Flammable, mod-

vinyl polymerization; retards evaporation of water

erate fire risk.

in cements, mortars, and concrete; binder in ceramic

Grade: 30%, 96%.

glazes, films, and sheeting; protective colloid; paper

Use: Acrylic resins, binder for nonwoven fabrics,

and textile sizing; secondary petroleum recovery.

enamels.

n-(2-hydroxyethyl)-5,8,11,14-

eicosatetraenamide (all-z)-.

n-(2-hydroxyethyl)-n-methyl-2-nitro-1h-

CAS: 94421-68-8. mf: C

imidazole-1-acetamide.

Hazard: A reproductive hazard.

CAS: 197004-63-0.

Properties: 2-Nitroimidazole hypoxic cell radiosen-

hydroxyethylethylenediamine. (aminoethy-

sitizer mf: C

lethanol amine).

Hazard: A poison.

CAS: 111-41-1. NH

NHCH

OH.

Properties: Hygroscopic liquid; mild ammoniacal

N-hydroxyethylmorpholine. See n-morpho-

odor. D 1.0304 (20/20C), bp 243.7C, vap press 0.01

line ethanol.

mm Hg (20C), flash p 275F (135C), bulk d 8.6 lb/gal

(20C). Soluble in water. Combustible.

N-hydroxyethyl piperazine.

Use: Textile finishing compounds (antifuming

CAS: 103-76-4.

agents, dyestuffs, cationic surfactants), resins, rub-

ber products, insecticides, and certain medicinals.

HOCH

❘

NHCH

❘

hydroxyethylethylenediaminetriacetic acid.

Properties: Liquid. D 1.0614 (20/20C), bp 246.3C,

(HEDTA).

fp −10C, flash p 255F (124C). Miscible with water.

CAS: 150-39-0. C

Combustible.

Properties: Solid. Mp 159C. Soluble in water and

Use: Intermediate for pharmaceuticals, anthelmin-

methanol.

tics, surface-active agents, and synthetic fibers.

Use: Chelating compound.

N-2-hydroxyethylpiperidine. See 2-piperidi-

n-(2-hydroxyethyl)ethyleneimine. See 1-

noethanol.

aziridineethanol.

(2-hydroxyethyl)-2-propenenitrile.

1-(2-hydroxyethyl)-2-n-heptadecenyl-2-

CAS: 69521-64-8. mf: C

NO.

imidazoline. C

O. A liquid cationic de-

Hazard: A poison by ingestion and skin contact. A

tergent.

severe eye irritant.

Use: Corrosion inhibitor, acid-stable emulsifier.

hydroxyethylpyrrolidine. See 1-pyrrolidi-

␤-hydroxyethylhydrazine. (ethanolhydra-

neethanol.

zine).

CAS: 109-84-2. HOCH

NHNH

Properties: Colorless, slightly viscous liquid. D 1.11

hydroxyethyltrimethylammonium

(20C), fp −70C, boiling range 145–153C (25 mm

bicarbonate. (choline bicarbonate).

Hg), flash p 224F (106.6C). Miscible with water;

(CH

)

NCH

OH•HCO

soluble in lower alcohols; slightly soluble in ether.

Properties: Colorless liquid. D 1.0965 (25/4C), fp

Combustible.

−21.3C, refr index 1.3967 (25C). Miscible with

Grade: 70%.

water.

Hazard: Moderate fire risk. Irritant.

Grade: Industrial grade is a 44–46% aqueous solu-

Use: Intermediate, plant growth regulator, flowering

tion of a mixture of carbonate and bicarbonate.

inducer for pineapples.

Use: Alkaline catalyst, intermediate for choline salts

and surfactants.

2-hydroxy-2-ethyl-3-isobutyl-9,10-

dimethoxy-1,2,3,4,6,7-

␤-hydroxyethyltrimethylammonium

hexahydrobenzo(a)chinolizin.

hydroxide. See choline.

CAS: 303-75-3. mf: C

Hazard: A poison.

1-hydroxyfenchane. See fenchyl alcohol.

2-hydroxyethyl methacrylate. (HEMA).

CAS: 868-77-9. C

. 13-hydroxygermacrone.

Properties: Clear, mobile liquid. D 1.064 (77/60F), CAS: 213908-53-3. mf: C

fp −12C, refr index 1.4505 (25C). Miscible with Hazard: A poison by ingestion.

