L. (l). Abbreviation for liter. cifically, the term refers to experimental or small-

batch conditions as opposed to large-scale

production.

L-. (L-). Prefix indicating the left-handed enantio-

mer of an optical isomer. Often displayed as a small

laboratory machinery. Small-scale working

capital letters.

models of basic types of equipment used for experi-

See

mental purposes in the laboratories of many chemi-

cal process industries. Commercially available are

l-. (l-). Prefix indicating that a compound is levo-

such items as calenders, mills of various kinds, mix-

rotatory. A minus sign (−) is now preferred.

ers, autoclaves, extruders, electric furnaces, distilla-

See d-.

tion columns, etc. A machine as complex as a four-

drinier can be duplicated in laboratory size (about 10

La. Symbol for lanthanum.

ft by 18 in.).

label. (1) A warning notice required by DOT or

laccase. An enzyme that oxidizes phenols or o-

IATA to be placed on the shipping container of a

and p-quinones.

hazardous material transported by air, highway, rail,

Occurrence: It occurs in the latex of the lac tree, in

or water. Names of some labels are as follows:

potatoes, sugar beets, apples, cabbages, and other

Corrosive Irritant

plants.

Dangerous when Wet Nonflammable Gas

Explosive Organic Peroxide

lac dye. (CI Natural Red 25; lacchaid acid).

Flammable Gas Oxidizer

CAS: 60687-93-6. A brilliant red dye obtained by

Flammable Liquid Poison

maceration of crude lac.

Flammable Solid Radioactive

See shellac.

(2) A notice required to appear on a food product

indicating its composition and nutritional value

lachrymator.

(lacrimator). A material (gas) that

(RDA), or on a pharmaceutical or household prod-

is strongly irritant to the eyes; tear gas.

uct stating its hazardous properties. (3) A radioac-

tive isotope or fluorescent dye added to a chemical

L acid. (1-naphthol-5-sulfonic acid).

compound to trace its course and behavior through a

(OH)SO

series of reactions, usually in living organisms. This

Properties: White solid. Soluble in water.

technique has also been used to measure frictional

Derivation: From naphthalene-1,5-disulfonic acid

wear of moving parts of automotive engines.

by fusion with sodium hydroxide.

See tracer; tagged compound.

Use: Azo dye intermediate.

labeled compound. Refers to material contain-

lacmoid. (resorcinol blue).

ing radioactive atoms.

(HO)

N[C

(OH)

]

Use: As a tracer in chemical reactions and medical

Properties: Lustrous, dark-violet, crystalline scales.

diagnosis.

Soluble in alcohol, ether, acetone, phenol, and gla-

cial acetic acid; slightly soluble in water; pH

labeling. (labelling). Replacement of a stable

4.4–6.2.

atom in a compound with a radioisotope of the same

Derivation: From resorcinol by treatment with sodi-

element. This facilitates tracing the path of the

um nitrite.

chemical through a biological or mechanical system

Use: Indicator in analytical chemistry (more sensi-

by detection of the radiation. Triated compounds

tive than litmus).

have a hydrogen atom replaced by a tritium atom.

lacquer. A protective or decorative coating that

labile. Descriptive of a substance that is inactivat-

dries primarily by evaporation of solvent, rather

ed by high temperature or radiation, e.g., a heat-

than by oxidation or polymerization. Lacquers were

labile vitamin, unstable.

originally comprised of high-viscosity nitrocellu-

lose, a plasticizer (dibutyl phthalate or blown castor

laboratory conditions. An ideal set of condi- oil), and a solvent. Later, low-viscosity nitrocellu-

tions in which all variant factors except the one lose became available; this was frequently modified

under test can be held constant, as for example, with resins, such as ester gum or rosin. The solvents

rooms provided with constant temperature and hu- used are ethanol, toluene, xylene, and butyl acetate.

midity control, clean rooms, and the like. Less spe- Together with nitrocellulose, alkyd resins are used

735

736LACTALBUMIN

to improve durability. The nitrocellulose used for soon as formed with calcium or zinc carbonate. The

solution of lactates is concentrated and decomposed

lacquers has a nitrogen content of 11–13.5% and is

with sulfuric acid. (2) Synthetically by hydrolysis of

available in a wide range of viscosities, compatibili-

lactonitrile.

ties, and solvencies. Chief uses of nitrocellulose-

Grade: Technical 22% and 44%, food 50–80%, plas-

alkyd lacquers are for coatings for metal, paper

tic 50–80%, USP (85–90%), CP, FCC.

products, textiles, plastics, furniture, and nail polish.

Use: Cultured dairy products, as acidulant, chemicals

Various types of modified cellulose are also used as

(salts, plasticizers, adhesives, pharmaceuticals),

lacquer bases, combined with resins, and plasticiz-

mordant in dyeing wool, general-purpose food addi-

ers. Many noncellulosic materials such as vinyl and

tive, manufacture of lactates.

acrylic resins are also used, as are bitumens, with or

without drying oils, resins, etc.

See nitrocellulose.

lactic acid dehydrogenase. An enzyme

Hazard: Flammable, dangerous fire and explosion

found in animal tissues and yeast which takes part in

risk.

controlling carbohydrate metabolism in the cell.

Use: Biochemical research.

lactalbumin. See albumin, milk.

lactogenic hormone. See luteotropin.

lactam. A cyclic amide produced from amino

acids by the removal of one molecule of water. An

lactoglobulin. A protein found in milk. It com-

example is caprolactam, CH

(CH

)

CONH, derived

prises from 7 to 12% of the skim milk protein and is

from epsilon-aminocaproic acid, NH

(CH

)

COOH.

closely associated with casein.

lactase. An enzyme present in intestinal juices

lactone. An inner ester of a carboxylic acid

and mucosa that catalyzes the production of glucose

formed by intramolecular reaction of hydroxylated

and galactose from lactose.

or halogenated carboxylic acids with elimination of

Use: Biochemical research.

water. The resulting ring compound contains the

group −CO•O−.

lactase enzyme preparations from

Derivation: In nature as odor-bearing components of

Kluyveromyces lactis.

various plant products; also made synthetically.

Properties: Derived from Kluyveromyces lactis.

See butyrolactone; propiolactone.

Use: Food additive.

lactonitrile. (␣-hydroxypropionitrile; acetalde-

lactate. An ester or salt of lactic acid, for example,

hyde cyanohydrin).

ethyl lactate.

CAS: 78-97-7. CH

OCN.

Properties: Straw-colored liquid. Acid to methyl

red, fp −40C, bp 182–184C (slight decomposition),

lactated mono-diglycerides.

d 0.9919 (18.4C), refr index 1.4058 (18.4C), flash p

Properties: Soft to hard waxy solid. Dispersible in

170F (76.6C). Soluble in water and alcohol; insolu-

hot water; moderately sol in hot isopropanol, xylene,

ble in petroleum ether and carbon disulfide. Com-

cottonseed oil.

bustible.

Use: Food additive.

Derivation: Acetaldehyde and hydrocyanic acid.

Grade: Technical, 95–97% purity.

lactic acid. (␣-hydroxypropionic acid; milk

Hazard: Toxic by inhalation, ingestion, and skin

acid).

absorption; evolves hydrocyanic acid in presence of

CAS: 50-21-5. CH

OCOOH.

alkali.

Use: Solvent, intermediate in production of ethyl

lactate and lactic acid.

lactose. (milk sugar; saccharum lactis).

CAS: 63-42-3. C

•H

Properties: Colorless or yellowish syrupy liquid;

odorless; hygroscopic. Bp 122C (15 mm Hg), mp

18C, d 1.2. Miscible with water, alcohol, glycerol,

and furfural; insoluble in chloroform, petroleum

ether, carbon disulfide. Cannot be distilled at atmo-

spheric pressure without decomposition; when con-

centrated above 50% it is partially converted to

lactic anhydride. It has one asymmetric carbon and

two enantiomorphic isomers. The commercial form

is a racemic mixture.

Derivation: (1) By fermenting starch, milk whey, Properties: White, hard, crystalline mass or white

molasses, potatoes, etc. and neutralizing the acid as powder; sweet taste; odorless; stable in air. D 1.525,

737 “LAMITEX”

mp decomposes at 203.5C. Soluble in water; insolu-

lake. An organic pigment produced by the interac-

ble in ether and chloroform; very slightly soluble in tion of an oil-soluble organic dye, a precipitant, and

alcohol. an absorptive inorganic substrate. Insoluble in wa-

Derivation: From whey, by concentration and crys- ter; poor lightfastness makes lakes unsuitable for use

tallization. Cows’ milk contains about 5% lactose. in exterior paints.

Grade: Crude, fermentation, spray-dried, edible, Use: Printing inks, wallpaper inks, metal decorative

USP.

coatings, coated fabrics, rubber, plastics, food colo-

Use: Pharmacy; infant foods; bacteriology; baking

rants.

and confectionery; margarine and butter manufac-

See toner; alizarin; madder lake.

ture; manufacture of penicillin, yeast, edible protein,

and riboflavin; culture media; adsorbent in chroma-

Lake Red carbon. Red pigments made by

tography.

coupling 2-chloro-5-aminotoluene-4-sulfonic acid

with ␤-naphthol and forming various metal salts.

Properties: Good resistance to bleeding, reasonable

lactylic esters of fatty acids.

light resistance, good transparency. Produces inks

Properties: Hard, waxy solid to liquid. Dispersible in

with good flow.

hot water; sol in org solvs, vegetable oil.

Grade: Resinated and nonresinated.

Use: Food additive.

Use: General purpose colors for letterpress, gravure,

flexographic, moisture-set, heat-set inks, especially

lac wax. A wax obtained from lac consisting of

for offset printing inks.

myricyl and ceryl alcohols, free and combined with

various fatty acids. Combustible.

“Lamchem PE-130” [Lambent]. TM for a

See shellac.

phosphate ester.

Use: As a PE additive lubricant and metal working

LAD. Abbreviation for lithium aluminum deu-

fluid.

teride.

lambda-cyhalothrin.

ladder polymer. An ordered molecular net-

CAS: 91465-08-6. mf: C

ClF

work of double-stranded chains connected by hy-

Hazard: A poison by ingestion. Moderately toxic by

drogen or chemical bonds located at regular inter-

skin contact and inhalation.

vals along the chains. Many complex proteins,

Use: Agricultural chemical.

including DNA, are of this nature.

lamb shift. A small energy difference between

Ladenburg rearrangement. Thermal rear-

two levels (

1/2

and

1/2

) in the hydrogen spectrum.

rangement of an alkyl- or benzylpyridinium halide

The shift results from the quantum interaction be-

to an alkyl- or benzylpyridine.

tween the electromagnetic radiation and the atomic

electron. It was first explained by Willis Eugene

ladle. A refractory-lined pot or vessel equipped a

Lamb.

spout and with lugs for handling by a crane used to

transport molten metal from the furnace to ingot

lamepon. An acetylated peptide used as a sur-

molds, into which the metal is poured from the ladle.

face-active agent.

lagging strand. The DNA strand that, during

laminate. A composite made of any one of sever-

replication, must be synthesized in the direction

al types of thermosetting plastic (phenolic, polyes-

opposite to that in which the replication fork moves.

ter, epoxy, or silicone) bonded to paper, cloth, asbes-

It is synthesized via a series of fragments called

tos, wood, or glass fiber. High tensile and dielectric

Okazaki fragments.

strength and low moisture absorption are character-

istic of these products. Available as sheet, rod, or

lagoon. A scientifically constructed pond 3–5 ft

tubing in mechanical, electrical, and general-pur-

deep in which sewage and other organic wastes are

pose grades (National Electrical Manufacturers As-

decomposed by the action of algae, sunlight, and

sociation). Plywood is composed of a veneer with

oxygen, thus restoring water to a purity equal to that

grain oriented at a 90-degree angle on successive

obtained with other types of treatment. These so-

layers and bonded with a thermosetting adhesive of

called oxidation ponds are often used following acti-

the urea or phenol-formaldehyde type to give a high

vated sludge treatment. The waste may be retained

strength, dimensionally stable, weather-resistant

in the lagoon for as long as 30 days and is then

construction material. It can be made nonflammable

chlorinated and passed through a trickle filter.

by treatment with salt solution. Polyvinyl butyral

sheet is used in safety glass.

LAH. Abbreviation for lithium aluminum hy-

See reinforced plastic.

dride.

“Lamitex” [Fudow]. TM for laminated fiber

laid (papermaking). See dandy roll. material.

738LAMPBLACK

lampblack. A black or gray pigment made by lanolin.

Properties: (Hydrous): Yellowish to gray semisolid

burning low-grade heavy oils or similar carbona-

containing 25–30% water. Slight odor. (Anhy-

ceous materials with insufficient air and in a closed

drous): Brownish-yellow semisolid containing no

system such that the soot can be collected in settling

more than 0.25% water but can be mixed with about

chambers.

twice its weight of water without separation.

Properties: Markedly different from carbon black.

