G
. See gamma. gadodiamide hydrate.
CAS: 122795-43-1. mf: C
16
H
28
GdN
5
O
9
xH
2
O.
Hazard: Low toxicity. A reproductive hazard.
G. See guanine
g. (1) Abbreviation of gram, (2) acceleration due to
gadolinium.
gravity.
CAS: 7440-54-2. Gd. A rare-earth element of the
lanthanide series, atomic number 64, group IIIB of
g. Abbreviation of microgram. the periodic table, aw 157.25, valence of 3; seven
natural isotopes.
Properties: Lustrous metal. D 7.87, mp 1312C, bp
“G-30” [Haynes]. TM for a high-strength,
3000C; reacts slowly with water. Soluble in dilute
nickel-based alloy with outstanding corrosion resis-
acid; insoluble in water. Exhibits a high degree of
tance to strong oxidizing media, and excellent resis-
magnetism, especially at low temperatures; salts are
tance to localized corrosion and stress corrosion
colorless; has highest neutron absorption cross-sec-
cracking while maintaining ease of welding and
tion of any known element; has superconductive
fabrication.
properties, burns in air to form the oxide. Combus-
Available forms: Sheet, plate, bars, rods, welding
tible.
electrodes, and wire.
Derivation: (1) Reduction of the fluoride with calci-
Use: Fabrication into all types of process equipment.
um, (2) electrolysis of the chloride with sodium
chloride or potassium chloride in an iron pot that
“G-942” [Du Pont]. TM for an aqueous solu-
serves as an anode and graphite cathode.
tion of the partial sodium salt of a polymeric carbox-
Grade: Ingots, lumps, turnings, powder up to
ylic acid.
99.9+% pure.
Use: Tanning agent.
Use: Neutron shielding, garnets in microwave filters,
phosphor activator, catalyst, scavenger for oxygen
Ga. Symbol for gallium.
in titanium production.
GABA. Abbreviation for -aminobutyric acid.
gadolinium chloride. GdCl
3
xH
2
O. Colorless
See aminobutyric acid.
crystals, soluble in water, purities up to 99.9%.
Use: Gadolinium sponge metal, by contact with a
Gabriel-Colman rearrangement. Forma-
reducing metal vapor; source of gadolinium.
tion of isoquinoline derivatives by the action of
sodium ethoxide on phthalimidoacetic esters.
gadolinium fluoride. GdF
3
2H
2
O. Available
up to 99.9% purity.
Gabriel ethylenimine method. Formation
Properties: Semisolid mass.
of ethylenimines (aziridines) by elimination of hy-
Hazard: Toxic material. TLV: 2.5 mg(F)/m
3
.
drogen halides from aliphatic vicinal haloamines
Use: Source of gadolinium.
with alkali. The method can be extended to the
preparation of five- and six-membered ring amines.
gadolinium nitrate. Gd(NO
3
)
3
xH
2
O. Color-
less crystals, soluble in water, decomposes at 110C,
Gabriel synthesis. Conversion of alkyl halides
purities up to 99.9% gadolinium salt.
to primary amines by treatment with potassium
Hazard: Fire risk in contact with organic materials.
phthalimide and hydrolysis of the N-alkylphthali-
mides formed.
gadolinium oxalate. Gd
2
(C
2
O
4
)
3
10H
2
O.
G acid. (2-naphthol-6,8-disulfonic acid).
Properties: White powder. Insoluble in water;
slightly soluble in acids; loses 6H
2
O at 110C.
Available forms: Purities up to 99.9% gadolinium
salt.
gadolinium oxide. Gd
2
O
3
. Properties: White- to
cream-colored powder, d 7.41, mp 2330C, insoluble
in water, soluble in acids to form the corresponding
Properties: White needles. Soluble in water. salts, hygroscopic, absorbs carbon dioxide from the
Derivation: Sulfonation of -naphthol. air, purities up to 99.8% gadolinium oxide.
See Schaeffer acid. Derivation: Calcination of gadolinium salts, liquid/
Use: Azo dye intermediate. liquid ion-exchange separation.
592
593 GALLIUM ARSENIDE
Use: Neutron shields; catalysts; dielectric ceramics; metallic luster, good cubic cleavage. D 7.4–7.6,
Mohs hardness 2.5. Soluble in strong nitric acid, in
filament coatings; special glasses; TV phosphor ac-
excess of hot hydrochloric acid.
tivator; lasers, masers, and telecommunication; lab-
Occurrence: Western U.S., Canada, Africa, South
oratory reagent.
America.
Use: Chief ore of lead, frequently recovered for the
gadolinium sulfate. Gd
2
(SO
4
)
3
8H
2
O.
silver it sometimes contains.
Properties: Colorless crystals. D 3.01 (15C), purities
up to 99.9% gadolinium salt. Slightly soluble in hot
water; more soluble in coldwater.
“Galex” [Natrochem]. TM for dispropor-
Use: Cryogenic research; the selenide is used in ther-
tioned gum rosin or wood rosin.
moelectric generating devices.