6745-HYDROXY-1H-INDOLE-3

5-hydroxy-1h-indole-3-ethanol. fication agent for aldehydes and ketones, chemical

CAS: 154-02-9. mf: C

. synthesis, textile chemical, oxidation inhibitor for

Hazard: A reproductive hazard. fatty acids, catalyst, biological and biochemical re-

search, making oximes for paints and varnishes,

rustproofing, nondiscoloring short-stopper for syn-

m-hydroxyisopropylphenyl-n-

methylcarbamate. thetic rubbers, unhairing hides.

CAS: 17710-63-3. mf: C

Hazard: A poison.

hydroxylammonium acid sulfate. See hy-

Use: Agricultural chemical.

droxylamine acid sulfate.

4-hydroxy-2-keto-4-methylpentane. See

hydroxylammonium chloride. See hydrox-

diacetone alcohol.

ylamine hydrochloride.

hydroxylamine. (oxammonium).

hydroxylammonium sulfate. See hydroxyl-

CAS: 7803-49-8. NH

OH.

amine sulfate.

Properties: Colorless crystals. D 1.227, mp 33C, bp

70C (60 mm Hg), the free base is unstable. Soluble

hydroxylated lecithin.

in alcohol, acids, and cold water.

Properties: Light yellow liquid to paste; characteris-

Derivation: By decomposing hydroxylamine hydro-

tic odor. Moderatelly sol in water.

chloride or sulfate with a base and distilling in

Use: Food additive.

vacuo.

Hazard: Decomposes rapidly at room temperature,

hydroxyl group. The univalent group −OH,

violently when heated, detonates in flame-heated

occurring in many inorganic compounds that ionize

testtube. Irritant to tissue.

in solution to yield OH

−

radicals. Also the character-

Use: Reducing agent, organic synthesis.

istic group of alcohols.

See -ol.

hydroxylamine acid sulfate. (hydroxylam-

monium acid sulfate; hydroxylamine hemisul-

o-hydroxymercuriobenzoic acid.

fate; HAS). NH

OH•H

CAS: 14066-61-6. mf: C

HgO

Properties: White to brown crystalline solid. Bulk d

Properties: IDLH 10 mg/m

(as Hg).

15–16 lb/gal (20C), mp indefinite (decomposes), pH

Hazard: A poison. TWA 0.1 mg(Hg)/m

(skin)

of 0.1 molar aqueous solution 1.6. Very hygroscop-

ic; soluble in water and methanol; slightly soluble in

p-hydroxymercuribenzoic acid.

alcohol.

CAS: 1126-48-3. mf: C

HgO

Use: Reducing agent, photographic developer, puri-

Properties: IDLH 10 mg/m

(as Hg).

fication agent for aldehydes and ketone, synthesis of

Hazard: A poison. TWA 0.1 mg(Hg)/m

(skin)

dyes and pharmaceuticals; rubber chemicals, re-

agent.

N-(7-hydroxyl-1-naphthyl)acetamide. (1-

acetylamino-7-naphthol). C

(OH)NHCOOH

hydroxylamine hydrochloride. (hydroxy- A granular paste.

lammonium chloride). Use: Chemical intermediate.

CAS: 5470-11-1. NH

OH•HCl.

Properties: Colorless, hygroscopic crystals. D 1.67

hydroxymercurichlorophenol. (2-chloro-4-

(17C). Soluble in water, glycerol, and alcohol; insol-

[hydroxymercuri]phenol). C

Cl(HgOH)(OH).

uble in ether; mp 152C (decomposes); pH of 0.1

Properties: Insoluble in water and common organic

molar aqueous solution 3.4.

solvents; soluble in solutions of acids and alkalies

Derivation: Reduction of ammonium chloride, fre-

with the formation of salts.

quently by electrolysis.

Hazard: Toxic by ingestion and inhalation, strong

Hazard: Toxic by ingestion, strong irritant to tissue.

irritant to eyes and skin, use may be restricted. TLV:

Use: Organic synthesis, photographic developer,

0.01 (Hg) mg/m

medicine, controlled reduction reactions, nondisco-

Use: Seed disinfectant and fungicide.

loring short-stopper for synthetic rubbers, antioxi-

dant for fatty acids.

hydroxymercuricresol.

(HgOH)(OH).

Hazard: Toxic by ingestion and inhalation, strong

hydroxylamine sulfate. (HS; hydroxylam-

irritant to eyes and skin, use may be restricted. TLV:

monium sulfate).