Derivation: Purification of degras, a crude grease

Strongly hydrophobic. Nonflammable.

obtained by solvent-treatment of wool. Contains

Use: Black pigment for cements, ceramic ware, mor-

cholesterol esters of higher fatty acids. Hydrogenat-

tar, inks, linoleum, surface coatings, crayons, pol-

ed, ethoxylated, and acetylated derivatives are avail-

ishes, carbon paper, soap, etc.; ingredient of insulat-

able.

ing compositions, liquid-air explosives, matches,

Grade: Technical, cosmetic, USP.

fertilizer, furnace lutes, lubricating compositions,

Use: Ointments, leather finishing, soaps, face

carbon brushes; reagent in cementation of steel.

creams, facial tissues, hair-set, and suntan prepara-

See carbon black.

tions.

See degras.

“Lanaset” [Cytec]. TM for wool dyes with

optimal fastness and minimal fiber damage.

lanolin, anhydrous.

land. (1) The portion of a mold that provides the

Properties: Yellow-white semisolid. Insol in water;

separation or cutoff of the flash from the molded

sol in chloroform, ether.

article. (2) The surface along the top of the flights or

Use: Food additive.

ribs of the screw of an extruder. (3) In an extrusion

die, the surface parallel to the flow of material.

lanosterol. (isocholesterol). C

O. An unsatu-

rated sterol closely related to cholesterol.

“Lanette O” [Henkel]. (cetearyl alcohol)

Properties: Optically active crystals. Mp 139–140C.

TM for viscosity builder.

Use: For lotions, creams, and other cosmetic emul-

sions.

“Lanfrax” [Henkel]. TM for lanolin wax

emulsifier, stabilizer, emollient, crystallization in-

hibitor and film former.

Properties: Waxy solid.

Use: In creams lotions, make-up, lip products, and

suntan preparations.

langbeinite. K

(SO

)

. A natural sulfate of

lanthana. See lanthanum oxide.

potassium and magnesium found in salt deposits.

Properties: Colorless to yellowish, reddish greenish;

lanthanide series. (lanthanoid series). The

luster vitreous. Mohs hardness 3.5–4, d 2.83.

rare earth series of elements, atomic numbers 58

Occurrence: New Mexico, Germany, India.

through 71.

Use: Source of potash.

See rare earth.

Langmuir, I. (1881–1957). An American phys-

ical chemist who was awarded the Nobel Prize in

lanthanum.

1932 for his fundamental research in surface chem-

CAS: 7439-91-0. La. Metallic element of atomic

istry, especially monomolecular films. This led to

number 57, group IIIB of the periodic table, a rare

development of modern knowledge of emulsifica-

earth of the cerium group, aw 138.9055, valence

tion and detergency. Langmuir also investigated

two stable isotopes.

electrical discharges in gases and did pioneer work

Properties: White, malleable ductile metal. Oxidizes

on cloud-seeding techniques.

rapidly in air. D 6.18–6.19, mp 920C, bp 3454C.

Corrodes in moist air. Soluble in acids; decomposes

“Lannate” [Du Pont]. TM for methomyl in-

water to lanthanum hydroxide and hydrogen. Super-

secticides.

conducting at approximately 6K.

See methomyl.

Derivation: By cracking of monazite or bastnasite

ores with concentrated sulfuric acid and subsequent

“Lanogene” [Dow]. TM for liquid lanolin con- separation.

sisting of low melting point esters. A crystal-clear, Available forms: Ingots, rods, 20-mil sheets, pow-

amber, viscous liquid; anhydrous. Soluble in miner- dered, 99.9% pure.

al and vegetable oils. Hazard: Ignites spontaneously in powdered form.

Use: Nonionic with out emulsifier; pigment disper- May delay blood clotting and cause liver injury upon

sant; plasticizer; emollient. ingestion.

739 LARD OIL

Use: Lanthanum salts, electronic devices, pyrophoric

lanthanum oxalate. La

)

•9H

alloys, rocket propellants, reducing agent catalyst Properties: White powder. Insoluble in water; solu-

for conversion of nitrogen oxides to nitrogen in ble in acids.

Grade: Purities to 99.9+%.

exhaust gases (usually in combination with cobalt,

lead, or other metals), phosphors in x-ray screens.

lanthanum oxide. (lanthana; lanthanum tri-

See rare-earth metal.

oxide; lanthanum sesquioxide). La

Properties: White or buff amorphous powder. D

lanthanum acetate. La(C

)

•xH

6.51 (15C), mp 2315C, bp 4200C. Soluble in acids;

Properties: White powder. Soluble in water and

insoluble in water.

acids.

Derivation: Ignition of hydroxide or oxyacid (oxa-

Grade: Purities up to 99.9+%.

late, sulfate nitrate, etc.), direct combustion of free

metal (burns with brilliant, white light).

lanthanum ammonium nitrate.

Grade: Purities to 99.9+%.

Properties: Colorless crystals.sOluble in water.

Use: Calcium lights, optical glass, technical ceram-

Grade: Purities to 99.9+%.

ics, cores for carbon-arc electrodes, fluorescent

Hazard: Oxidizer; explosion and fire risk.

phosphors, refractories.

lanthanum antimonide. LaSb. A binary semi-

lanthanum phosphide. LaP. Made in high pu-

conductor.

rity for use as binary semiconductor.

lanthanum arsenide. LaAs. Made in high pu-

lanthanum sesquioxide. See lanthanum

rity for use as a binary semiconductor.

oxide.

Hazard: Highly toxic.

lanthanum sulfate. La

(SO

)

•9H

lanthanum carbonate. La

(CO

)

•8H

Properties: White crystals. D 2.821, refr index 1.564

Properties: White powder. D 2.6. Insoluble in water;

(20C). Insoluble in alcohol; slightly soluble in wa-

soluble in acids.

ter, acids.

Grade: Up to 99.9+% lanthanum salts.

Derivation: By dissolving hydroxide, carbonate, or

oxide in dilute sulfuric acid.

lanthanum chloranilate.

Grade: Purities to 99.9+%.

(O:C

:O)

•xH

Use: The sulfates of the rare-earth elements are often

Use: Reagent for fluoride determination.

used for atomic weight determination of the ele-

ment.

lanthanum chloride.

CAS: 10099-58-8. LaCl

•7H

lanthanum trioxide. See lanthanum oxide.

Properties: White crystals, transparent, hygroscop-

ic. Mp (hydrate) 91C (decomposes); (anhydrous) d

lanthionine. S(CH

CHNH

COOH)

. A nones-

3.842 (25C), mp 87.C; soluble in alcohol, water,

sential amino acid first obtained from deaminated

acids.

wool.

Derivation: Treatment of lanthanum carbonates or

oxides with hydrochloric acid in an atmosphere of

“Lantrol” [Henkel]. TM for lanolin oil emol-

dry hydrogen chloride.

lient and moisturizer.

Grade: Purities to 99.9+%, single crystals available.

Properties: Liquid.

Use: Anhydrous trichloride of rare-earth metal is

Use: In make-up as a pigment dispersant and cream,

often used to prepare the metal.

lotions, hair care products, bath oils, and medicinal

preparations.

lanthanum fluoride. LaF

Properties: White powder. Insoluble in water, acids.

lard. Purified internal fat of the hog.

Grade: Purities up to 99.9+%, single crystals avail-

Properties: Soft, white, unctuous mass; faint odor;

able.

bland taste. Mp 36–42C. High in saturated fats.

Hazard: Toxic by ingestion. TLV: 2.5 mg(F)/m

Soluble in ether, chloroform, light petroleum hydro-

Use: Phosphor lamp coating (gallium arsenide solid-

carbons, carbon disulfide; insoluble in water. Com-

state lamp), carbon arc electrodes, lasers.

bustible.

Chief constituents: Stearin, palmitin, olein.

Use: Cooking, pharmacy (ointments, cerates), per-

lanthanum nitrate.

fumery (pomades), source of lard oil.

CAS: 10099-59-9. La(NO

)

•6H

Properties: White crystals, hygroscopic. Bp 126C,

mp 40C. Soluble in alcohol, water, acids.

lard oil.

Grade: Purities to 99.9+%. Properties: Colorless or yellowish liquid; peculiar

Hazard: Explosion and fire risk. odor; bland taste. Mp −2C, refr index 1.470 (20C), d

Use: Antiseptic, gas mantles. 0.915, saponification value 195–196, iodine value

740LARD (UNHYDROGENATED)

56–74, subject to spontaneous heating, flash p 420F

laser-induced nuclear polarization. A

(215C), autoign temp 883F (472C). Soluble in ben-

technique for making the spin vectors of an assem-

zene, ether, chloroform, and carbon disulfide;

bly of nuclei point preferentially in one direction by

slightly soluble in alcohol. Combustible.

means of an optical pumping process using either

Chief constituents: Olein with a small percentage of

circularly or linearly polarized laser light.

the glycerides of solid fatty acids.

Derivation: By cold-pressing lard.

laser spectroscopy. A branch of spectroscopy

Grade: Prime winter edible, prime winter inedible,

in which a laser is used as an intense monochromatic

antibiotic, off prime, extra #1, #1, #2.

light source. In particular it includes saturation spec-

Use: Lubricant, metal cutting compounds, oiling

troscopy as well as the application of laser sources to

wool, soap manufacture, antibiotic fermentation.

Raman spectroscopy and other techniques.

See spectroscopy.

lard (unhydrogenated).

LATB. See lithium aluminum tri-tert-butox-

Properties: Whitish fat rendered from pork fat. Mp:

yhydride.

42°

Use: Food additive.

latent heat. The quantity of energy in calories

per gram absorbed or given off as a substance under-

larva. Among invertebrates, an immature stage in

goes a change of state, that is, as it changes from

the life cycle which usually is much smaller than,

liquid to solid (freezes), from solid to liquid (melts),

and morphologically different from, the adult. In

from liquid to vapor (boils), or from vapor to liquid

insects with metamorphosis, the larva must become

(condenses). No change in temperature occurs. Wa-

a pupa before reaching adulthood.

ter has unusually high latent heat values; the latent

heat of fusion (melting) of ice is 80 cal/g and the

larvicide. A chemical agent that kills the eggs of

latent heat of condensation of steam (latent heat of

insects. Examples are p-dichlorobenzene, chlorop-

vaporization of water) is 540 cal/g. The considerable

icrin, and copper acetoarsenite.

energy delivered by steam condensation is utilized

for power generation and for heating a variety of

LAS. See alkyl sulfonate, linear.

chemical plant equipment (dryers, evaporators, re-

actors, and distillation columns).

See evaporation; heat.

laser. A device that produces a beam of coherent

or monochromatic light as a result of photon-stimu-

latent solvent. See solvent, latent.

lated emission. Such beams have extremely high

energy, because they consist of a single wavelength

laterite. A low-grade ore similar to bauxite, but

and frequency. Laser is an acronym for light ampli-

containing only half as much aluminum oxide. Pos-

fication by stimulated emission of radiation. Materi-

sible substitute for bauxite.

als capable of producing this effect are certain high-

purity crystals (ruby, yttrium garnet, and metallic

tungstates or molybdates doped with rare-earth

latex. A white, tacky, aqueous suspension of a

ions); semiconductors such as gallium arsenide, hydrocarbon polymer occurring naturally in some

neodymium-doped glass; various gases, including species of trees, shrubs, or plants, or made syntheti-

carbon dioxide, helium, argon, and neon; and plas- cally. The most important natural latex is that of the

mas. A chemical laser is one in which the excitation tropical tree Hevea braziliensis, which was the only

energy is furnished by a chemical reaction, e.g., H + source of rubber up to 1945. It is composed of

→ HCl (active) + Cl; or combustion of carbon globules of rubber hydrocarbon coated with protein;

monoxide to form excited carbon dioxide. the particles are of irregular shape, varying from 0.5

Hazard: Laser radiation can irreparably damage the to 3 microns in diameter; the suspension is stabilized

eyes. Proper shielding is essential at all times. by electric charges. The composition is about 60%

Use: Laser beams are used in industry for cutting water, 35% hydrocarbon, 2% protein, and low per-

diamonds that are used for wire-drawing dies, and in centages of sugars and inorganic salts. For commer-

flash photolysis, spectroscopy, and photography. cial purposes, rubber latex can be concentrated by

They also have developing applications in medicine evaporation or centrifugation. Ammonia is added as

and surgery. They are being used for controlled a preservative. Coagulation is induced by addition

fusion reactions, for biomedical investigations, for of acetic or formic acid. A vulcanized form is avail-

organic chemical research, for sophisticated analyti- able. Natural latex is used in the manufacture of thin

cal techniques, and in three-dimensional photogra- articles (surgeons’ gloves and other medical equip-

phy (holography). It is possible to increase the abun- ment), as an adhesive, in foamed products, and for

dance of certain isotopes of such elements as coating various products such as tire cord. Conver-

uranium, chlorine, and boron by use of laser irradia- sion of latex to gasoline via zeolite catalysts has

tion. Research on uranium enrichment by this meth- been reported. Other sources of rubber-containing

od has been under way for several years. latex are guayule, a shrub grown in Mexico and the

See fusion (2); enrichment; holography. southwestern U.S., and several types of dandelions

741

-LAUROYL

and related species. The botanical function of latex

in the plant is unknown. Synthetic latexes are made

by emulsion polymerization techniques from sty-

rene-butadiene copolymer, acrylate resins, polyvi-

nyl acetate, and similar materials. Their particle size

is much smaller than in natural latex, ranging from

0.05 to 0.15 micron; thus, they are truly colloidal

suspensions. Their chief use is as a binder in exterior

Properties: White or pink needles, gives greenish

and interior paints, replacing drying oils; they are

fluorescence in dilute aqueous solution.

also used for foams and coatings.