Properties: Stable. Softening point 64–72C, acid no.
150170 degrees.
gafamide coa. See coconut amine oil con-
Use: Adhesives, extender in rubber formulations.
densate.
gallic acid. (3,4,5-trihydroxybenzoic acid).
“GAF” Carbonyl Iron Powders
CAS: 149-91-7. C
6
H
2
(OH)
3
CO
2
H.
[International Specialty]. TM for micro-
scopic spheres of extremely pure iron. Produced in
11 carefully controlled grades ranging in particle
size from 3 to 20 microns in diameter. The iron
content of some types is as high as 99.5%.
Use: High-frequency cores for radio, telephone, tele-
vision, short-wave transmitters, radar receivers, di-
rection finders; alloying agents; catalysts; powder
metallurgy; magnetic fluids.
Properties: Colorless or slightly yellow crystalline
needles or prisms. D 1.694, mp 222–240C. Soluble
Gal. Abbreviation for galactose.
in alcohol and glycerol; sparingly soluble in water
and ether.
d-galactosamine hydrochloride. (2-amino-
Derivation: Action of mold on solutions of tannin or
2-dioxy-d-galactose).
by boiling the latter with strong acid or caustic soda.
CAS: 1772-03-8. C
6
H
14
ClNO
5
.
Use: Photography, writing ink, dyeing, manufacture
Properties: Crystalline solid. Mw 215.64, mp
of pyrogallol, tanning agent and manufacture of
182185C (decomposes).
tannins, paper manufacture, pharmaceuticals, en-
Derivation: Amino sugar isolated from chondroitin
graving and lithography, analytical reagent.
sulfate.
gallium.
galactose.
CAS: 7440-55-3. Ga. Metallic element of atomic
CAS: 59-23-4. C
6
H
12
O
6
. A monosaccharide com-
number 31, group IIIA of the periodic table, aw
monly occurring in milk sugar or lactose.
69.72, valences of 2, 3; two stable isotopes.
Properties: White crystals. Mp 165–168C. Soluble
Properties: Silvery-white liquid at room tempera-
in hot water and pyridine; slightly soluble in glyc-
ture. Mp 29.7C, bp 2403C,; may be undercooled to
erol.
almost 0C without solidifying, d 5.9 (25C). More
Derivation: By acid hydrolysis of lactose.
dense as a liquid than as a solid. Soluble in acid,
Use: Organic synthesis, medicine (diagnostic aid).
alkali; slightly soluble in mercury. Reacts with most
metals at high temperatures.
-galactosidase.
Grade: Up to 99.9999% purity.
Properties: Derived from Mortierella vinaceae var.
Occurrence: Prepared commercially from zinc ores
raffinoseutilizer.
and bauxite.
Use: Food additive.
Derivation: Extraction of gallium as gallium chlo-
ride by ethyl ether or isopropyl ether and subsequent
D(+)-galacturonic acid. COOH(CH
2
O)
4
CHO.
electrodeposition from an alkaline gallium oxide
A major constituent of plant pectins. It exhibits mu-
solution.
tarotation, having both an and a form.
Use: The metal has no significant commercial uses.
Properties: The form melts with decomposition at
Its compounds are used as semiconductors.
159–160C. Soluble in water, slightly soluble in hot
alcohol; insoluble in ether.
gallium antimonide. GaSb. Available in an
Derivation: Hydrolysis of pectins.
electronic grade.
Use: Biochemical research.
Use: Semiconducting devices.
galena. (galenite; lead glance).
CAS: 1314-87-0. PbS. Natural lead sulfide.
gallium arsenide.
Properties: Lead gray in color, lead-gray streak, CAS: 1303-00-0. GaAs.
594GALLIUM OXIDES
Properties: Crystals. Mp 1238C. Electrolumines-
galvanizing. Coating of a ferrous metal by pass-
cent in infrared light.
ing it through a bath of molten zinc or by electrode-
Grade: Ingots, polycrystalline form in high-purity
position of zinc. In the former process, the iron and
electronic grade, single crystals. Often alloyed with
zinc combine to form an intermetallic compound at
gallium phosphide or indium arsenide.
the interface, the outer surface being relatively pure
Hazard: Toxic metal.
zinc, which crystallizes as it cools to form the char-
Use: Semiconductor in light-emitting diodes for tele-
acteristic spangle. The electrodeposition method
phone dials, injection lasers, solar cells, magnetore-
gives a uniform surface that may be either dull or
sistance devices, thermistors, microwave genera-
bright. Duration of corrosion protection is directly
tion.
related to the thickness of the zinc coating.
See arsenic.
See sacrificial protection.
“Galvoline” [Dow]. TM for a cored magne-
gallium oxides. The sesquioxide, Ga
2
O
3
, and
sium ribbon used as a continuous anode for the
suboxide, Ga
2
O, are known. Both are stable at ordi-
cathode protection of buried pipelines and other
nary temperatures.
metal structures. Combustible.