0.01 (Hg) mg/m

CAS: 10039-54-0. (NH

OH)

•H

Use: Pesticide.

Properties: Colorless crystals. Mp 177C (decom-

poses). Solution has a corrosive action on the skin.

Soluble in water, slightly soluble in alcohol.

hydroxymercurinitrophenol.

Hazard: Irritant to tissue. C

(HgOH)(OH).

Use: Reducing agent, photographic developer, puri- Hazard: Toxic by ingestion and inhalation, strong

675 5-HYDROXY-1,4-NAPHTHO

irritant to eyes and skin, use may be restricted. TLV:

2-(2

′

-hydroxy-5

′

-methylphenyl)

0.01 (Hg) mg/m

. benzotriazole. HOC

(CH

Use: Pesticide. Properties: Off-white, crystalline powder. Mp

129–130C, bp 225C (10 mm Hg). Insoluble in wa-

ter; soluble in methylethyl ketone, methyl methacry-

2-hydroxymesitylene. See mesitol.

late.

Use: Protector against UV radiation, thermal stabiliz-

2-hydroxymestranol.

er, antioxidant, chelation of metals.

CAS: 26011-40-5. mf: C

Hazard: A reproductive hazard.

␣-hydroxy-␣-methylpropiophenone.

Use: Hormone.

CAS: 7473-98-5. mf: C

Hazard: Moderately toxic by ingestion.

6-(hydroxymethyl)acylfulvene.

CAS: 158440-71-2. mf: C

3-hydroxy-2-methyl-1,4-pyrone. See

Hazard: A poison.

maltol.

2-hydroxy-3-methylbenzoic acid. See cre-

2-hydroxy-4-(methylthio)butanenitrile.

sotic acid.

CAS: 17773-41-0. mf: C

NOS.

Hazard: A poison by ingestion and skin contact. A

3-hydroxy-3-methylbutan-2-one.

moderate skin irritant.

COH(CH

)C(O)CH

. Colorless liquid, d 0.95

(25/25C). Combustible.

hydroxynaphthalene. See naphthol.

Use: Intermediate.

3-(6-hydroxy-2-naphthalenyl)-1,2-dimethyl

7-hydroxy-4-methylcoumarin. See ␤-me-

(2r,3s)-rel-3-pyrrolidinol ydrochloride.

thylumbelliferone.

CAS: 210828-80-1. mf: C

•ClH.

Hazard: A poison.

4-hydroxymethyl-2,6-di-tert-butylphenol.

[(CH

)

(OH)(CH

OH).

3-hydroxy-2-naphthoic acid. (␤-hydroxyna-

Properties: White, crystalline powder. Mp

phthoic acid; 3-naphthol-2-carboxylic acid; ␤-

140–141C, bp 162C (2.6 mm Hg), flash p 375F

oxynaphthoic acid).

(190.5C), vap press 0.03 mm Hg (100C), bulk d 26

CAS: 92-70-6. C

OHCOOH.

lb/ft

. No odor. Partially soluble in methanol, etha-

Properties: Yellow, rhombic leaflets. Mp

nol, and acetone; insoluble in water. Combustible.

217–219C. Soluble in alcohol and ether; insoluble in

Hazard: Toxic by ingestion.

water.

Use: Antioxidant for gasoline and other hydro-

Derivation: By treating sodium-2-naphtholate with

carbons.

carbon dioxide under pressure.

Hazard: Irritant.

hydroxymethylethylene carbonate. See

Use: Dyes and pigments.

glycerin carbonate.

␤-hydroxynaphthoic anilide. (naphthol AS;

5-hydroxymethyl-2-furaldehyde. (5-hy-

azoic coupling component 2).

droxymethyl-2-formylfuran). C

OHCONHC

Properties: Crystalline solid (needles). D 1.20, refr

Properties: Cream-colored crystals. Mp 246.0C. So-

index 1.56, UV absorption max: 283 nm, soluble in

dium salt is soluble in water.

water and common organic solvents, protect from

Derivation: Condensation of ␤-hydroxynaphthoic

light and oxygen.

acid and aniline.

Derivation: From glucose, cornstarch, sucrose, mo-

Use: Dyes.

lasses.

Use: Organic synthesis for glycols, acetals, alde-

2-hydroxy-1,4-naphthoquinone.

hydes, etc.

(OH).