Derivation: From naphthalene-␣-sulfonic acid by

See guayule; gutta percha; electrophoresis; paint;

nitration, reduction with iron, and separation from

emulsion; “Vultex.”

the 1-naphthylamine-8-sulfonic acid also formed.

Use: Azo dye intermediae.

latex paint. See paint; emulsion.

Laurent’s ␣-acid. (1-nitronaphthalene-5-sul-

fonic acid). C

(NO)

(SO

H).

“Latron AG-98” [Rohm & Haas]. TM for

Properties: Pale yellow needles. Soluble in water,

alkylaryl polyoxyethylene glycols.

alcohol, and ether. Combustible.

Use: As a spray adjuvant for agricultural pesticides.

Derivation: By sulfonating nitronaphthalene with a

mixture of chlorohydrin and sulfuric acid.

Use: Azo dye intermediate.

lattice. (1) The structural arrangement of atoms in

a crystal. Accurate information is obtained by X

rays, which are diffracted by the lattice at various

“Laurex” [Uniroyal]. TM for the zinc salts of a

angles. As the atoms are from 1.5 to 3 A

apart in

mixture of fatty acids in which lauric acid predomi-

most crystals, the lattice acts as a diffraction grating.

nates.

See crystals; dislocation.

Properties: Yellowish-white granulated waxy pow-

(2) The array of nuclear fuel elements and moderator

der. D 1.15, mp 95–105C. Soluble in benzene; insol-

in a nuclear reactor.

uble in acetone, gasoline, ethylene dichloride, and

water. Combustible.

Use: Accelerator, activator, and plasticizer for

“Latyl” [Du Pont]. TM for a group of disperse

rubber.

dyes developed particularly for coloration of “Da-

cron” polyester fiber, on which they have exception-

lauric acid. (dodecanoic acid).

ally good light- and wetfastness properties.

CAS: 143-07-7. CH

(CH

)

COOH. A fatty acid oc-

curring in many vegetable fats as the glyceride,

laudanidine. (l-laudanine; tritopine).

especially in coconut oil and laurel oil. Combustible.

N. An alkaloid.

Properties: Colorless needles. D 0.833, mp 44C, bp

Properties: White crystals. Mp 182–185C. Insoluble

225C (100 mm Hg), refr index 1.4323 (45C). Insolu-

in water; soluble in alcohol, benzene, chloroform,

ble in water; soluble in benzene and ether.

and slightly soluble in ether.

Derivation: Fractional distillation of mixed coconut

Derivation: From opium.

or other acids.

Hazard: Toxic by ingestion.

Grade: 99.8% pure, technical, FCC.

Use: Medicine (analgesic).

Use: Alkyd resins, wetting agents, soaps, detergents,

cosmetics, insecticides, food additives.

laudanum. Tincture of opium (tinctura opii BP).

lauric aldehyde. See lauryl aldehyde.

laughing gas. See nitrous oxide.

laurone. An aliphatic ketone, insoluble in water,

stable to high temperatures, acids, alkalies. Compat-

ible with high-melting vegetable waxes, fatty acids,

laundry sour. See sour.

paraffins, etc. Incompatible with resins, polymers,

and organic solvents at room temperature, but com-

lauraldehyde. See lauryl aldehyde.

patible with them at high temperature.

Use: As antiblock agent.

lauramidopropyl betaine.

N-lauroyl-p-aminophenol.

CAS: 86438-78-0.

HO(C

)NHCOCH

(CH

)

Hazard: An eye irritant.

Properties: White to off-white powder. Mp

123–126C. Insoluble in water; soluble in polar or-

Laurent’s acid. (1-naphthylamine-5-sulfonic ganic solvents (especially when heated), including

acid). alcohol, acetone, and dimethylformamide.

742LAUROYL CHLORIDE

Use: Rubber antioxidant. Properties: Amber liquid; coconut odor. Low vola-

tility, d 1.026 (25/25C), bp 175C (45 mm Hg), fp

−15.5C, flash p 291F (144C). Insoluble in water;

lauroyl chloride. C

COCl.

soluble in alcohol, ether. Combustible.

Properties: Water-white liquid. Refr index 1.445

Grade: Technical, approximately 60% pure.

(20C), fp −17C, bp 145C (18 mm Hg). Decomposes

Derivation: Coconut oil.

in water and alcohol, soluble in ether.

Use: Intermediate for quaternary ammonium com-

Use: Surfactant, polymerization initiator, antien-

pounds, organometallics, and vinyl stabilizers.

zyme agent, foamer; synthesis of lauroyl peroxide,

sodium N-lauroyl sarcosinate, and other sarcosi-

nates.

lauryl chloride.

Properties: Commercially a mixture of n-alkyl chlo-

(lauroyloxy)tributylstannane. See tributyl-

rides, with C

Cl dominant. A clear, water-white,

tin laurate.

oily liquid; faint fatty odor. Crystallization point

−19C, d 0.863 (15.5/15.5C), distillation range

lauroyl peroxide. (dodecanoyl peroxide).

112–160C (5 mm Hg), flash p 235F (112C). Com-

CAS: 105-74-8. (C

CO)O

pletely miscible with most organic solvents; slightly

Properties: White, coarse powder; tasteless; faint

miscible with alcohol; immiscible with water. Com-

odor. Mp 49C. Soluble in oils and in most organic

bustible.

solvents. Slightly soluble in alcohols. Insoluble in

Grade: Refined, technical.

water.

Use: Synthesis of esters, sulfides, lauryl mercaptan

Grade: Technical (about 95%).

(used in styrene-butadiene polymerization), other

Hazard: Dangerous fire and explosion risk, will ig-

organics.

nite organic materials, strong oxidizer. Toxic by

ingestion and inhalation, strong irritant to skin.

lauryldimethylamine.

Use: Bleaching agent, intermediate and drying agent

CAS: 112-18-5. CH

(CH

)

N(CH

)

. A liquid cat-

for fats, oils, and waxes; polymerization catalyst.

ionic detergent.

Use: Corrosion inhibitor, acid-stable emulsifier.

N-lauroylsarcosine.

(CH

)

CON(CH

)CH

COOH.

lauryldimethylamine oxide.

Properties: White solid. Mp 31–35C, d 0.970.

CAS: 1643-20-5. CH

(CH

)

N(CH

)

•H

O. A non-

Use: Surfactant, antienzyme, in cosmetics and phar-

ionic detergent.

maceuticals. Also used in form of sodium N-lauroyl

Use: As a foam stabilizer; stable at high concentra-

sarcosinate.

tion of electrolytes and over a wide pH range.

See “Admox” [Albemarle].

lauryl acetate. See dodecyl acetate.

lauryl lactate. See “Ceraphyl.”

lauryl alcohol. (alcohol C12; n-dodecanol;

dodecyl alcohol).

lauryl mercaptan. (n-dodecyl mercaptan).

CAS: 112-53-8. CH

(CH

)

OH.

CAS: 112-55-0. C

SH (approximately).

Properties: Colorless solid; fatty repulsive odor. D

Properties: (Technical material, mixture of iso-

0.830–0.836, refr index 1.428, mp 24C, bp 259C,

mers): Water-white or pale-yellow liquid; mild

flash p above 212F (100C) (CC). Insoluble in water;

odor. D 0.85 (20/20C), fp −7.5C, distillation range

soluble in two parts of 70% alcohol. Combustible.

200–235C, refr index 1.45–1.47, flash p 210F

Derivation: Reduction of coconut-oil fatty acids.

(99C). Insoluble in water; soluble in methanol,

Grade: Technical, FCC.

ether, acetone, benzene, gasoline, and ethyl acetate.

Use: Synthetic detergents, lube additives, pharma-

Combustible.

ceuticals, rubber, textiles, perfumes; flavoring

Grade: 95% min.

agent.

Hazard: May be injurious to eyes.

Use: Manufacture of synthetic rubber and plastics,

lauryl aldehyde. (lauric aldehyde; dodecyl

also in the synthesis of pharmaceuticals and in insec-

aldehyde; aldehyde C-12 lauric; dodecanal; lau-

ticides and fungicides; nonionic detergent.

raldehyde).

See thiol.

CAS: 112-54-9. CH

(CH

)

CHO.

Properties: Colorless solid or liquid; strong fatty

floral odor. D 0.828–0.836, refr index 1.433–1.440,

lauryl methacrylate.

mp 44C. Soluble in 90% alcohol; insoluble in water.

CAS: 142-90-5. CH

:C(CH

)COO(CH

)

. The

Combustible.

commercial material is a mixture containing both

Grade: Technical, FCC.

lower and higher fatty derivatives.

Use: Perfumery, flavoring agent.

Properties: Boiling range 272–344C, bulk d 0.868 g/

mL, flash p 270F (132C) (COC). Combustible.

lauryl bromide. (n-dodecyl bromide; 1-bro- Use: Polymerizable monomer for plastics, molding

mododecane). C

Br. powders, solvent coatings, adhesives, oil additives;

743 LEAD

emulsions for textile, leather, and paper finishing. isotope has a half-life of 8 sec. It has been made by

See acrylic resin.

bombarding californium with boron ions. It exhibits

␣ radiation.

lauryl pyridinium chloride. C

NClC

See actinide series.

Properties: Mottled-tan semisolid. Soluble in water

and organic solvents. Flash p 347F (175C). Com-

lay-up. In the reinforced-plastics industry, a term

bustible.

used to refer to placement of the reinforcing material

Grade: Technical, contains higher and lower fatty

in the mold.

acid derivatives.

Use: Cationic detergent, dispersing and wetting

“L-64 Barrier Foaming Quat” [Ace].

agent, ingredient of fungicides and bactericides.

TM for drain and floor protection system.

Use: Floor cleaner for the food industry.

lauryltrimethylammonium chloride.

CAS: 112-00-5. mf: C

N•Cl.

50.

(lethal concentration 50%). That quantity of

Hazard: A poison by ingestion.

a substance administered by inhalation that is neces-

sary to kill 50% of test animals exposed to it within a

lautal. A hard aluminum alloy containing 4–5%

specified time. The test applies not only to gases and

copper, 1.5–2% silicon, and fractional percentages

vapors but to fumes, dusts, and other particulates

of other metals such as iron, manganese, or magne-

suspended in air.

sium.

LCL. Abbreviation for “less than carload lot,”

lava. Molten rock (magma) that has reached the

used by shippers, traffic managers, railroads, etc.

surface of the earth.

50.

(lethal dose 50%). That quantity of a sub-

lavandin oil. See lavender oil.

stance necessary to kill 50% of exposed animals in

laboratory tests within a specified time. A substance

lavender oil.

having an oral LD

of less than 400 mg/kg of body

CAS: 8000-28-0. An essential oil used in perfumery,

weight is considered to be highly toxic.

35% ester content as linalyl acetate required. Terpe-

neless grade has about twice the concentration of the

LDPE. Abbreviation for low-density polyeth-

natural oil.

ylene.

Lavoisier, Antoine Laurent. (1743–1794).

leaching. See solvent extraction.

A French chemist generally regarded as the “father”

of chemistry. His “Traite elementaire de chimie”

lead. (from Latin plumbum).

(1789) listed 30 elements, clarified the nomencla-

CAS: 7439-92-1. Pb. Metallic element of atomic

ture of acids, bases, and salts, and described the

number 82, group IVA of the periodic table, aw

composition of numerous organic substances. He

207.2, valences

2,4, four stable isotopes. The iso-

erroneously believed that oxygen is the characteris-

topes are the end products of the disintegration of

tic element of acids. However, his fundamental

three series of natural radioactive elements uranium

work on combustion, as a result of which he identi-

(206), thorium (208), and actinium (207).

fied and named nitrogen (azote), and on the separa-

Properties: Heavy, ductile, soft, gray solid. D 11.35,

tion of hydrogen from water by a unique reduction

mp 327.4C, bp 1755C. Soluble in dilute nitric acid;

experiment carried out in a heated gun barrel, earned

insoluble in water but dissolves slowly in water

him a leading position among early chemists.

containing a weak acid. Resists corrosion; relatively

See Mendeleyev.

impenetrable to radiation. Poor electrical conductor,

good sound and vibration absorber. Noncombust-

law of mass action. The law stating that the

ible.

rate of any given chemical reaction is proportional to

Occurrence: U.S., Mexico, Canada, South America,

the product of the concentrations of the reactants. At

Australia, Africa, Europe.

extremely low concentrations, activities are used.