See gallium sesquioxide.
“Galvomag” [Dow]. TM for magnesium alloy
gallium phosphide. GaP.
composition used in anodes in cathodic protection.
Properties: Pale-orange, transparent crystals or
whiskers up to 2 cm long, made by vapor phase
“Galvorod” [Dow]. TM for a cored magne-
reaction at relatively low temperatures between
sium rod used as an anode in the cathodic protection
phosphorus and gallium suboxide. These crystals
of water-heater tanks. Combustible.
are intermediate between normal semiconductors
and insulators or phosphors. They operate over a
gamete. A sex cell (egg or sperm) that carries half
temperature range of 55 to 500C. Gallium phos-
the normal complement of chromosomes and com-
phide is electroluminescent in visible light.
bines with another sex cell to produce a new individ-
Grade: Polycrystalline form in high-purity electron-
ual possessing the normal complement.
ic grade, single crystals, whiskers.
Use: Semiconducting devices.
gametes. Reproductive cells (sperm or egg)
which are haploid.
gallium sesquioxide. Ga
2
O
3
.
Properties: ( form) White crystals. D 6.44, mp
gametocide. A substance that can control polli-
1900C, changes to form at 600C. ( form) white
nation of plants by selectively killing plant sex cells
crystals. D 5.88. Both forms are insoluble in hot
(gametes). Some suggested gametocides are maleic
acid.
hydrazide and sodium-,-dichloroisobutyrate.
Grade: High-purity electronic.
Use: Spectroscopic analysis.
gametophyte. The haploid stage in the life cycle
of an organism undergoing alternations of genera-
gallocyanine. (CI 51030). C
15
H
13
ClN
2
O
5
.
tions. The gametophyte is multicellular and mitoti-
Properties: Greenish solid. Insoluble in water; solu-
cally produces gametes. In plants, the gametophyte
ble in alcohol, glacial acetic acid, alkali carbonate,
nourishes the zygote and young sporophyte.
and concentrated hydrochloric acid.
Derivation: Reaction of gallic acid with nitrosodi-
gamma. (). A prefix having meanings analo-
methylaniline.
gous to those of , namely, to designate locations of
Use: Analytical reagent for lead, dye, and biological
substituents in a compound or a particular form or
stain.
modification of an organic substance (-globulin) or
a metal crystal. It also identifies the most intense
gallotannic acid. See tannic acid.
form of short-wave radiation.
See gamma ray.
galls. (nutgalls). Excrescences on various kinds
of oak trees resulting from the deposition of insect
gamma-acid. See -acid.
eggs.
Grade: The best grades (55–60% tannic acid) come
gamma globulin. globulin.
from Iran, Syria, Turkey, and Tripoli.
See globulin.
Use: Source of gallic and gallotanic acids, leather
tanning, writing inks, medicine, textile printing,
gamma ray. (). Electromagnetic radiation of
pharmaceuticals.
extremely short wavelength and intensely high ener-
gy. rays originate in the atomic nucleus; they
“Galvan” [Cabot]. TM for battery and electri- usually accompany and emission, as in the decay
cally conductive carbon black. of radium, and always accompany fission. rays are
595 GAS BLACK
extremely penetrating and are absorbed by dense
gardenia yellow.
materials like lead and depleted uranium. CAS: 94238-00-3.
Hazard: Exposure to radiation may be lethal. Com- Hazard: Moderately toxic by ingestion.
plete protection is essential. Source: Natural product.
Use: To initiate chemical syntheses (ethyl bromide)
and cross-linking of polyethylene and other poly-
gardrin. See enprostil.
mers; biochemical research; food preservation; ana-
lytical chemistry.
garlic oil.
See X ray; radiation.
CAS: 8000-78-0.
Hazard: Moderately toxic by ingestion.
gamma-ray spectroscopy. (-ray spectros-
Source: Natural product.
copy). An analytical technique involving the use of
radiation, which is emitted from radioactive nuclei
“Garlon” [Dow]. TM for herbicides containing
in discrete energies. The spectrum of energies and
water-soluble salts or oil-soluble esters of 3,5,6-tri-
the relative intensities of the rays often character-
chloro-2-pyridyloxyacetic acid.
ize the radionuclide that emits them; these are deter-
mined by -ray spectroscopy. It is possible to identi-
garnet, natural. A group of silicate minerals.
fy quantitatively the elements present by their
Garnets in nature are usually composed of a mix of
characteristic -ray spectra, as well as to determine
various garnet subspecies.
radioactive decay rates.
Use: Abrasive, blast cleaning of buildings.