Properties: Yellow to orange-yellow needles or

dl-␣-hydroxy-␥-methylmercaptobutyric

powder. Mp 192–195C (decomposes). Redox po-

acid, calcium salt. See methionine hy-

tential 0.362 volt. Soluble in cold water, benzene,

droxy analog calcium.

carbon tetrachloride, and petroleum ether.

Use: Intermediate for pharmaceuticals, henna hair

2-hydroxymethyl-5-norbornene. See 5-nor-

and wool dyes, bactericides; seed disinfectant.

bornene-2-methanol.

5-hydroxy-1,4-naphthoquinone. (juglone).

4-hydroxy-4-methylpentan-2-one. See di- CAS: 481-39-0. This compound derived from wal-

acetone alcohol. nuts is the starting point in the 16-step synthesis of

6764-HYDROXY-3-NITROBENZENE

oxytetracycline. It has also been found to be a natu-

2-hydroxyphenylmercuric chloride. (chlo-

ral herbicide with allelopathic properties. romercuriphenol).

CAS: 90-03-9. HOC

HgCl.

Properties: White to faint-pink fine crystals. Mp

4-hydroxy-3-nitrobenzenearsonic acid. (3-

152C. 0.1 Part in 100 soluble in water (25C); soluble

nitro-4-hydroxyphenylarsonic acid).

in hot water, alkali, and alcohol.

HOC

(NO

)AsO(OH)

Hazard: Skin irritant. TLV: 0.01 (Hg) mg/m

Properties: Pale-yellow crystals.

Use: Antiseptic, fungicide.

Derivation: Heating phenol with arsenic and treating

the p-hydroxyphenyl arsonate with nitric and sulfu-

ric acids.

3-hydroxy-n-phenyl-2-naphthalene-

Hazard: Toxic by ingestion.

carboxamide. See C.I. azoic coupling

component 2.

4-hydroxy-nonachlorodiphenyl ether.

CAS: 21567-21-5. mf: C

HCl

hydroxyphenylstearic acid. A derivative of

Hazard: A poison.

phenylstearic acid potentially useful as oxidation

and corrosion inhibitor.

4-hydroxynonanoic acid, ␥-lactone. See

␥-nonyl lactone.

(s)-1-(3-hydroxy-2-phosphonylmethoxy-

propyl)cytosine.

cis-12-hydroxyoctadec-9-enoic acid. See

CAS: 113852-37-2. mf: C

ricinoleic acid.

Hazard: A severe skin irritant.

12-hydroxyoleic acid. See ricinoleic acid.

1-hydroxypiperidine. C

NOH.

Properties: Soluble in water, organic solvents, aque-

15-hydroxypentadecanoic acid lactone.

ous acids, and bases.

See pentadecanolide.

Use: Intermediate, reducing agent, polymerization

inhibitor for vinyl monomers, antioxidant, metal ion

3-hydroxyphenol. See resorcinol.

reduction.

2-hydroxy-2-phenylacetophenone. See

benzoin.

11-␣-hydroxyprogesterone. C

Properties: White, crystalline powder. Mp 163, spe-

cific rotation +179 degrees. Insoluble in water; solu-

␤-p-hydroxyphenylalanine. See tyrosine.

ble in alcohol.

Derivation: From progesterone by microbiological

2-(2

′

-hydroxyphenyl)benzotriazole.

oxidation.

HOC

. An UV light absorber.

Use: A steroid intermediate, biochemical research.

Use: Plastics.

p-hydroxyphenyl benzyl ether. See p-ben-

4-hydroxyproline. (Hyp; 4-hydroxy-2-pyrroli-

zyloxyphenol.

dinecarboxylic acid). HOC

NCOOH.

4-(p-hydroxyphenyl)-2-butanone acetate.

See Cuelure.

(+−)-4-hydroxy-␣1-(((6-(4-phenylbutoxy)

hexyl)amino)methyl)-1,3-benzene-

Properties: Colorless crystals. Very soluble in wa-

dimethanol.

ter; slightly soluble in alcohol; insoluble in ether.

CAS: 89365-50-4. mf: C

Optically active. dl-hydroxyproline, mp 261–262C

Hazard: A poison by inhalation.

with decomposition.l-hydroxyproline, mp 270C

(natural). d-hydroxyproline, mp 274C.

N-(p-hydroxyphenyl)glycine. (glycine

Derivation: Hydrolysis of protein (gelatin), organic

[photographic]; photo-glycin).

synthesis.

HOC

NHCH

COOH.