Derivation: Roasting and reduction of galena (lead

sulfide), anglesite (lead sulfate), and cerussite (lead

Lawrence, Ernest O. (1901–1958). An

carbonate). Also from scrap.

American physicist who invented the cyclotron in

Method of purification: Desilvering (Parkes pro-

1929. Both the element lawrencium and the Law-

cess), electrolytic refining (Betts process), pyrome-

rence Livermore Research Laboratory at the Uni-

tallurgical refining (Harris process). Bismuth is re-

versity of California were named after him.

moved by Betterton-Kroll process.

See cyclotron; bombardment.

Grade: High purity (less than 10 ppm impurity), pure

(99.9+%), powdered (99% pure), pig lead, paste.

lawrencium. Lr. A synthetic radioactive element Available forms: Ingots, sheet, pipe, shot, buckles or

with atomic number 103, discovered in 1961, aw straps, grids, rod, wire, etc.; paste; powder; single

257, only one other isotope is known (256); the 257 crystals.

744LEAD ACETATE

Hazard: Toxic by ingestion and inhalation of dust or

lead arsenite.

fume. TLV: (fumes and dusts and inorganic com- CAS: 10031-13-7. Pb(AsO

)

pounds) 0.15 mg (Pb)/m

. For ambient air the EPA Properties: White powder. D 5.85. Soluble in nitric

standard is 1.5 ␮g/m

. A cumulative poison. FDA acid; insoluble in water.

regulations require zero lead content in foods and

Hazard: Highly toxic.

less than 0.05% in house paints.

Use: Insecticide.

Use: Storage batteries, tetraethyllead (gasoline addi-

tive), radiation shielding, cable covering, ammuni-

lead azide.

tion, chemical reaction equipment (piping, tank lin-

CAS: 13424-46-9. Pb(N

)

ings, etc.), solder and fusible alloys, type metal,

Properties: Colorless, very sensitive needles. An

vibration damping in heavy construction, foil, Bab-

initiating explosive. Should always be handled sub-

bitt and other bearing alloys.

merged in water.

Derivation: Reaction of sodium azide with a lead

salt.

lead acetate. (sugar of lead).

Hazard: Severe explosion risk, detonates at 350C

CAS: 301-04-2. Pb(C

)

•3H

(660F). Highly toxic. TLV: 0.15 mg(Pb)/m

Properties: White crystals or flakes (commercial

Use: Primary detonating compound for high explo-

grades are frequently brown or gray lumps); sweet-

sives.

ish taste. D 2.50, mp loses water at 75C, at 200C

Note: Explosions have occurred in cases where azide

decomposes, bp (anhydrous) 280C. Absorbs carbon

compounds have reacted with the lead in plumbing

dioxide when exposed to air, becoming insoluble in

after being washed down sinks.

water. Soluble in water; slightly soluble in alcohol;

freely soluble in glycerol. Combustible.

lead-base Babbitt. See Babbitt metal.

Derivation: By the action of acetic acid on litharge or

thin lead plates.

Grade: Powdered, granular, crystals, flakes, CP.

lead biorthophosphate. See lead phosphate,

Hazard: Toxic by ingestion, inhalation, and skin

dibasic.

absorption; use may be restricted.

Use: Dyeing of textiles, waterproofing, varnishes,

lead, blue. A term applied to galena to distin-

lead driers, chrome pigments, gold cyanidation pro-

guish it from white lead ore. It is also applied to blue

cess, insecticide, antifouling paints, analytical re-

basic lead sulfate.

agent, hair dye.

lead borate. Pb(BO

)

•H

lead alkyl, mixed. A mixture containing vari-

Properties: White powder. D 5.598, mp 160C (loses

ous methyl and ethyl derivatives of tetraethyl lead

water). Soluble in dilute nitric acid; insoluble in

and tetramethyl lead. Thus, methyl triethyl lead,

water. Noncombustible.

dimethyl diethyl lead, and ethyl trimethyl lead may

Derivation: Interaction of solutions of lead hydrox-

all be present with or without tetraethyl and tetra-

ide and boric acid with subsequent crystallization.

methyl lead.

Hazard: Toxic by inhalation. TLV: 0.15 mg/m

Hazard: Toxic by ingestion and skin absorption.

Use: Varnish and paint drier, waterproofing paints,

Use: Antiknock agents in aviation gasoline.

lead glass, electrically conductive ceramic coatings.

lead borosilicate. A constituent of optical

lead antimonate. (Naples yellow; antimony

glass, composed of a mixture of the borate and sili-

yellow). Pb

(SbO

)

cate of lead.

Properties: Orange-yellow powder; insoluble in wa-

ter. D 6.58 (20C). Noncombustible.

lead bromate.

Derivation: Interaction of solutions of lead nitrate

CAS: 34018-28-5. Pb(BrO

)

•H

and potassium antimonate, concentration, and crys-

Properties: Colorless crystals. D 5.53, decomposes

tallization.

at about 180C. Soluble in hot water.

Hazard: Toxic by inhalation. TLV: 0.15 mg(Pb)/m

Hazard: Toxic by inhalation or ingestion.

Use: Staining glass, crockery, and porcelain.

lead bromide. PbBr

lead arsenate. (lead orthoarsenate).

Properties: White powder. D 6.66, bp 916C, mp

CAS: 7784-40-9. Pb

(AsO

)

373C. Slightly soluble in hot water; insoluble in

Properties: White crystals. D 5.8, mp 1042C (de-

alcohol.

composes). Soluble in nitric acid; insoluble in water.

Hazard: Toxic by inhalation. TLV: 0.15 mg(Pb)/m

Derivation: By the action of a soluble lead salt on a

solution of sodium arsenate, concentration, and

lead carbolate. See lead phenate.

crystallization.

Hazard: Highly toxic. TLV: 0.15 mg/m

; a carcin-

ogen.

lead carbonate. PbCO

Use: Insecticide, herbicide. See lead carbonate, basic.

745 LEAD FORMATE

lead carbonate, basic. (lead subcarbonate; lead dioxide. (lead oxide, brown; plumbic

white lead; lead flake). 2PbCO

•Pb(OH)

acid, anhydrous; lead peroxide; lead superox-

Properties: White amorphous powder. D 6.86. Solu-

ide).

ble in acids; insoluble in water, decomposes at

CAS: 1309-60-0. PbO

400C. Noncombustible.

Properties: Brown, hexagonal crystals. D 9.375, mp

Derivation: (1) Dutch process. By the corrosion of

290C (decomposition), an oxidizing agent. Soluble

lead buckles in pots by acetic acid and carbon diox-

in glacial acetic acid; insoluble in water and alcohol.

ide generated by the fermentation of waste tanbark.

Derivation: By adding bleaching powder to an alka-

(2) Carter process. By treating very finely divided

line solution of lead hydroxide.

lead in revolving wooden cylinders with dilute ace-

Hazard: Dangerous fire risk in contact with organic

tic acid and carbon dioxide.

materials. TLV: 0.15 mg(Pb)/m

Hazard: Toxic by inhalation. TLV: 0.15 mg(Pb)/m

Use: Oxidizing agent, electrodes, lead-acid storage

Use: Exterior paint pigment, ceramic glazes.

batteries, curing agent for polysulfide elastomers,

textiles (mordant, discharge in dyeing with indigo),

lead chloride. matches, explosives, analytical reagent.

CAS: 7758-95-4. PbCl

Properties: White crystals. D 5.88, mp 498C, bp

lead dross. (lead scrap). Consists of the scrap,

950C. Slightly soluble in hot water; insoluble in

dross, or waste from sulfuric acid tanks; a mixture of

alcohol and cold water. Noncombustible.

metallic lead, lead sulfate, and free sulfuric acid.

Derivation: By the addition of hydrochloric acid or

sodium chloride to a solution of a lead salt with

lead, electrolytic. Pure lead obtained by elec-

subsequent crystallization.

trolytic deposition.

Hazard: Toxic by inhalation. TLV: 0.15 mg(Pb)/m

See Betts process.

Use: Preparation of lead salts, lead chromate pig-

ments, analytical reagent.

leader. A short sequence near the amino terminus

of a protein or the 5a

′

end of an RNA molecule that

lead chromate. (chrome yellow).

has a specialized targeting or regulatory function.

CAS: 7758-97-6. PbCrO

Often the leader is cleaved after the targeting event.

Properties: Yellow crystals. D 6.123, mp 844C. Sol-

uble in strong acids and alkalies; insoluble in water.

lead flake. See lead carbonate, basic.

Derivation: Reaction of sodium chromate and lead

nitrate in solution.

lead fluoborate.

Hazard: Toxic by ingestion and inhalation; suspect-

CAS: 13814-96-5. B

•Pb.

ed human carcinogen. TLV: 0.05 mg(Cr)/m

; Hu-

Properties: Liquid. Mw 380.81.

man Carcinogen.

Grade: Technical 51%.

Use: Pigment in industrial paints, rubber, plastics,

Hazard: TLV: 0.15 mg(Pb)/m

ceramic coatings; organic analysis.

Use: Salt for electroplating lead; can be mixed with

See chrome pigment.

stannous fluoborate to electroplate any composition

of tin and lead as an alloy.

lead coating. Coatings of lead or lead-rich al-

loys are (1) deposited by dipping into the molten

lead fluoride.

metal after applying a layer of tin to secure good

CAS: 7783-46-2. PbF

adhesion of the lead coating, (2) by electroplating

Properties: Colorless crystals. D 8.2 g/cc, mp (ap-

from a fluosilicate or fluoborate bath, or (3) by

proximately) 824C. Very slightly soluble in water.

spraying.

Noncombustible.

Grade: Crystals, 99.93%.

lead cyanide. Hazard: Toxic. Strong irritant. TLV: 0.15 mg(Pb)/

CAS: 592-05-2. Pb(CN)

Properties: White to yellowish powder. Slightly sol- Use: Electronic and optical applications, starting ma-

uble in water; decomposes in acid. terials for growing single crystal solid-state lasers,

Derivation: Interaction of solutions of potassium high-temperature dry film lubricants in the form of

cyanide and lead acetate. ceramic-bonded coatings.

Hazard: Toxic by ingestion, inhalation, and skin

absorption. TLV: 0.15 mg(Pb)/m

lead fluosilicate. (lead silicofluoride).

Use: Metallurgy.

CAS: 25808-74-6. PbSiF

•2H

Properties: Colorless crystals. Soluble in water; de-

composes when heated.

lead dimethyldithiocarbamate.

Hazard: Toxic. Strong irritant. TLV: 0.15 mg(Pb)/

CAS: 19010-66-3. Pb[SCSN(CH

)

]

Properties: White powder. D 2.43, melting range

Use: Solution for electrorefining lead.

310C. Insoluble in all common organic solvents;

slightly soluble in cyclohexanone.

Use: Vulcanization accelerator with litharge.

lead formate. Pb(CHO

)

746LEAD GLASS

Properties: Brownish-white lustrous needles. D solution of ammonium molybdate, concentration,

4.63. Soluble in water; decomposes at 190C. Non- and crystallization.

combustible. Hazard: Toxic material. TLV: 0.15 mg(Pb)/m

Hazard: Toxic by ingestion.

Use: Analytical chemistry, pigments. Single crystals

Use: Reagent in analytical determinations.

are available for electronic and optical uses.

See molybdate oranges.

lead glass. See glass.

lead monohydrogen phosphate. See lead

lead hydroxide. (lead hydrate; hydrated lead

phosphate, dibasic.

oxide). Pb(OH)

Properties: White, bulky powder. D 7.592, mp de-

lead mononitroresorcinate.

composes at 145C, absorbs carbon dioxide from air.

CAS: 51317-24-9. PbO

Soluble in alkalies; slightly soluble in water; soluble

Hazard: An initiating explosive, dangerous. Forbid-

in nitric and acetic acids. Noncombustible.

den for transport.

Derivation: By the addition of sodium or ammonium

hydroxide to a solution of a lead salt with subsequent

lead monoxide. See litharge, massicot.

filtration and drying.

Hazard: Toxic material. TLV: 0.15 mg(Pb)/m

lead ␤-naphthalenesulfonate.

Use: Lead salts, lead dioxide.

Pb(C

)

Properties: White, crystalline powder. Soluble in

lead hyposulfite. See lead thiosulfate.

alcohol; insoluble in water. Combustible.

Derivation: By the action of lead acetate on ␤-na-

leading strand. The DNA strand that, during

phthalenesulfonic acid.

replication, is synthesized in the same direction in

Hazard: Toxic material. Absorbed by skin.

which the replication fork moves. Synthesized in a

Use: Organic preparations.

continuous fashion.

lead naphthenate.

lead iodide. PbI

CAS: 61790-14-5. C

•xPb.