“Ganex” [International Specialty]. TM for
garnet, synthetic. Single-crystal garnets de-
a series of modified polyvinylpyrrolidone-based
signed, by the introduction of bismuth, calcium, and
products. Available in a wide range of physical
vanadium, for microwave devices such as low-fre-
forms, from liquid to waxy solid to granular solid.
quency ferrimagnetic resonators. Special yttrium,
Used as emollients and lubricity additives, dispers-
iron, and aluminum garnets are used in lasers and
ing and suspending agents, pour-point depressants,
electronic devices.
sizing additives.
garnierite. (Ni, Mg)
6
(OH)
6
Si
4
O
11
H
2
O. A natural
ganglefene.
nickel-magnesium silicate, occurring as a natural
CAS: 299-61-6. mf: C
20
H
33
NO
3
.
alteration of magnesium silicate rocks. A nickel ore.
Hazard: Moderately toxic.
gas. (). A state of matter characterized by very
gangliosides. Sphingolipids containing complex
low density and viscosity (relative to liquids and
oligosaccharides as head groups.
solids), comparatively great expansion and contrac-
tion with changes in pressure and temperature, abili-
gangue. The minerals and rock mined with a
ty to diffuse readily into other gases, and ability to
metallic ore but valueless in themselves or used only
occupy with almost complete uniformity the whole
as a by-product. They are separated from the ore in
of any container. Gases may be either elements (ar-
the milling and extraction processes, often as slag.
gon) or compounds (carbon dioxide); elemental
Common gangue materials are quartz, calcite, li-
gases may be monatomic (helium), diatomic (chlo-
monite, feldspar, pyrite, etc.
rine), or triatomic (ozone). All exist in the gaseous
state at standard temperature and pressure but can be
“Gantrez” AN [International Specialty].
liquefied by pressure. The most abundant gases on
TM for an interpolymer of methyl vinyl ether and
earth are oxygen, hydrogen, nitrogen (diatomic),
maleic anhydride.
and carbon dioxide. Gases are used for fundamental
Properties: Soluble in water and many organic sol-
research on the behavior of matter largely because
vents. Compatible with a wide range of gums, res-
the low concentration permits isolation of the phe-
ins, and plasticizers and with most metallic salts.
nomena far better than is possible in liquids or sol-
Stable in acid and alkaline solutions. Available in a
ids. A “perfect” or ideal gas closely conforms to the
range of molecular weights.
simple gas laws (Boyle’s law, Charles’ law) for
Use: Ammonium nitrate slurry explosives, for its
expansion and contraction. Note: Use of the word
suspending action and cross-linking ability; rust-
gas for gasoline, natural gas, or the anesthetic ni-
preventive films; antistatic and finishing agent in
trous oxide is acceptable only in informal communi-
natural and synthetic textiles and glass fibers; adhe-
cation.
sives and coatings; thickening agent and protective
See kinetic theory; compressed gas; noxious gas;
colloid; flocculant and foam stabilizer in papermak-
noble gas; vapor.
ing; photoreproduction; pharmaceutical prepara-
tions; cosmetics; etc.
gas, asphyxiant. See asphyxiant gas.
“Gantrez” M [International Specialty].
TM for polyvinyl methyl ether. gas black. See carbon black.
596GAS CHROMATOGRAPHY
gas chromatography. (GC; gas-liquid chro- hydrogen to form methane (hydrogasification); (2)
matography; GLC; vapor-phase chromatography; by reacting steam with hot coal (800C) in the pres-
VPC). The process in which the components of a ence of air or oxygen to form carbon monoxide and
hydrogen (synthesis gas), followed by a methana-
mix are separated from one another by volatilizing
tion reaction (Fischer-Tropsch method); (3) by un-
the sample into a carrier gas stream that is passing
derground aeration. In methods (1) and (2), the coal
through and over a bed of packing consisting of a
enters the reaction sequence in finely divided form;
20–200 mesh solid support. The surface of the latter
hydrocarbon gases, naphtha, and fuel oils of various
is usually coated with a relatively nonvolatile liquid
grades can be produced by several modifications. In
(the stationary phase). This gives rise to the term
method (3), air is pumped down to previously ignit-
gas-liquid chromatography. If the liquid is not
ed coal seams and the combustible products evolved
present, the process is gas-solid chromatography,
are collected. Many variations of methods (1) and
which is also widely used for analysis. Different
(2) have been researched in the U.S., but none is
components move through the bed of packing at
economically competitive with crude oil. Several
different rates and so appear separately, at the ef-
have advanced to the pilot stage, and projections of
fluent end, where they are detected and measured by
cost, investment, and installation for large-scale op-
thermal conductivity changes, density differences,
eration have been made. Environmental and geo-
or ionization detectors. Gas chromatography is ad-
graphic considerations have also been investigated.
vantageous as a means of analysis of minute quanti-
The controlling factor for future development is the
ties of complex mixtures from industrial, biological,
price of crude. All three methods mentioned are
and chemical sources and is also of potential value in
technically feasible. During World War II hydrocar-
actually preparing moderate quantities of highly pu-
bon fuels were produced from coal on a large scale in
rified compounds otherwise difficult to separate
Germany by both hydrogasification and Fischer-
from the mixture in which they occur.