Use: Biochemical research. Available commercially

Properties: White to buff crystals or powder. Mp

as l-hydroxyproline.

240C (with decomposition). Slightly soluble in wa-

ter; soluble in alkaline solutions.

3-hydroxy-1-propanesulfonic acid sultone.

Derivation: By condensation of p-aminophenol with

See propane sultone.

chloroacetic acid.

Use: Photographic developer, cellulose and nitrocel-

lulose acetate lacquers and varnishes, analytical re-

2-hydroxy-1,2,3-propanetricarboxylic acid.

agent. See citric acid.

677 8-HYDROXYQUINOLINE

hydroxy-2-propanone. (acetol; acetonyl al- ed solubility in water; soluble in common organic

cohol; acetylcarbinol; hydroxyacetone; pyruvic solvents. Combustible.

alcohol). CH

COCH

OH. Use: Monomer for acrylic resins, nonwoven fabric

binders, detergent lubricating-oil additives.

Properties: Colorless liquid. D 1.0824 at 20/20C, bp

146C, fp −17C. Soluble in water, alcohol and ether.

Combustible.

hydroxypropyl methylcellulose. (methyl-

Derivation: (1) By action of potassium acetate or

cellulose; propylene glycol ether).

potassium formate on a solution of bromo- or chlor-

Properties: White powder. Swells in water produc-

oacetone in dry methanol; (2) by bacterial fermenta-

ing clear to opalescent, viscous, colloidal solution.

tion of propylene glycol.

Insoluble in anhydrous alcohol, ether, and chloro-

Grade: Technical.

form. Combustible.

Use: Solvent for nitrocellulose.

Grade: NF, FCC.

Use: Food products (except confectionery), as thick-

␣-hydroxypropionic acid. See lactic acid.

ening agent, stabilizer, emulsifier; thickener in

paint-stripping preparations.

␣-hydroxypropionitrile. See lactonitrile.

N-␤-hydroxypropyl-o-toluidine.

␤-hydroxypropionitrile. See ethylene cya-

NHCH

CH(OH)CH

nohydrin.

Properties: Amber color. Distillation range

170–180C (20 mm Hg), d 1.035–1.045 (20/20C),

refr index 1.540–1.550 (20C).

2-hydroxypropyl acrylate. (HPA).

Use: Dye intermediate.

CAS: 999-61-1. CH

CHCOOCH

OCH

functional monomer used in manufacture of thermo-

setting acrylic resins for surface coatings.

4-hydroxy-2H-pyran-3,3,5,5(4H,6H)tetra-

Properties: A liquid. Mw 130.14, bp 77C at 5 mm

methanol. See anhydroenneaheptitol.

Hg.

Hazard: TLV: 0.5 ppm. Corrosive to skin and eyes.

2-hydroxypyridine-N-oxide. Bactericidal

Toxic by skin absorption.

agent related to aspergillic acid, made from pyri-

Use: In manufacture of thermosetting resins for sur-

dine-N-oxide.

face coatings.

1-hydroxy-2-pyridine thione. (2-pyridineth-

2-hydroxypropylamine. See isopropanola-

iol-1-oxide). C

NOH(S). Apparently exists in

mine.

equilibrium with the −SH form. Forms chelates with

iron, manganese, zinc, etc.

hydroxypropyl cellulose.

Use: Fungicide, bactericide.

CAS: 9004-64-2. A cellulose ether with hydroxy-

propyl substitution.

4-hydroxy-2-pyrrolidinecarboxylic acid.

Properties: White powder. Soluble in water, methyl

See hydroxyproline.

and ethyl alcohols, and other organic solvents. Ther-

moplastic; can be extruded and molded. Insoluble in

water >37.7C. Combustible.

8-hydroxyquinoline. (8-quinolinol; oxyquino-

Grade: FCC.

line; oxine).

Use: Emulsifier, film former, protective colloid, sta-

CAS: 148-24-3. C

NOH.

bilizer, suspending agent, thickener, food additive.

Properties: White crystals or powder; phenolic odor.

Mp 73–75C; bp 267C. Darkens when exposed to

light. Technical grade usually tan. Almost insoluble

s-(3-hydroxypropyl)-l-cysteine.

in water; soluble in alcohol, acetone, chloroform,

CAS: 13189-98-5. mf: C

benzene, and in formic, acetic, hydrochloric, and

Hazard: A reproductive hazard.

sulfuric acids, and alkalies

Grade: CP, technical.

hydroxypropylglycerin.