Properties: Golden-yellow crystals or powder;

Properties: Soft, yellow, resinous, semitransparent.

odorless. D 6.16, mp 402C, bp 954C. Soluble in

Mp approximately 0C. Gives deposits in highly acid

potassium iodide and concentrated sodium acetate

oils but not when mixed with suitable quantities of

solutions; soluble in boiling water. Noncombust-

cobalt or manganese; soluble in alcohol. Combus-

ible.

tible.

Derivation: Interaction of lead acetate and potassi-

Derivation: Addition of lead salt to aqueous sodium

um iodide.

naphthenate solution.

Hazard: Toxic material. TLV: 0.15 mg(Pb)/m

Grade: liquid 16%, 24% lead, solid 37% lead.

Use: Bronzing, printing, photography, cloud seeding.

Hazard: Toxic material. A known carcinogen

(OSHA), absorbed by skin.

lead linoleate. (lead plaster). Pb(C

)

Use: Paint and varnish drier, wood preservative, in-

Properties: Yellowish-white paste. Soluble in oils;

secticide, catalyst for reaction between unsaturated

insoluble in water. Combustible.

fatty acids and sulfates in the presence of air, lube oil

Derivation: By heating a solution of lead nitrate with

additive.

sodium linoleate.

See soap (2).

Grade: Technical, fused (contains 26.5% lead).

Hazard: Toxic material. Absorbed by skin.

lead nitrate.

Use: Medicine, drier in paints and varnishes.

CAS: 10099-74-8. Pb(NO

)

Properties: White crystals. D 4.53, decomposes at

lead maleate, tribasic. C

•Pb.

470C. Soluble in water and alcohol.

Properties: Soft, yellowish-white, crystalline pow-

Derivation: By the action of nitric acid on lead.

der. D 6.3, refr index 2.08.

Hazard: Strong oxidizing material, dangerous fire

Hazard: Toxic material. Absorbed by skin.

risk in contact with organic materials. TLV: 0.15

Use: Vulcanizing agent for chlorosulfonated poly-

mg(Pb)/m

ethylene. Highly basic stabilizer with high heat sta-

Use: Lead salts, mordant in dyeing and printing cali-

bility in vinyls.

co, matches, mordant for staining mother-of-pearl,

oxidizer in the dye industry, sensitizer in photogra-

lead metavanadate. See lead vanadate.

phy, explosives, tanning, process engraving, and

lithography.

lead molybdate. PbMoO

Properties: Yellow powder. D 5.9, mp 1060–1070C.

Soluble in nitric acid; insoluble in water and alcohol.

lead nitrite, basic. (basic lead nitrite; lead

Noncombustible. subnitrite).

Derivation: By adding a solution of lead nitrate to a Properties: Light-yellow powder, variable composi-

747 LEAD RESINATE

tion, essentially 3PbO•N

O•H

O. Soluble in dilute lead phenate. (lead phenolate; lead carbo-

nitric acid; easily decomposed. late). Pb(OH)OC

Hazard: Toxic material. TLV: 0.15 mg(Pb)/m

. Properties: Yellowish to grayish-white powder. Sol-

uble in nitric acid; insoluble in water and alcohol.

Derivation: By boiling phenol with litharge.

lead ocher. See massicot (1).

Hazard: Toxic material. Absorbed by skin.

lead octoate. See soap (2).

lead phenolsulfonate. (lead sulfocarbolate).

Pb(C

OHSO

)

•5H

lead oleate.

Properties: White crystals or powder. Soluble in

CAS: 1120-46-3.

water and alcohol.

[CH

(CH

)

CH:CH(CH

)

COO]

Pb.

Hazard: Toxic material. Absorbed by skin.

Properties: White powder or ointment-like granules

or mass. Soluble in alcohol, ether, turpentine, and

lead phosphate. (normal lead orthophosp-

benzene; insoluble in water. Combustible.

hate).

Derivation: Reaction of oleic acid with lead hydrate

CAS: 7446-27-7. Pb

(PO

)

or carbonate, or of lead acetate and sodium oleate.

Properties: White powder. D 6.9–7.3, mp 1014C.

Hazard: Toxic material. Absorbed by skin.

Insoluble in water; soluble in acids and alkalies.

Use: Varnishes, lacquers, paint drier, high-pressure

Hazard: Toxic material. TLV: 0.15 mg(Pb)/m

lubricants.

Use: Stabilizing agent in plastics.

See soap (2).

lead phosphate, dibasic. (lead monohydro-

lead orthoarsenate. See lead arsenate.

gen phosphate; lead biorthophosphate). PbHPO

Properties: Soft, white powder or fine, platelike

lead orthophosphate, normal. See lead

crystals. D 5.66 (15C), mp decomposes.

phosphate.

Hazard: Toxic material. TLV: 0.15 mg(Pb)/m

Use: Imparting heat resistance and pearlescence to

lead orthosilicate. See lead silicate.

polystyrene and casein plastics.

lead phosphite, dibasic.

lead oxide, black. See lead suboxide.

CAS: 1344-40-7. 2PbO•PbHPO

•1/2H

Properties: Fine, white, acicular crystals. D 6.94,

lead oxide, brown. See lead dioxide.

refr index 2.25. Insoluble in water.

Hazard: Toxic material. TLV: 0.15 mg(Pb)/m

lead oxide, hydrated. See lead hydroxide.

Store in closed containers away from open flame or

sparks and at temperatures not to exceed 400F.

lead oxide, red. (red lead; minium; lead

Use: Heat and light stabilizer for vinyl plastics and

tetroxide).

chlorinated paraffins. As an UV screening and anti-

CAS: 1314-41-6. Pb

oxidizing stabilizer for vinyl and other chlorinated

Properties: Bright red powder. D reported variously

resins in paints and plastics.

8.32–9.16, decomposes between 500 and 530C.

Partly soluble in acids; insoluble in water. An oxi-

lead phthalate, dibasic.

dizing agent, may react with reducing agents.

(COO)

Pb•PbO.

Derivation: By carefully heating litharge in a furnace

Properties: Fluffy white crystalline powder. D 4.5,

in a current of air.

refr index 1.99 (avg). Insoluble in water.

Grade: Technical, 95%, 97%, 98%.

Derivation: By boiling litharge with phthalic acid.

Hazard: Toxic as dust. TLV: 0.15 mg(Pb)/m

Hazard: Toxic by inhalation and skin absorption.

Use: Storage batteries, glass, pottery and enameling,

Use: Heat and light stabilizer for general vinyl use.

varnish, purification of alcohol, packing pipe joints,

metal-protective paints, fluxes, and ceramic glazes.

lead plaster. See lead linoleate.

lead oxide, yellow. See litharge.

lead protoxide. See litharge.

lead perchlorate.

lead, red. See lead oxide, red.

CAS: 13637-76-8. Pb(ClO

)

•3H

Properties: White crystals. D 2.6, mp 100C (decom-

lead resinate. Pb(C

)

poses). Very soluble in cold water; soluble in al-

Properties: Brown, lustrous, translucent lumps or

cohol.

yellow-white powder, or yellowish-white paste. In-

Hazard: Dangerous in contact with organic materi-

soluble in most solvents. Combustible.

als, strong oxidizing agent. Very toxic material.

Derivation: By heating a solution of lead acetate and

rosin oil.

lead peroxide. See lead dioxide. Grade: Precipitated 23% lead.

748LEAD SALICYLATE

Hazard: Toxic material. Absorbed by skin. um temperatures, but become somewhat fluid on

Use: Paint and varnish drier, textile waterproofing heating by friction.

agent. Use: “Extreme-pressure lubricants,” but are not suit-

ed for high speeds.

See lead naphthenate; lead oleate; lead stearate; soap

lead salicylate. Pb(OOCC

OH)

•H

(2).

Properties: Soft, creamy-white, crystalline powder.

D 2.3, refr index 1.78. Soluble in hot water and

lead sodium hyposulfite. See lead sodium

alcohol. Combustible.

thiosulfate.

Use: Stabilizer or costabilizer for flooring and other

vinyl compounds requiring good light stability.

lead sodium thiosulfate. (lead sodium hy-

posulfite; sodium lead hyposulfite; sodium lead

lead selenide. PbSe.

thiosulfate). PbS

•2Na

Properties: Gray crystals. D 8.10 (15C), mp 1065C.

Properties: Heavy, small, white crystals. Soluble in

Insoluble in water; soluble in nitric acid.

solutions of thiosulfates.

Hazard: Moderate fire hazard as dust or in presence

Hazard: Toxic material. TLV: 0.15 mg(Pb)/m

of moisture. TLV: 0.15 mg(Pb)/m

Use: Matches.

Use: As a semiconductor in infrared detectors and

thermoelectric devices.

lead stannate. PbSnO

•2H

Properties: Light-colored powder. Insoluble in wa-

lead sesquioxide. Pb

ter. Approximate temperature of dehydration 170C.

Properties: Reddish-yellow powder. Soluble in al-

Hazard: Toxic material. TLV: 0.15 mg(Pb)/m

kalies and acids; insoluble in water; decomposes at

Use: Additive in ceramic capacitors, pyrotechnics.

370C.

Derivation: By gently heating metallic lead.

Hazard: Toxic material. TLV: 0.15 mg(Pb)/m

. lead stearate.

Use: Ceramics, ceramic cements, metallurgy, var- CAS: 7428-48-0. Pb(C

)

nishes. Properties: White powder. Mp 100–115C, d 1.4.

Soluble in hot alcohol; insoluble in water. Combus-

tible.

lead silicate. (lead metasilicate).

Derivation: By heating a solution of lead acetate

CAS: 10099-76-0. PbSiO

with sodium stearate.

Properties: White, crystalline powder. Insoluble in

Hazard: Toxic material. Absorbed by skin.

most solvents. Noncombustible.

Use: Varnish and lacquer drier, high-pressure lubri-

Derivation: Interaction of lead acetate and sodium

cants, lubricant in extrusion processes, stabilizer for

silicate.

vinyl polymers, corrosion inhibitor for petroleum,

Hazard: Toxic material. TLV: 0.15 mg(Pb)/m

component of greases, waxes, and paints.

Use: Ceramics, fireproofing fabrics.

lead styphnate. Legal label name for lead trini-

lead silicate, basic. (white lead silicate; lead

troresorcinate.

silicate sulfate). A pigment made up of an adherent

surface layer of basic lead silicate and basic lead

sulfate cemented to silica.

lead subacetate.

Properties: Excellent film-forming properties with CAS: 1335-32-6. (2Pb(OH)

Pb(C

)

drying oils combined with low density. Properties: White, heavy powder. Mw 807.75. Par-

Derivation: Fine silica is mixed with litharge and tially soluble in cold water; more soluble in hot

sulfuric acid. The mixture is then furnaced in a water; absorbs atmospheric carbon dioxide becom-

rotary kiln and ground to break up agglomerates. ing almost insoluble.

Hazard: Toxic material. TLV: 0.15 mg(Pb)/m

. Hazard: Suspected carcinogen and poisonous. Toxic

Use: Pigment in industrial paints. by ingestion.

Use: Decolorizing agent (sugar solutions, etc.).

lead silicochromate. A yellow, lead-silicon

pigment. Normal lead silicon chromate is used as a

lead subcarbonate. See lead carbonate,

yellow prime pigment for traffic marking paints. basic.

Basic lead silicon chromate is used as a corrosive

inhibitive pigment for metal protective coatings,

lead subnitrite. See lead nitrite.

primers and finishers. Also for industrial enamels

requiring a high gloss.

lead suboxide. (lead oxide, black; litharge,

Hazard: Toxic material. TLV: 0.15 mg(Pb)/m

leaded). Pb

Properties: Black amorphous material. D 8.342, de-

lead silicofluoride. See lead fluosilicate.

composes on heating. Insoluble in water; soluble in

acids and bases.

lead-soap lubricants. Lead salts saponified Hazard: Toxic material. TLV: 0.15 mg(Pb)/m

with fats, hard at low temperatures, viscous at medi- Use: In storage batteries.

749 LEAD THIOSULFATE

lead, sugar of. See lead acetate. Hazard: Toxic by ingestion and inhalation. TLV:

0.15 mg(Pb)/m

Use: Ceramics, infrared radiation detector, semicon-

lead sulfate.

ductor, ceramic glaze, source of lead.

CAS: 7446-14-2. PbSO

Properties: White, rhombic crystals. D 6.12–6.39,

lead sulfite. PbSO

mp 1170C. Slightly soluble in hot water; insoluble

Properties: White powder. Decomposes on heating.

in alcohol; soluble in sodium hydroxide solution and

Insoluble in water; soluble in nitric acid.

concentrated hydriodic acid. Noncombustible.

Hazard: Toxic by ingestion and inhalation. TLV:

Derivation: Interaction of solutions of lead nitrate

0.15 mg(Pb)/m

and sodium sulfate.