Tropsch methods. Large-scale coal conversion has
been successfully achieved by the Lurgi and Sasol
gas, compressed. See compressed gas; lique-
methods; the latter, in South Africa, is a large-scale
fied petroleum gas.
installation utilizing the Fischer-Tropsch technolo-
gy. The Lurgi technique is in production at a number
gas constant (R). Pressure times volume divid-
of locations. Catalytic gasification of peat for pro-
ed by the temperature of one gram-molecule of any
duction of methanol is now utilized on a commercial
ideal gas in the general gas law.
scale; use of lignite and wood for this purpose is
p
0
v
0
under development.
R
=
273C
See Fischer-Tropsch process; synthesis gas.
gas, inert. See noble gas, inert.
gas constant, molar. R in general gas law, PV
=
nRT, equal to 0.082060 L-atm mole
1
degree
1
.
gas laws. See Boyle’s law; Charles’ law;
Gay-Lussac’s law; ideal gas.
gaseous diffusion. See diffusion, gaseous.
gas, liquefied petroleum. See liquefied pe-
gas hydrate. A clathrate compound formed by a
troleum gas.
gas (either noble or reactive) and water. The com-
pounds are crystalline solids and are insoluble in
gas liquid. See light hydrocarbon.
water. They usually form (only at relatively low
temperatures and high pressures) directly by contact
gas, natural. See natural gas.
of gas and liquid water. From 6 to 18 molecules of
water may combine with each molecule of gas, de-
gas, noble. See noble.
pending on the nature of the gas. The best-known
gas hydrates are those of ethane, ethylene, propane,
and isobutane. Others include methane and 1-bu-
gasohol Gasoline blended with alcohol. Typically
tene, most of the fluorocarbon refrigerant gases, 10% methanol or ethanol is blended with the gaso-
nitrous oxide, acetylene, vinyl chloride, carbon di- line.
oxide, methyl and ethyl chloride, methyl and ethyl
bromide, cyclopropane, hydrogen sulfide, methyl
gas oil. A liquid petroleum distillate with viscosi-
mercaptan, and sulfur dioxide. Interest in the gas
ty and boiling range between those of kerosene and
hydrates originated mainly because of the nuisance
lubricating oil. Boiling range 232–426C, flash p
of such compound formation in gas pipelines. In
150F (65.5C), autoign temp 640F (337C). Combus-
recent years, propane has been used successfully to
tible.
precipitate water from salt solution (or seawater),
Use: Absorption oil, manufacture of ethylene.
thus yielding potable water.
gasoline.
gasification.
Production of gaseous or liquid hy- CAS: 8006-61-9. A mixture of volatile hydrocar-
drocarbon fuels from coal (1) by direct addition of bons suitable for use in a spark-ignited internal-
597 GAUGE
combustion engine and having an octane number of other chemical conversion processes. Its octane
at least 60. The major components are branched- number is low.
chain paraffins, cycloparaffins, and aromatics. white gasoline. An unleaded gasoline especially de-
There are several methods of production: distillation signed for use in motorboats; it is uncracked and
or fractionation, which yields straight-run product strongly inhibited against oxidation to avoid gum
formation and is usually not colored to distinguish it
of relatively low octane number, used primarily for
from other grades. It also serves as a fuel for camp
blending; thermal and catalytic cracking; reforming;
lanterns and portable stoves.
polymerization; isomerization; and dehydrocyclo-
Hazard: Highly flammable, dangerous fire and ex-
dimerization. All but the first are various means of
plosion risk. TLV: 300 ppm; STEL 500 ppm; animal
converting hydrocarbon gases into motor fuels by
carcinogen.
modifications of chemical structure, usually involv-
ing catalysis. The present commercial source of gas-
gas, perfect. See ideal gas.
oline is petroleum, but it may also be produced from
shale oil and Athabasca tar sands, as well as by
Gastaldi synthesis. Formation of dicyanopyra-
hydrogenation or gasification of coal.
zines by cyclization of two molecules of an amino-
anti-knock gasoline. A gasoline to which a low per-
cyanomethyl ketone, produced by treatment of an
centage of methyl-tert-butyl ether (MBTE) has been
isonitrosomethyl ketone bisulfite compound with
added to eliminate knocking and increase octane
potassium cyanide, heating in hydrochloric acid,
number. This compound has almost completely re-
and oxidation.
placed tetraethyllead. Gasolines of octane number
100 or more are used chiefly as aviation fuel; those
gastric juice. A mixture of hydrochloric acid
having a research octane number of approximately
and pepsin secreted by glands in the stomach in
90 are in general automotive use. See antiknock
response to a conditioned nerve reflex. Its pH is
agent; octane number.
about 2.0. Its action in the metabolic breakdown of
casinghead gasoline. See natural gasoline (below).
food components is essential to the digestive pro-
cracked gasoline. Gasolines produced by the cata-
cess, though carbohydrate decomposition is initiat-
lytic decomposition of high-boiling components of
ed by the saliva.
petroleum. In general, such gasolines have much
See digestion (1).