Hazard: Toxic by ingestion.

Properties: Pale straw-colored liquid. D 1.084 (25/

Use: Precipitating and separating metals, preparation

25C), refr index 1.459 (25C), flash p 380F (193C),

of fungicides, chelating agent, disinfectant.

pour p −23C. Soluble in water and methanol. Com-

bustible.

Use: Intermediate for alkyd resins and polyesters,

8-hydroxyquinoline benzoate.

plasticizer for cellulosics, glue, starch, etc.

CAS: 86-75-9. C

NOH:C

COOH.

Properties: Yellowish-white crystals with a saffron

hydroxypropyl methacrylate. odor. Mp 56–61C. Almost insoluble in water; solu-

OCH

OOCC(CH

):CH

. ble in alcohol and glycerol.

Properties: Clear, mobile liquid. D 1.066 (25/16C), Use: Antiseptics, fungicide, recommended against

refr index 1.446 (25C), flash p 206F (96.6C). Limit- Dutch elm disease.

6788-HYDROXYQUINOLINE

8-hydroxyquinoline sulfate. hydroxytributylstannane-4,4-

dimethyloctanoate. See tributyltin neode-

CAS: 134-31-6. (C

NO)

•H

canoate.

Properties: Pale-yellow powder; slight saffron odor;

burning taste. Melting range 167–182C. Soluble in

2-hydroxy-3,5,6-trichloropyridine.

water; slightly soluble in alcohol; insoluble in ether.

CAS: 6515-38-4. mf: C

NO.

Use: Antiseptic, antiperspirant, deodorant, fungicide.

Hazard: Moderately toxic by ingestion and skin con-

tact.

4-hydroxysalicylic acid. See ␤-resorcylic

acid.

hydroxytrimethylstannane. See trimethyltin

hydroxide.

12-hydroxystearic acid.

CAS: 106-14-9. CH

(CH

)

(CH

O)(CH

)

COOH. A

5-hydroxytryptamine. See serotonin.

straight-chain fatty acid with an −OH group at-

tached to the carbon chain, mp 79–82C. It is pro-

4-hydroxyundecanoic acid, ␥-lactone. See

duced by hydrogenation of ricinoleic acid. Combus-

␥-undecalactone.

tible.

Use: Lithium greases, chemical intermediates.

hydrozincite. (zinc bloom). Zn

(OH)

(CO

)

1,12-hydroxystearyl alcohol. (1,12-octade- natural basic carbonate of zinc found in the upper

canediol). A long-chain fatty alcohol made by re- zones of zinc deposits.

duction of 12-hydroxystearic acid by replacing the Properties: White to gray or yellowish color, dull to

−COOH group with a −CH

OH. Combustible. silky luster. Fluorescent in UV light. D 3.5–4.0,

Properties: Boiling range 315–335C, mp 69C. Mohs hardness 2.0–2.5.

Use: Chemical intermediate, synthetic fibers, organic Occurrence: Missouri, Pennsylvania, Utah, Califor-

synthesis, pharmaceuticals, surface-active agents, nia, Nevada, Europe.

plastics and resins, protective coatings. Use: An ore of zinc.

hydroxysuccinic acid. See malic acid.

“Hydrozon” [Carus]. TM for a system based

on ozone.

2-hydroxy-1,2,3,3-tetrahydro-3h-pyrano Use: To treat drinking water that incorporates oxida-

(3,2-f)quinoline-8(7h)-one. tion, coagulation, flocculation, filtration, and disin-

CAS: 128202-33-5. mf: C

. fection.

Hazard: Moderately toxic by ingestion.

hydyne. Mixture of 60% (by weight) of uns-di-

4-hydroxy-3-(1,2,3,4-tetrahydro-3-(4-(4-

methylhydrazine and 50% diethylenetriamine.

(trifluoromethyl)phenoxy) phenyl)-1-

Use: High-energy fuel.

naphthalenyl)2h-1-benzopyran-2-one.

CAS: 90035-14-6. mf: C

“Hyform” [Cytec]. TM for water emulsions of

Hazard: A poison by ingestion.

pure paraffin wax, microcrystalline wax, or a modi-

Use: Agricultural chemical.

fication of one of these waxes.