Hazard: Strong irritant to tissue. TLV: 0.15 mg(Pb)/

lead sulfocarbolate. See lead phenolsulfo-

Use: Storage batteries, paint pigments.

nate.

lead sulfocyanide. See lead thiocyanate.

lead sulfate, basic. (white lead, sublimed;

white lead sulfate). Approximate formula

lead superoxide. See lead dioxide.

PbSO

•PbO.

Properties: White, monoclinic crystals. D 6.92, mp

977C. Slightly soluble in hot water or acids. Non-

lead tallate. A mixture of lead and tall oil. Com-

combustible.

bustible.

Grade: Vary from 72–85% lead sulfate and remain-

Grade: Liquid: 16% lead, 24% lead: solid: 30% lead.

der lead oxide. Sold dry or ground in oil.

Derivation: By the fusion process.

Derivation: Three methods are used: (1) lead sulfide

Hazard: Toxic material. Absorbed by skin.

ore (galena) is subjected to high temperatures in an

See soap (2).

oxidizing atmosphere; (2) molten lead is sprayed

into a jet of ignited fuel gas and air in the presence of

lead telluride. PbTe.

sulfur dioxide gas; (3) atomized metallic lead is

Properties: Crystalline solid. D 8.2, mp 905C. Insol-

mixed with water, and sulfuric acid is added under

uble in water and most acids.

controlled conditions.

Hazard: Toxic by ingestion and inhalation. TLV:

Hazard: Toxic material. TLV: 0.15 mg(Pb)/m

0.15 mg(Pb)/m

Use: Paints, ceramics, pigments.

Use: Single crystals used as photoconductor and

semiconductor in thermocouples.

lead sulfate, blue basic. (sublimed blue

lead; blue lead). Composition: Lead sulfate (min)

lead tetraacetate. Pb(CH

COO)

45%, lead oxide (min) 30%, lead sulfide (max) 12%,

Properties: Colorless or faintly pink crystals, some-

lead sulfite (max) 5%, zinc oxide 5%, carbon and

times moist with glacial acetic acid. Mp 175C, d

undetermined matter (max) 5%.

2.228 (17C). Soluble in benzene, chloroform, nitro-

Properties: Blue-gray, corrosion-inhibiting pig-

benzene, hot glacial acetic acid. Combustible.

ment. D 6.2. Insoluble in water or alcohol. Noncom-

Derivation: From red lead (Pb

) and glacial acetic

bustible.

acid in the presence of acetic anhydride.

Derivation: By heating lead ores in special furnaces.

Hazard: Toxic material. Absorbed by skin.

Hazard: Toxic material. TLV: 0.15 mg(Pb)/m

Use: Oxidizing agent in organic synthesis, laboratory

Use: Component of structural-metal priming coat

reagent.

paints, rust-inhibitor in paints, lubricants, vinyl plas-

tics, and rubber products.

lead tetraethyl. See tetraethyl lead.

lead sulfate, tribasic. 3PbO•PbSO

•H

lead tetroxide. See lead oxide, red.

Properties: Fine, white powder. D 6.4, refr index 2.1.

Hazard: Toxic material. TLV: 0.15 mg(Pb)/m

lead thiocyanate. (lead sulfocyanate).

Use: Electrical and other vinyl compounds requiring

CAS: 592-87-0. Pb(SCN)

high heat stability.

Properties: White or light-yellow crystalline pow-

der. D about 3.8. Soluble in potassium thiocyanate,

nitric acid; slightly soluble in cold water; decom-

lead sulfide. (plumbous sulfide).

poses in hot water.

CAS: 1314-87-0. PbS.

Hazard: Toxic by ingestion and inhalation. TLV:

Properties: Silvery, metallic crystals or black pow-

0.15 mg(Pb)/m

der. D 7.13–7.7, mp 1114C, sublimes at 1281C.

Use: Ingredient of priming mix for small-arms car-

Soluble in acids; insoluble in water and alkalies.

tridges, safety matches, dyeing.

Derivation: (1) Found in nature as the mineral gale-

na, (2) by passing hydrogen sulfide gas into an acid

solution of lead nitrate.

lead thiosulfate. (lead hyposulfite). PbS

Grade: Technical, CP, electronic. Properties: White crystals. D 5.18, mp decomposes.

750LEAD TITANATE

Soluble in acids and sodium thiosulfate solution; Use: Element in high fidelity stereo units and as a

insoluble in water.

transducer for ultrasonic cleaners, ferroelectric ma-

Derivation: By the interaction of solutions of lead

terials in computer memory units.

nitrate and sodium thiosulfate, concentration, and

crystallization.

leaf, filter. A unit of a shell-and-leaf filter press

Hazard: Toxic by ingestion and inhalation. TLV:

on which the cake is formed. In general, a leaf

0.15 mg(Pb)/m

consists of a circular or rectangular metal frame in

which is fastened a coarse wire screen. This is cov-

lead titanate. PbTiO

ered on both sides with a fine-mesh wire cloth, over

Properties: Pale-yellow solid. D 7.52. Insoluble in

which is placed the filter medium proper, e.g., nylon

water.

fabric. The filtrate passes through the fabric and into

Derivation: Interaction of oxides of lead and titani-

an escape pipe to the discharge port. Each shell may

um at a high temperature. Contains lead sulfate and

contain as few as six or as many as 50 leaves of

lead oxide as impurities.

varying dimensions; the entire assembly can be

Hazard: Toxic by ingestion and inhalation. TLV:

pulled out of the shell for cake removal. In some

0.15 mg(Pb)/m

models the leaves rotate.

Use: Industrial paint pigment.

leafseal. A a formulation of decenylsuccinic acid

lead trinitroresorcinate. (lead styphnate).

and its esters.

CAS: 63918-97-8. C

H(NO

)

Pb).

Use: Direct application to plants to enable them to

Properties: Monohydrate is monoclinic orange-yel-

resist frost and drought.

low crystals. D 3.1 (monohydrate), 2.9 (anhydrous).

Practically insoluble in water.

leather. An animal skin or hide that has been

Derivation: Prepared by adding a solution of magne-

permanently combined with a tanning agent that

sium styphnate (from magnesium oxide and styph-

causes a physicochemical change in the protein

nic acid) to a lead salt solution.

components of the skin. This change renders it resis-

Hazard: Detonates at 500F (260C), dangerous ex-

tant to putrefactive bacteria, enzymes, and hot wa-

plosion risk, an initiating explosive.

ter, increases its strength and abrasion resistance,

and makes it serviceable for long periods of time.

lead, tris(lauroyloxy)phenyl-. See phenyl-

Tanning agents are either vegetable, mineral, or

lead trilaurate.

synthetic. Hides from cows or steers are chiefly used

for men’s shoes, transmission belting, and other

lead tungstate. (lead wolframate). PbWO

heavy-duty service. These are usually vegetable-

Properties: White powder. D 8.235, mp 1130C. Sol-

tanned. Lighter grades made from the skins of sheep,

uble in sodium hydroxide solutions; insoluble in

calves, or reptiles are used for shoe uppers, luggage,

water.

gloves, and similar end products (chrome-tanned).

Derivation: By mixing solutions of lead nitrate and

Leather is a naturally poromeric material that retains

sodium tungstate, concentrating, and crystallizing.

the microporosity of the original skin; this property

Hazard: Toxic material. TLV: 0.15 mg(Pb)/m

makes it uniquely applicable to footwear; to a limit-

Use: Pigment.

ed extent it is able to conform to the contour of the

individual foot. Leather is made in many colors,

lead vanadate. (lead metavanadate).

weights, and finishes. However, it has been replaced

Pb(VO

)

to an increasing extent by plastics for many minor

Properties: Yellow powder. Insoluble in water; de-

uses, and by synthetics for shoe uppers and soling.

composes in nitric acid.

See poromeric; tanning.

Hazard: Toxic material. TLV: 0.15 mg(Pb)/m

Use: Preparation of other vanadium compounds, pig-

leavening agent. See yeast; baking powder.

ment.

Lebedev process. Formation of butadiene from

lead water. A 1% solution of basic lead acetate.

ethanol by catalytic pyrolysis. The catalysts used are

Hazard: Toxic. See lead acetate.

mixtures of silicates and aluminum and zinc oxides.

lead, white. See lead carbonate, basic; lead

Le Blanc. (1742–1806). A French inventor of

silicate, basic; and lead sulfate, basic.

the first successful process for making soda ash. His

patent was confiscated by the Revolutionist govern-

lead wolframate. See lead tungstate.

ment, and the process was used widely for years

without either acknowledgment or remuneration.

lead wool. Fine filaments or threads of metallic

His original formula was 100 parts salt cake, 100

lead, prepared and used for packing pipe joints.

parts limestone, and 50 parts coal.

lead zirconate titanate. (LZT). PbTiZrO

Available forms: Piezoelectric crystals.

Lechanche cell. See dry cell.

751 LEHMSTEDT-TANASESCU

Le Chatelier. (1850–1936). A French physical Herschbach. A former student of Herschbach, Lee

chemist, famous chiefly for his statement of the refined molecular-beam and laser techniques, com-

bining them with theory to perform definitive stud-

equilibrium principle (often known as Le Chateli-

ies of reactions of individual complex molecules.

er’s law). His work included investigations of ce-

Doctorate from University of California in 1965.

ments, alloys, and gaseous combustion. The princi-

ple may be stated: every system in equilibrium is

conservative and tends to resist changes upon it by

legal chemistry. (forensic chemistry). The ap-

reacting in such a way as to help nullify the imposed

plication of chemical knowledge and procedures to

change.

matters involving civil or criminal law and to all

questions where control of chemical compounds,

“Lecisun” [Lucas Meyer]. TM for a skin

products, or processes is vested in agencies of Fed-

friendly mineral sunscreen.

eral or state governments. Legal chemistry applies

to the following areas:

lecithin. C

NRR

′

, R and R

′

being fatty acid

(1) Crime detection: primarily identification of poi-

groups. Pure lecithin is a phosphatidyl choline. The

sons, of bloodstains, writing and typewriter inks,

lecithins are mixtures of diglycerides of fatty acids

and a host of miscible materials such as textile fibers

linked to the choline ester of phosphoric acid. The

from clothing, hair, skin, etc. A variety of analytical

lecithins are classed as phosphoglycerides or phos-

methods are used in police laboratories, including

phatides (phospholipids). Commercial lecithin is a

microscopes, spot tests, color reactions, and spectro-

mixture of acetone-insoluble phosphatides. FCC

photometry.

specifies not less than 50% acetone-insoluble matter

(2) Food, drugs, and cosmetics are under the control

(phosphatides).

of the U.S. Food and Drug Administration. New

Properties: Light brown to brown, viscous semili-

products and proposed additives must be submitted

quid with a characteristic odor. Partly soluble in

by the manufacturer and approved before being

water and acetone; soluble in chloroform and ben-

placed on public sale. Control of the manufacture of

zene.

illicit drugs is an important phase of legal chemistry.

Derivation: Usually from soybean oil, also from

(3) Pesticides are subject to Federal regulation. New

corn, other vegetable seeds, egg yolk, and other

products must be registered, labeling must be specif-

animal sources.

ic as to chemical composition, active and inert ingre-

Grade: Technical, unbleached, bleached; fluid, plas-

dients, and directions for use.

tic, edible, FCC, 96+% for biochemical or chroma-

(4) Marketing and competitive pricing of chemical

tographic standards.

products’ fair trade agreements and discriminatory

Use: Emulsifying, dispersing, wetting, penetrating

practices are also under Federal supervision (Robin-

agent, and antioxidant; in margarine, mayonnaise,

son-Patman Act). This includes mergers, tie-in

chocolate and candies, baked goods, animal feeds,

sales, and other merchandising practices.

paints, petroleum industry (drilling, leaded gaso-

(5) Interstate shipment and labeling of hazardous

line), printing inks, soaps and cosmetics, mold re-

chemicals is regulated by the Department of Trans-

lease for plastics, blending agent in oils and resins,

portation and the Federal Aviation Agency as well

rubber processing, lubricant for textile fibers.

as by state and local laws. See labeling, toxi-

cology.

lectin. A type of protein occurring in the seeds of

(6) Patent law comprises a vast body of legal prac-

certain plants, especially legumes, characterized by

tice and court decisions. The patent system is de-

unusual binding specificity; their precise function in

signed to protect inventions and new discoveries,

the plant is being researched. Studies have been

and most chemical companies retain legal counsel in

made on the molecular structure and carbohydrate

this field.

content of the lectin found in the European herb

(7) Water pollution is subject to federal regulations

sainfoin.

(Federal Water Pollution Control Act, 1956). This

covers the discharge of contaminating industrial

Leduc’s rule. States that the volume occupied

waste, sewage, oil, etc., into navigable streams and

by a gas mixture is equal to the sum of the volumes

their tributaries as well as into coastal waters.

occupied separately by each constituent at the same

(8) Flammability of fabrics.

temperature and pressure as the mixture.

(9) Use of volatile, toxic solvents on an industrial

scale.

LEED. Low-energy electron diffraction.