higher octane ratings (80–100) than that produced
by fractional distillation. The difference is due to the
gastrin tetrapeptide amide.
prevalence of unsaturated, aromatic, and branched-
CAS: 1947-37-1. mf: C
37
H
42
N
6
O
8
S.
chain hydrocarbons in the cracked gasoline. The
Hazard: Moderately toxic by ingestion.
actual properties vary widely with the nature of the
starting material and the temperature, time, pres-
gate. The opening in an injection mold leading
sure, and catalyst used in cracking.
from the sprue or runner to the mold cavity; the term
high-octane gasoline. A gasoline with an octane
also refers to molded material removed from the
number of 90–100. See antiknock gasoline;
aperture when the product is ejected.
octane number.
lead-free gasoline. An automotive fuel containing
Gattermann aldehyde synthesis. Prepara-
no more than 0.05 g lead per gallon, designed for use
tion of aldehydes of phenols, phenol ethers, or het-
in engines equipped with catalytic converters.
erocyclic compounds by treatment of the aromatic
natural gasoline. A gasoline obtained by recovering
substrate with hydrogen cyanide and hydrochloric
the butane, pentane, and hexane hydrocarbons
acid in the presence of Lewis acid catalysts.
present in small proportion in certain natural gases.
Used in blending to produce a finished gasoline with
Gattermann-Koch reaction. Formulation of
adjusted volatility but low octane number. Do not
benzene, alkylbenzenes, or polycyclic aromatic hy-
confuse with natural gas.
drocarbons with carbon monoxide and hydrochloric
polymer gasoline. A gasoline produced by polymer-
acid in the presence of aluminum chloride at high
ization of low molecular weight hydrocarbons such
pressure. Addition of cuprous chloride allows the
as ethylene, propene, and butenes. Used in small
reaction to proceed at atmospheric pressure.
amounts for blending with other gasolines to im-
prove their octane numbers.
pyrolysis gasoline. Gasoline produced by thermal
gauge. An instrument for measuring and indicat-
cracking as a by-product of ethylene manufacture. It ing such process variables as pressure (hydraulic,
is used as a source of benzene by the hydrodealkyla- steam, air), liquid level, thickness, vacuum, etc. The
tion process. many types of gauges are activated by mechanical,
reformed gasoline. A high-octane gasoline obtained ultrasonic, electronic, magnetic, and pneumatic
from low-octane gasoline by heating the vapors to a means. Some operate on the principle of automatic
high temperature or by passing the vapors through a control. In materials technology, the term gauge is
suitable catalyst. often synonymous with thickness, especially in the
straight-run gasoline. Gasoline produced from pe- metals, rubber, and plastics fields. Light gauge re-
troleum by distillation without use of cracking or fers to thicknesses from about 0.005 to 0.05 inch,
598GAY-LUSSAC, JOSEPH LOUIS
and heavy gauge to thicknesses from about 0.05 to tain much solvent in the interstices (so-called
0.150 inch. “brush-heap” structure). Gels are usually transpar-
See mil; meter (2). ent but may become opalescent.
See pectin.
Gay-Lussac, Joseph Louis. (1778–1850). A
French chemist and physicist noted for the brilliance
gelatin. A mixture of proteins obtained by hydrol-
and accuracy of his reasoning and experimental ysis of collagen by boiling skin, ligaments, tendons,
etc. Its production differs from that of animal glue in
work. He contributed greatly to the knowledge of
that the raw materials are selected, cleaned, and
gases in his discovery (1808) of the law of combin-
treated with special care so that the product is clean-
ing volumes and his independent discovery (1802)
er and purer than glue. Type A gelatin is obtained
of the law of Charles, the relationship of temperature
from acid-treated raw materials, and type B from
to the volume of gases. He graduated from and
alkali-treated raw materials. Gelatin is strongly hy-
taught at the Ecole Polytechnique, becoming a full
drophilic, absorbing up to 10 times its weight of
professor in 1810. His work in chemistry was exten-
water and forming reversible gels of high strength
sive, resulting in the discovery of boron, which he
and viscosity. It can be chemically modified to make
named, with Louis-Jacques Thenard, and a variety
it insoluble in water for such special applications as
of compounds such as boron trifluoride, chloric
microencapsulation of fish nutrients for fish culture.
acid, and dithionic acid (H
2
S
2
O
6
). He identified io-
Properties: Flakes or powder; odorless; tasteless.
dine as an element, named it, and studied its proper-
Soluble in warm water and glycerol; insoluble in
ties. He investigated the relationship of acids and
organic solvents.
bases and introduced many analytical techniques
Grade: Edible, photographic, technical, USP.
(such as the use of litmus as an indicator). Among
Use: Photographic film; sizing; textile and paper ad-
his many contributions to industrial chemistry were
hesives; cements; capsules for medicinals; matches;
improvements in the production of sulfuric acid.
light filters; clarifying agent; desserts, jellies, etc.;
Much of the progress of chemistry in the early 19th
culture medium for bacteria; blood plasma volume
century is associated with his career.
expander; microencapsulation; printing inks; nutri-
ent; protective colloid in ice cream.