Use: Binders for pressed ceramic pieces, lubricants

4-hydroxy-3-(1,2,3,4-tetrahydro-3-(4-

for die or mold release, and plasticizers during mold

(trifluoromethyl)phenyl)-1-

forming.

naphthalenyl)2h-benzopyran-2-one.

CAS: 90034-99-4. mf: C

hygromycin.

Hazard: A poison by ingestion.

CAS: 31282-04-9. C

Use: Agricultural chemical.

Properties: White powder. Weakly acidic. Freely

soluble in water and alcohol. Produced by Strepto-

hydroxythiospasmin.

myces hygroscopicus.

CAS: 3569-58-2. mf: C

S•I.

Use: Medicine (broad-spectrum antibiotic).

Hazard: A poison by ingestion.

hygroscopic. Descriptive of a substance that has

hydroxytoluene. See cresol.

the property of adsorbing moisture from the air, such

as silica gel, calcium chloride or zinc chloride. The

␣-hydroxytoluene. See benzyl alcohol.

water-vapor molecules are held by the molecules of

the agent, which is called a desiccant when used

hydroxytoluic acid. See cresotic acid.

primarily for this purpose. Paper and cotton fabrics

are hygroscopic, normally containing 5–8% water

1-hydroxytriacontane. See 1-triacontanol.

after standing in an atmosphere of normal humidity;

they are usually kept in constant-humidity rooms

(hydroxy)tributylstannane. See tributyltin before use. Many dry chemicals are hygroscopic and

hydroxide. should be kept in well-stoppered bottles or tightly

679 HYPOPHOSPHORIC ACID

closed containers.

hypnone. See acetophenone.

See deliquescent.

hypo-. (1) A prefix used in chemical terminology

“Hylene” [Du Pont]. TM for a series of organ-

to indicate a compound (usually an acid) in its low-

ic isocyanates. “M-50”, 50% methylenebis(4-phe-

est oxidation state or containing the lowest propor-

nyl isocyanate) (C

NCO)

, in monochloroben-

tion of oxygen in a series of compounds, e.g., nitric

zene. Used in adhesives.

acid (HNO

), nitrous acid (HNO

), hyponitrous acid

See diphenylmethane diisocyanate. “MP” Bisphenol

). (2) Common term for a photographic

adduct of methylenebis(4-phenyl)isocyanate. Used

chemical.

as bonding agent for adhering “Dacron” fiber to

See sodium thiosulfate.

rubber compositions. “T” Toluene-2,4-diisocya-

nate, used for urethane products. “TM” 80% tolu-

hypoallergenic. A term used in the cosmetics

ene-2,4-diisocyanate and 20% toluene-2,6-diisoc-

industry and defined by the FDA as describing a

yanate. “TM-65” 65% 2,4-compound and 35% 2,6-

cosmetic product that is less likely to cause adverse

compound.

allergenic reactions than are competing products.

Claims of hypoallergenicity must be substantiated

Hyp. Abbreviation for hydroxyproline.

by specific dermatological tests made by the manu-

facturer of the product.

“Hypalon” [Du Pont]. TM for chlorosulfo-

nated polyethylene, a synthetic rubber.

hypobromous acid. HBrO. An unstable com-

Properties: White chips. D 1.10–1.28. Resistant to

pound resulting from hydrolysis of bromine chlo-

ozone as well as the weather, oil, solvents, chemi-

ride.

cals, and abrasion.

Use: Bactericide and wastewater disinfectant.

Use: Insulation for wire and cable, shoe soles and

heels, automotive components, building products,

hypochlorite solution. An aqueous solution of

coatings, flexible tubes and hoses, seals, gaskets,

a metallic salt of hypochlorous acid. Strong oxidiz-

diaphragms. “Hypalon” 45 can accept large

ing agent.

amounts of filler and is used as a binder for pow-

Hazard: Irritant to skin and eyes.

dered metal to produce magnetic gaskets for doors

Use: Bleaching of textiles, antiseptic agent.

and sheet goods for x-ray barriers.

hypochlorous acid.

hyperchromic effect. The large increase in

CAS: 7790-92-3. HOCl.

light absorption at 260 nm occurring as a double-

Properties: Greenish-yellow aqueous solution.

helical DNA is melted.

Highly unstable, weak acid. Decomposes to hydro-

gen chloride and oxygen. Can exist only in dilute

hyperfine structure. Structure of spectral line

solutions.

making each ordinary line a multiplet.

Derivation: Water solution of chloride of lime

(bleaching powder).

hyperglycemic-glycogenolytic factor. See

Hazard: Irritant to skin and eyes.

glucagon.