(10) Air pollution including gases and particulates

from industrial stacks and auto exhaust emissions.

lees. The sediment at bottom of wine storage tank.

Leeuwenhoek, van. See van Leeuwenhoek,

Lehmstedt-Tanasescu reaction. Preparation

Anton.

of acridones (and 10-hydroxyacridones) from o-ni-

trobenzaldehyde and a halobenzene in the presence

Lee, Yuan T. (1936– ). Awarded Nobel Prize of concentrated sulfuric acid containing nitrous acid

in chemistry in 1986 jointly with Polanyi and as catalyst.

752LEHN, JEAN-MARIE PIERRE

Lehn, Jean-Marie Pierre. (1939– ). Award- lepicidin a.

ed Nobel Prize for chemistry, together with Cram, in CAS: 131929-60-7. mf: C

1987 for work in elucidating mechanisms of molec- Hazard: Moderately toxic by ingestion and inhala-

ular recognition, which are fundamental to the enzy-

tion.

mic catalysis, regulation, and transport. He also

studied three-dimensional cyclic compounds that

lepidine. (␥-methylquinoline; cincholepidine).

maintained a rigid structure, accepting substrates in

CAS: 491-35-0. C

NCH

. An alkaloid.

a structurally preorganized cavity. Lehn named

Properties: Oily liquid; quinoline-like odor. Turns

these compounds cryptands, while Cram called

red-brown on exposure to light. D 1.086, bp 266C,

them cavitands. Awarded Doctorate by University

solidifies at about 0C, soluble in alcohol, ether, and

of Strasbourg, France in 1963.

benzene. Slightly soluble in water.

Derivation: From cinchonine.

Use: Organic preparations, medicine.

lehr. A long oven designed for controlled slow

cooling of glass (annealing). The hot glass is carried

lepidolite. (lithia mica). K

(OH,F)

through the lehr on a conveyor at a predetermined

A fluosilicate of potassium, lithium, and aluminum,

rate, traversing areas of gradually decreasing tem-

found in pegmatites. Rubidium occurs as an impuri-

perature. The entire process may require several

ty. A variety of mica.

days.

Properties: Pink and lilac to gray color; pearly luster;

See annealing.

perfect micaceous cleavage. Mohs hardness 2.5–4, d

2.8–3.0.

Leloir, Luis F. (1906–1987). A French-born

Occurrence: California, South Dakota, New Mexi-

biochemist who won the Nobel Prize for chemistry

co, South Africa.

in 1970 for work in biosynthesis of carbohydrates.

Use: Source of lithium and rubidium, flux in glass

He discovered chemical compounds that affect the

and ceramics production.

storage of chemical energy in humans and animals.

He headed the Department of Biochemistry at the

lethal mutation. A mutation that inactivates a

University of Buenos Aires for many years.

biological function essential to the life of the cell or

organism.

“Lemol” [Borden]. TM for a series of polyvi-

nyl alcohols in partially and fully hydrolyzed form at

“Lethane” [Rohm & Haas]. TM for a group

various molecular weights. Supplied as nondusting,

of thiocyanate insecticides. 60:2-thiocyanoethyl

white granules with d 1.2–1.3.

laurate. 384:␤-butoxy-␤

′

-thiocyanodiethyl ether. A-

Use: Adhesives, emulsions, polymerization, film

70 diethylene glycol dithiocyanate.

coatings, polyester release agents, textile printing,

Hazard: Toxic by ingestion.

finishing, and sizing.

Letts nitrile synthesis. Formation of nitriles

lemon chrome. See barium chromate.

by heating aromatic carboxylic acids with metal

thiocyanates.

lemongrass oil. (verbena oil, Indian). An es-

Leu. Abbreviation for leucine.

sential oil obtained by steam distillation of a grass

(Cymbopogon).

leucine. (␣-amino-␥-methylvaleric acid; ␣-am-

Properties: Dark-yellow to light-brown-red; pro-

inoisocaproic acid).

nounced heavy lemonlike odor. D 0.900–0.910 (15/

CAS: 61-90-5. (CH

)

CHCH

CH(NH

)COOH. An

15C), optical rotation −3 to +1 degrees, refr index

essential amino acid. Found naturally in the

L(−)

1.4830–1.4890 (20C). Soluble in alcohol; slightly

form.

soluble in glycerol. Combustible.

Properties: White crystals. Soluble in water; slightly

Source: India, East and West Indies, Guatemala.

soluble in alcohol; insoluble in ether. Optically ac-

Chief constituents: Citral (75–85%), geraniol,

tive (natural form).

DL-leucine mp 332C with de-

ethylheptenone.

composition;

L(−)-leucine mp 295C, d 1.239 (18/

Use: Perfumes, flavoring, isolates and ionones,

4C).

source of citral.

Derivation: Hydrolysis of protein (edestin, hemo-

globin, zein), organic synthesis from the ␣-bromo

lemon oil. See citrus peel oils.

acid.

Grade: Commercial (

DL), FCC (L-).

lenacil. C

Use: Nutrient and dietary supplement, biochemical

Properties: Colorless solid. Mp 315C, d 1.32. Al-

research.

most insoluble in water; soluble in pyridine.

Use: Herbicide.

leucine zipper. A motif found in certain pro-

teins in which Leu residues are evenly spaced

lentagran. See fenpyrate. through an ␣-helical region, such that they would

753 LEWIS ACID

end up on the same face of the helix. Dimers can Use: Electrical appliances, automotive trim, plumb-

form between two such proteins. The Leu zipper is ing fixtures.

important in the function of transcription factors

such as Fos and Jun and related proteins.

Levene-Hudson phenylhydrazide rule.

The direction of rotation of the phenylhydrazides

Leuckart thiophenol reaction. Decomposi-

of the sugar acids indicates the configuration of the

tion of diazoxanthates by warming gently in faintly

hydroxyl on the ␣-carbon atom. If the phenylhydra-

acidic cuprous media to the corresponding aryl xant-

zide rotates to the right, the hydroxyl on the ␣-car-

hates which produce aryl thiols on alkaline hydroly-

bon is to the right, and vice-versa. The rule was

sis and aryl thioethers on warming.

shown to be valid for salts, amides, and correspond-

ing acylated nitriles. In connection with the rule,

Hudson mentioned that, “the sugar benzylphenylhy-

Leuckart-Wallach reaction. Reductive al-

drazones rotate to the left when the asymmetric ␣-

kylation of ammonia or of primary or secondary

carbon atom of the configuration has its hydroxyl to

amines with carbonyl compounds and formic acid or

the right, and vice-versa.”

formamides as reducing agents.

“Levnlite” [Solutia]. TM for sodium alumi-

leuco-compound. See vat dye.

num phosphate.

Grade: Regular and high calcium powder.

leucothol B.

Use: Imparts volume, lightness, tenderness, tolerance

CAS: 38302-26-0. mf: C

in use, and good crumb resiliency to cake products.

Hazard: A poison.

Source: Natural product.

levocabastine hydrochloride.

CAS: 79547-78-7. mf: C

•ClH.

leucovorin. Preferred name for folinic acid.

Hazard: Moderately toxic by ingestion.

“Leukanol” [Rohm & Haas]. TM for syn-

levo form. An optical isomer that produces levo-

thetic tanning assistants of the sulfonic type supplied

rotation in a beam of plane polarized light.

in liquid and solid grades. Powerful dispersants for

See levorotatory.

vegetable tannins, and bleaches for chrome-tanned

leather.

levorotatory. Having the property when in solu-

tion of rotating the plane of polarized light to the left

leukocyte. A white blood cell.

or counterclockwise. Levorotatory compounds may

have the prefix l- to distinguish them from their

leukotriene. One of a group of physiologically

dextrorotatory or d- isomers, but the minus sign (−)

active compounds derived directly from arachidonic

is preferred.

acid. They are chemically related to the prostaglan-

dins and occur in white blood cells (leukocytes).

They cause muscle contractions that constrict air

levulinic acid. (␥-ketovaleric acid; acetylpro-

passages in the lungs and are involved in asthma.

pionic acid; 4-oxopentanoic acid; levulic acid).

CAS: 123-76-2. CH

CO(CH

)

COOH.

Properties: Crystals. Bp 245–246C, mp 33–35C, d

leutenizing hormone-releasing factor (pig),

1.1447 (25/4C), refr index 1.442 (16C). Miscible

6-d-leucine-9-(n-ethyl-l-prolinamide)-10-

with water, alcohol, esters, ethers, ketones, aromatic

deglycinamide-, monoacetate (salt).

hydrocarbons; insoluble in aliphatic hydrocarbons.

CAS: 74381-53-6. mf: C

•C

Combustible.

Hazard: A poison.

Use: Intermediate for plasticizers, solvents, resins,

flavors, pharmaceuticals, acidulant and preserva-

leveling. (1) A term used in the paint industry to

tive; chrome plating; solder flux; stabilizer for calci-

describe the application properties of a paint, i.e., its

um greases; control of lime deposits.

ability to cover a dry surface easily and to hold its

level without sagging or running. (2) The ability of a

levulose. See fructose.

nickel-plated coating to cover surface irregularities

of the substrate, achieved by the incorporation of

one or more brighteners in the plating formulation.

Lewis acid. Any molecule or ion (called an elec-

(3) Aiding the uniform dispersion of a dye in a dye

trophile) that can combine with another molecule or

bath or solution by addition of a suitable material,

ion by forming a covalent bond with two electrons

e.g., lignin.

from the second molecule or ion. An acid is thus an

electron acceptor. Hydrogen ion (proton) is the sim-

“Levelume” [ATOTECH]. TM for bright plest substance that will do this, but many com-

high-leveling nickel process. Prepared from nickel pounds such as boron trifluoride, BF

, and alumi-

sulfate, nickel chloride, boric acid, and organic addi- num chloride, AlCl

, exhibit the same behavior and

tion agents. are therefore properly called acids. Such substances

754LEWIS BASE

show acid effects on indicator colors and when dis- ent temperature, obtained from naturally occurring

solved in the proper solvents. triglycerides.

Use: Chemical intermediate, paint and varnishes, al-

kyd resins and soaps.

Lewis base. A substance that forms a covalent

bond by donating a pair of electrons, neutralization

Li. Symbol for lithium.

resulting from reaction between the base and the

acid with formation of a coordinate covalent bond. It

Libby, Willard F. (1908–1980). An American

is also called a nucleophile.

chemist who won the Nobel Prize for chemistry in

See Lewis electron theory.

1960 and in 1980. His first Nobel work involved

radiochemistry and isotope tracer work in the space

Lewis electron theory. A theory involving

program. He is known for the “atomic time clock”

acid and base formation, neutralization, and related

which is a way of estimating the age of ancient

phenomena on the basis of exchange of electrons

materials by measuring the amount of radioactive

between substances and the formation of coordinate

C in organic or carbon-containing objects. His

bonds. It represented an important advance in chem-

Doctorate was awarded at Wesleyan University. He

ical theory, largely replacing earlier concepts. Ad-

also worked at Syracuse, Carnegie Institute of Tech-

vanced in 1923 by Gilbert N. Lewis, it contributed

nology, and Georgetown institutions, among others.

much to the development of coordination chemistry

in which the base is represented by the ligand and the

library. Biology: An unordered collection of

acid by the metal ion.

clones (i.e., cloned DNA from a particular organ-

ism), whose relationship to each other can be estab-

Lewis, Gilbert N. (1875–1946). An American

lished by physical mapping.

chemist, native of Massachusetts, professor of

See genomic library.

chemistry at MIT from 1905 to 1912 after which he

became dean of chemistry at University of Califor-

“Librium” Hydrochloride [Hoffmann-La

nia at Berkeley. His most creative contribution was

Roche]. TM for chlordiazepoxide hydrochlo-

the electron-pair theory of acids and bases which

ride. Manufacture and use restricted.

laid the groundwork for coordination chemistry. He

was also a leading authority on thermodynamics.

“Lica” [Kenrich]. TM for a prefix for a series of

neoalkoxy zirconates.

lewisite. Legal label name for ␤-chlorovinyl-di-

chloroarsine.

licanic acid. (4-keto-9,11,13-octadecatrienoic

acid). CH

(CH

)

(CH:CH)

(CH

)

COCH

COOH.

Lewis metal. Alloy of one part tin and one part

Properties: White crystals. ␣-licanic acid (naturally

bismuth.

occurring isomer) melts at 74–75C, readily isomer-

Properties: Expands when cooling. Mp 138C.

izes to the ␤-form, mp 99.5C. Soluble in organic

Use: Sealing and holding die parts.

solvents.

Derivation: Occurs in oiticica and other oils as glyc-

“Lewisol” 28 [Aqualon]. TM for a pale, hard

erides.

resin, a maleic-modified glycerol ester of rosin.

Acid number 36, softening point 141C, USDA color

lichenic acid. See fumaric acid.

WG.

licorice. See glycyrrhizin.