Gay-Lussac’s law. A modification of Charles’
law to state the following: At constant pressure the
gelatin dynamite. A high explosive that con-
volume of a confined gas is proportional to its abso-
tains nitrocellulose in addition to nitroglycerin. The
lute temperature. The volumes of gases involved in a
product is a gelatinized mass, less sensitive to shock
chemical change can always be represented by the
and friction than straight dynamite.
ratio of small whole numbers.
gel electrophoresis. A procedure for separat-
GC. Abbreviation for gas chromatography.
ing a mixture of molecules through a stationary
material (gel) in an electrical field.
GC-rich area. Many DNA sequences carry
long stretches of repeated G and C, which often
gel filtration. A type of fractionation procedure
indicate a gene-rich region.
in which molecules are separated from each other
according to differences in size and shape; the action
Gd. Symbol for gadolinium.
is similar to that of molecular sieves. Dextran gels
(three-dimensional networks of polysaccharide
GDME. Abbreviation for glycol dimethyl ether.
chains) are usually used in this method known as
See ethylene glycol dimethyl ether.
gel-filtration chromatography.
See fractionation; molecular sieve.
GDNF. Abbreviation for glial cell line-derived
neurotrophic factor.
“Gelflex Blue” [ACC Silicones]. TM for a
reusable moulding rubber.
GDP. Abbreviation for guanosine diphosphate.
See guanosine phosphates.
“Gelgard” [Dow]. TM for a synthetic polymer-
ic water-gelling material.
GDUE. See 1h,3h,5h-oxazolo(3,4-c)oxazole-
Use: Fire control.
7a(7h)-methanol.
gelled hydrogen. Liquid hydrogen thickened
Ge. Symbol for germanium.
with silica powder.
Use: Rocket fuel.
gel. A colloid in which the disperse phase has
combined with the continuous phase to produce a
viscous jellylike product. Only 2% gelatin in water
gel paint. (thixotropic paint). A paint formula-
forms a stiff gel. A gel is made by cooling a solution, tion that has a semisolid or gel consistency when
whereupon certain kinds of solutes (gelatin) form undisturbed, but that flows readily under the brush
submicroscopic crystalline particle groups that re- or when stirred or shaken. After removal of the
599 GENE TESTING
stress, it becomes stiff again and has little tendency nism in which it functioned in the same manner as
to spill, drip, or run. The thixotropic quality is ob- would a normal gene. Because of the ability of DNA
to store and transfer coded genetic instructions,
tained by the carefully controlled reaction of a rela-
genes determine the sequence of amino acids in
tively small proportion of a polyamide resin with an
specific polypeptides (see proteins), thus they pre-
alkyd resin vehicle.
scribe the structure of the proteins synthesized. In
See thixotropy.
viruses, the genes consist of ribonucleic acid (RNA).
Mutation of genes is a change in the basic sequence
gel-permeation chromatography. (GPC).
of amino acids in DNA and may be induced by
The form of liquid chromatography that sorts poly-
ionizing radiation. Mutations can occur in any living
mer molecules in a gel-packed column according to
cell. See genetic code; radiation, ionizing;
their size in solution.
recombinant DNA; molecular biology.
gelsemine.
CAS: 509-15-9. C
20
H
22
N
2
O
2
.
gene amplification. Any process by which spe-
Hazard: A toxic plant alkaloid.
cific DNA sequences are replicated disproportion-
Use: Medicine, as a CNS stimulant.
ately larger than their representation in the parent
molecules; during development, some genes be-
gel shift assay. (gel mobility shift assay
come amplified in specific tissues.
(GMSA); band shift assay (BSA); electropho-
See gene; oncogene.
retic mobility shift assay (EMSA). A method by
which one can determine whether a particular pro-
gene chip technology. Development of
tein preparation contains factors which bind to a
cDNA microarrays from a large number of genes.
particular DNA fragment. When a radiolabeled
Used to monitor and measure changes in gene ex-
DNA fragment is run on a gel, it shows a characteris-
pression for each gene represented on the chip.
tic mobility. If it is first incubated with a cellular
extract of proteins (or with purified protein), any
gene deletion. The total loss or absence of a
protein-DNA complexes will migrate slower than
gene.
the naked DNA—a shifted band.a
gene expression. The process by which a
“Gelva” [Solutia]. TM for a family of acrylic
gene’s coded information is translated into the struc-
multipolymer products designed for high-perfor-
tures present and operating in the cell (either pro-
mance, pressure-sensitive adhesive applications
teins or RNAs).
where skin adhesion, high temperature and/or diffi-
cult-to-adhere-to surface are involved. Provided for
gene families. Groups of closely related genes
both solvent and water based grades.
that make similar products.