Use: Textile and fiber bleaching, water purification,

antiseptic.

See hypochlorite solution; calcium hypochlorite; so-

hypergolic fuel. A liquid rocket fuel or propel-

dium hypochlorite.

lant which consists of combinations of fuels and

oxidizers which ignite spontaneously on contact.

“Hypol” [Grace]. TM for a family of hydro-

philic polyurethane polymers derived from toluene

hyperon. Short-lived nuclear particle with mass

diisocyanate (TDI). Foams with addition of water.

greater than that of the neutron.

Good fire retardancy, high additive loading.

Use: Consumer, medical, biomedical, and industrial

hypersorption. Process in which activated car-

applications.

bon selectively adsorbs the less-volatile compo-

nents from a gaseous mix, while the more-volatile

␣-hypophamine. See oxytocin.

components pass on unaffected. Particularly appli-

cable to separations of low-boiling mixtures such as

hydrogen and methane, ethane from natural gas,

␤-hypophamine. See vasopressin.

ethylene from refinery gas, etc.

hypophosphoric acid. H

hypertensin. See angiotensin.

Properties: Platelike crystals. Commercially avail-

able as water solution. Readily forms hydrates. Mp

hypertonic. (1) Possessing greater osmotic pres- 70C, mp (hydrated) 55C, the solution decomposes

sure than a standard; (2) Having a higher than iso- when concentrated.

tonic concentration. Use: Baking powder (sodium salt).

680HYPOPHOSPHOROUS ACID

hypophosphorous acid. field that it did when the field was increasing, but

CAS: 6303-21-5. H

. lags behind the decreasing field. Hysteresis is analo-

Properties: Colorless, oily liquid or deliquescent gous to mechanical inertia and the energy lost is

crystals; sour odor. D 1.439, mp 26.5C. Soluble in analogous to that lost in mechanical friction. It

water. A strong monobasic acid and reducing agent, presents a major problem in the design of electrical

sold in solution. machines with iron cores such as transformers and

Derivation: Heating concentrated baryta water with rotating armatures. In instruments designed for very

white phosphorus and decomposing the barium hy- high frequencies, the retardation and losses are so

pophosphite with sulfuric acid, filtering the liquid, great as to render iron cores useless. The stress-

and concentrating under reduced pressure. strain curves of vulcanized rubber also display hys-

Grade: Technical, NF (30–32% solution, d 1.13), teresis, in that strain (elongation, crystallization)

50% purified. persists when the deforming stress is removed, thus

Hazard: Fire and explosion risk in contact with oxi- producing a hysteresis loop instead of a reversible

dizing agents. pathway of the curves. This loop indicates a loss of

Use: Preparation of hypophosphites, electroplating resilient energy (Norman E. Gilbert).

baths. Note: The simple diagram shown below is a general-

ized representation of a hysteresis loop.

hypoxanthine.

CAS: 68-94-0. C

O. An intermediate in the

metabolism of animal purines, also widely distribut-

ed in the vegetable kingdom.

Properties: White to cream powder. Decomposes at

150C. Almost insoluble in cold water; slightly solu-

ble in boiling water; soluble in dilute acids and

alkalies.

Derivation: Deamination of adenine, reduction of

uric acid.

Use: Biochemical research.

hypoxanthine riboside. See inosine.

“Hystrene” [Crompton & Knowles]. (be-

hypoxanthine riboside-5-phosphoric acid.

henic acid). TM for fatty acids.

See inosinic acid.

Properties: Light colors and stable.

Grade: Food grade products.

hysteresis. (Derived from the Greek word

Use: Waxes, textiles, pharmaceuticals, emulsifiers,

meaning “to lag behind.”) A retardation of the

and personal care products, lubricants, esters, chem-

effect, as if from viscosity, when the forces acting

ical synthesis, and specialties.

upon the body are changing. A common illustration

is the retentivity of induction in ferromagnetic mate-

rials such as iron and its alloys when the magnetiz-

ing force is changed. When such a substance is

“Hytrel” [Du Pont]. TM for a series of polyes-

placed in a magnetizing coil and the magnetizing ter elastomers.

field is gradually increased to a given value, and then Use: In sports equipment, automobile parts, hoses,

decreased, the magnetic induction, in decreasing tubes, belts, couplings, gears, seals, and electronic

does not follow the same relation to the magnetizing parts.