Lewis, Warren P. (1882–1974). Born in Lau-

rel, Maryland, graduated from MIT in 1905, Ph.D.

lidocaine. (␣-diethylaminoaceto-2,6-xylidide).

from University of Breslau, Germany in 1908. He

CAS: 137-58-6. C

(CH

)

NHCOCH

N(C

)

became professor of chemical engineering at MIT in

Properties: White or slightly yellow crystalline

1910. He is often regarded as the father of chemical

powder; characteristic odor. Mp 66–69C, bp

engineering in the U.S., as his outstanding books

180–182C (at 4 mm Hg). Soluble in alcohol, ether,

and other publications did much to establish the

or chloroform; insoluble in water.

fundamental principles of this field.

Derivation: By action of diethylamine on chloroace-

tylxylidide.

Leyden temperature scale. A low-tempera-

Grade: USP.

ture thermometer scale based on a boiling point of

Use: Medicine (local anesthetic).

hydrogen equal to −252.74°C and of oxygen equal

to −182.95°C.

Lieben iodoform reaction. Cleavage of

methyl ketones with halogens (mostly iodine) and

base to carboxylic acids and haloform.

“L-310 Fatty Acid” [Procter & Gamble].

TM for a fatty acid derived from linseed oil.

Properties: The major component acids are oleic,

Liebig, Justus von. (1803–1873). A German

linoleic, and linolenic. Light yellow liquid at ambi- chemist who founded the Annalen, a world-famous

755 LIGNIN SULFONATE

chemical journal. He was a great teacher of chemis-

light hydrocarbon. One of a group of hydro-

try, training such men as Hoffmann, who did basic carbon products derived from natural gas or petrole-

work on organic dyes. Liebig contributed original um; ethane, propane, iso- and normal butane, and

research in the fields of human physiology, plant natural gasoline (C

and heavier). Produced largely

life, soil chemistry, and was the discoverer of chlo- in southwest Texas and Louisiana, these are used as

roform, chloral, and cyanogen compounds. He was feedstocks for a wide vareity of organics.

the first to recommend addition of nutrients to soils See liquefied petroleum gas.

and thus may be considered the originator of the

fertilizer industry.

“Light-Lead” [Reactor]. TM for lead-lined

polyethylene shielding bricks. Weight of one brick

is 7 pounds.

life, origin. (biogenesis). The succession of

chemical events that led up to the appearance of

light metal. In engineering terminology, a metal

living organisms on earth about 3.3 billion years

of specific gravity less than three that is strong

ago. According to one theory, substantiated by ex-

enough for construction use (aluminum, magne-

perimental evidence, this occurred as follows. The

sium, beryllium).

inorganic compounds originally present were car-

bides, water, ammonia, and carbon dioxide. The

light microscope. See optical microscope.

carbides reacted with water to form methane, which

in turn reacted with ammonia and water vapor as a

light oil. (coal tar light oil). A fractional distil-

result of an electric impulse to form amino acids,

late from coal tar with bp range from 110–210C,

porphyrins, and nucleotides (or their precursors).

consisting of a mixture of benzene, pyridine, tolu-

All these compounds have been created artificially

ene, phenol, and cresols. The term is also sometimes

in the laboratory. It has further been shown that

used for oils of about the same bp range, but from

amino acids and nucleotides can be concentrated

other sources.

into proteins (and probably nucleic acids) by the

Grade: Technical.

action of zinc-bearing clays, which were present

Hazard: Highly flammable, dangerous fire risk.

along the shores of the primeval oceans. Little or no

Use: Source of benzene, solvent naphthas, toluene,

free oxygen existed in the primordial atmosphere,

phenol, and cresols.

that consisted chiefly of reducing gases. The com-

plex chemical reactions which eventually resulted in

light reactions. The reactions of photosynthesis

the formation of DNA took place in an anaerobic

occuring only in the light.

aqueous environment, and the earliest living organ-

isms developed in a nutrient solution in which free

light water. (1) A fire-fighting agent consisting

oxygen finally appeared as the result of photosyn-

of a water solution of perfluorocarbon compounds

thesis by blue-green bacteria. Another theory ad-

mixed with a water-soluble thickener of the polyox-

vances the idea that essential life chemicals such as

yethylene compound type. It can be used simulta-

purines and amino acids were formed under primi-

neously with a dry chemical to smother gasoline or

tive conditions from aqueous solutions of hydrogen

similar fires. (2) Ordinary water (as distinct from

cyanide.

heavy water) used to both cool and moderate nuclear

reactors.

ligand. A molecule, ion, or atom that is attached to

the central atom of a coordination compound, a

lignaloe oil. See bois de rose oil.

chelate, or other complex. Thus, the ammonia mole-

cules in [Co(NH3)

]

and the chlorine atoms in

lignin. A phenylpropane polymer of amorphous

[PtCl

]

2−

are ligands. Ligands are also called com-

structure comprising 17–30% wood. It is so closely

plexing agents, e.g., EDTA, ammonia, etc.

associated with the holocellulose which makes up

See chelate; coordination compound.

the balance of woody material that it can be sepa-

rated from it only by chemical reaction at high tem-

perature. It is believed to function as a plastic binder

ligase. An enzyme, T4 DNA ligase, which can

for the holocellulose fibers. It is recovered from

link pieces of DNA together. The pieces must have

wood-processing wastes in limited amounts.

compatible ends (both of them blunt, or else mutual-

Use: Stabilization of asphalt emulsions, ceramic

ly compatible sticky ends), and the ligation reaction

binder and deflocculant, dye leveler and dispersant,

requires ATP.

drilling-fluid additive, precipitation of proteins, ex-

tender for phenolic plastics, special molded prod-

ucts, source of vanillin, phenol, and of a component

ligation. The process of splicing two pieces of

of battery expanders.

DNA together. In practice, a pool of DNA fragments

are treated with ligase (see “ligase”) in the presence

of ATP, and all possible splicing products are pro-

lignin sulfonate. (lignosulfonate). A metallic

duced, including circularized forms and end-to-end sulfonate salt made from the lignin of sulfite pulp-

ligation of 2, 3 or more pieces. mill liquors, mw range 1000–20,000.

756LIGNITE

Properties: Light-tan to dark-brown powder; no pro-

lime, agricultural. Lime slaked with a mini-

mum amount of water to form calcium hydroxide.

nounced odor. Stable in dry form and relatively

stable in aqueous solution. Nonhygroscopic, no def-

inite mp, decomposes above 200C, d about 1.5.

lime, air-slaked. Lime which has absorbed car-

Forms colloidal solutions or dispersions in water;

bon dioxide and moisture from the atmosphere. It

practically insoluble in all organic solvents.

consists of a powder composed of calcium carbonate

Use: Dispersing agent in concrete and carbon

and calcium hydroxide.

black−rubber mixes, extender for tanning agents,

oil-well drilling mud additives, ore flotation agents,

lime, chlorinated. (chloride of lime; bleach-

production of vanillin, industrial cleaners, gypsum

ing powder). CaCl(ClO)•4H

slurried, dyestuffs, pesticide formulations. Com-

Properties: White powder; chlorine odor. Mp (de-

mercially available as the salts of most metals and of

composes). Decomposes in water, acids.

ammonium.

Derivation: By conducting chlorine into a boxlike

See “Raykrome” [Rayonier].

structure containing slaked lime spread upon perfo-

rated shelves.

Grade: 35–37% active chlorine, technical.

lignite. (brown coal). A low rank of coal be-

Hazard: Evolves chlorine and, at higher tempera-

tween peat and subbituminous; it contains 35–40%

tures oxygen. With acids or moisture evolves chlo-

water. It occurs in the continental U.S., Alaska,

rine freely at ordinary temperatures.

Germany and the Netherlands. Its Btu value is low.

Use: Textile and other bleaching applications, organ-

Drying, crushing, and pelletizing lignite with an

ic synthesis, deodorizer, disinfectant.

asphaltic binder for direct use as fuel has been suc-

See calcium hypochlorite; bleach.

cessfully demonstrated. Polymer resins (polyesters

and polyamides) can be derived from lignite by

lime citrate. See calcium citrate.

oxidation with nitric acid, followed by extraction of

the nitrocoal acids, which are the basis of the poly-

lime, fat. A pure lime that combines readily with

mer molecules. Peat can also be used. A process for

water to form a fine, white powder, free from grit,

gasification of lignite to produce methanol alcohol is

and makes a smooth, stiff paste with excess of water.

approaching commercial development in Sweden.

Must not be loaded hot.

See peat; gasification.

See lime, lean.

lignoceric acid. (n-tetracosanoic acid).

lime, hydrated. See calcium hydroxide.

(CH

)

COOH. A long-chain saturated fatty acid

found in minor quantities in most natural fats.

lime, hydraulic. A variety of calcined lime-

Properties: Crystals. Mp 84.2C, bp 272C (10 mm

stone that when pulverized absorbs water without

Hg), d 0.8207, refr index 1.4287 (100C). Nearly

swelling or heating and gives a cement that hardens

insoluble in ethanol.

under water. The limestone burned for this purpose

Source: Lignite and beechwood tar, peanut oil,

usually contains 10–17% silica, alumina, and iron,

sphingomyelin.

and 40–45% lime, magnesia sometimes replacing

Grade: Technical, 99%.

lime. Must not be loaded hot.

Use: Biochemical research.

lime hypophosphite. See calcium hypophos-

lignosulfonate. See lignin sulfonate.

phite.

ligroin. A saturated volatile fraction of petroleum

lime, lean. A lime which does not lake freely

boiling in the range 60–110C. There is a special

with water because it has been prepared from lime-

grade of ligroin known as petroleum benzin.

stone containing a high percentage of impurities,

Hazard: Highly flammable, dangerous fire risk.

e.g., silica, iron, alumina, etc. Must not be loaded

Toxic by ingestion and inhalation.

hot.

Use: Solvent for resins, paints, varnishes, etc.

lime-nitrogen. See calcium cyanamide.

lime. Specifically, calcium oxide (CaO); more

generally, any of the various chemical and physical

lime oil, distilled.

forms of quicklime, hydrated lime, and hydraulic

CAS: 8008-26-2. Colorless to greenish-yellow, vol-

lime (adapted from ASTM definition C41-47). Non-

atile oil obtained by distillation from the juice or

combustible.

whole crushed fruit of Citrus aurantifolia Swingle.

Hazard: Unslaked lime (quicklime) yields heat on

Properties: Refr index 1.4745–1.4770 (20C), d

mixing with water and is a caustic irritant.

0.855–0.863 (25C), angular rotation +34 to +47

Use: See calcium oxide, calcium hydroxide.

degrees. Soluble in most fixed oils and mineral oil;

See calcium oxide.

insoluble in glycerol and propylene glycol. Com-

bustible.

lime acetate. See calcium acetate. Chief constituents: Terpineol, citral.

757 LINALYL ACETATE

Grade: FCC (contains between 0.5 and 2.5% of alde-

limonene.

hydes, calculated as citral). CAS: 138-86-3. C

. A widely distributed, opti-

Use: Extracts, flavoring, perfumery, toilet soaps, cos- cally active terpene, closely related to isoprene. It

metics.

occurs naturally in both d- and l-forms. The racemic

mixture of the two isomers is known as dipentene.

lime oil, expressed. See citrus peel oil.

lime saltpeter. See calcium nitrate.

lime, slaked. See calcium hydroxide.

limestone.

CAS: 1317-65-3. CaCO

. A noncombustible solid

characteristic of sedimentary rocks and composed

Properties: Colorless liquid. (1) D 0.8411 (20C), bp

mainly of calcium carbonate in the form of the min-

176–176.4C; (2) d 0.8422 (20C), bp 176–176.4C.

eral calcite, Mohs hardness about 3. Limestones are

Oxidizes to a film in air, oxidation behavior similar

sometimes classed according to the impurities con-

to that of rubber or drying oils.

tained. For example, dolomitic limestone: usually a

Derivation: (1) Lemon, bergamot, caraway, orange,

limestone containing more than 5% magnesium car-

and other oils, (2) peppermint and spearmint oils.

bonate; magnesium limestone: dolomitic limestone,

Use: Flavoring, fragrance and perfume materials,

used as a solid diluent and carrier in pesticides;

solvent, wetting agent, resin manufacture.

argillaceous limestone: contains clays, used in ce-

ment manufacture as “cement rock”; siliceous lime-

limonene dioxide. See dipentene dioxide.

stone: a limestone containing sand or quartz. Lime-

stones are also named according to the formation in

limonene, inactive. (or racemic or dl).

which they occur.

See dipentene.

See marble; dolomite.

Use: Building stone, metallurgy (flux), manufacture

limonene monoxide. See dipentene mon-

of lime, source of carbon dioxide, agriculture, road

oxide.

ballast, cement (Portland and natural), alkali manu-

facture, removal of sulfur dioxide from stack gases

linalool. (linalol; 3,7-dimethyl-1,6-octadien-3-

and sulfur from coal.

ol).

CAS: 78-70-6.

(CH

)

C:CHCH

C(CH