Use: Medical, automotive, solar film, graphics, and
specialty tape products.
gene library. See genomic library.
gem-. Prefix. Abbreviation of geminate, meaning
two identical groups attached to the same carbon
gene mapping. Determination of the relative
atom.
positions of genes on a DNA molecule (chromo-
some or plasmid) and of the distance, in linkage
gemicitabine.
units or physical units, between them.
CAS: 95058-81-4. mf: C
9
H
11
F
2
N
3
O
4
.
Hazard: Human systemic effects
gene pool. All the variations of genes in a spe-
cies.
gene. A complex of nucleoproteins (chiefly DNA)
See allele; gene; polymorphism.
that is the active transmitter of genetic information.
Each of the body’s 50,000 to 100,000 genes contains
gene prediction. Predictions of possible genes
the code for a specific product, typically, a protein
made by a computer program based on how well a
such as an enzyme.
stretch of DNA sequence matches known gene se-
Genes occur on the chromosomes of every living
quences
cell, where they are arranged in a linear order. Ge-
netic mechanism is the same in all organisms, rang-
gene product. The biochemical material, either
ing from the lowest forms of life, both plant and
RNA or protein, resulting from expression of a gene.
animal, to humans. Every organism has a large num-
The amount of gene product is used to measure how
ber of different genes; there are over 10,000 in each
active a gene is; abnormal amounts can be correlated
cell of the human body. These control the intricate
with disease-causing alleles.
and well-balanced system of biochemical reactions
in the cell. The first synthesis of a gene was reported
in 1970. In 1976, it was announced that a synthetic
gene testing. See genetic testing; genetic
gene was successfully introduced into a microorga- screening.
600GENE THERAPY
gene therapy. An experimental procedure organ, etc.).
aimed at replacing, manipulating, or supplementing See protein; amino acid; ribonuclease.
nonfunctional or misfunctioning genes with healthy
genes.
genetic counseling. Provides patients and their
See gene; inherit; somatic cell gene therapy; germ
families with education and information about ge-
line gene therapy.
netic-related conditions and helps them make in-
formed decisions.
gene transfer. Incorporation of new DNA into
and organism’s cells, usually by a vector such as a
genetic discrimination. Prejudice against
modified virus. Used in gene therapy.
those who have or are likely to develop an inherited
See mutation; gene therapy; vector.
disorder.
general acid-base catalysis. Catalysis in-
volving a proton transfer from/to a molecule other
genetic engineering. Transference of genetic
than water. Compare to specific acid-base catalysis.
material from the genes of one species to those of
another by uniting a portion of the DNA of one
organism with extranuclear sections of DNA from
generic formula. See formula, chemical.
another organism (also called gene-splicing). Such
recombinant molecules will replicate in the same
“Genesolv” [General Electric]. TM for ul-
way as in normal DNA behavior. This technique is
trapure halogenated hydrocarbon solvents of the
being utilized in basic genetic research sponsored by
methane and ethane series.
the National Institutes of Health.
Properties: High densities and low viscosities, com-
There have been a number of outstanding achieve-
bined residue (soluble plus insoluble matter) is less
ments in genetic engineering in which bacteria are
than 1 ppm.
made to form chains of amino acids programmed by
Grade: Standard and electronic, Genesolv D, 200,
nucleic acids supplied by the experimenters; (1)
and 2004.
Production of human insulin from E. coli by im-
Hazard: Nonflammable, nonexplosive, thermally
planting synthetic genes in the bacterium; commer-
stable, and relatively nonhydrolyzable.
cial production of such synthetic insulin has been
Use: Removal of greases and oils from metal, plastic,
going on for some time, and the product has been
elastomer, and paint or varnish surfaces. Used with
approved by the FDA. (2) Formation and secretion
all cleaning techniques on assembled motors and
by E. coli of the protein ovalbumin. (3) Synthesis of
parts, electronic devices, precision components,
rat growth hormone in bacteria. (4) Synthesis of
motion-picture film, refrigeration systems, etc. Also
human growth hormone in bacteria; it will probably
used for isolation of viruses, for fire extinguishing,
be developed on a commercial scale. (5) Production
and as dielectric coolants.
of a biologically active protein closely similar to
interferon by exposing to the action of viruses bacte-
gene-splicing. The enzymatic attachment of one
ria that have been programmed to form it by intro-
exon to another.
duction of the appropriate genetic code. (6) Creation
See genetic engineering.
of a wholly synthetic bacterium characterized by
unusual ability to consume crude oil.
gene testing. Examining a sample of blood or
Various patents are pending on some of these tech-
other body fluid or tissue for biochemical, chromo-
niques for commercial exploitation. The Supreme
somal, or genetic markers that indicate the presence
Court has ruled that these and other results of genetic
or absence of genetic disease.
engineering are patentable inventions. See bio-
technology.
gene therapy. Treatment that alters genes (the
basic units of heredity found in all cells in the body).
genetic engineering technology. See re-
In early studies of gene therapy for cancer, research-
combinant DNA technology.
ers are trying to improve the body’s natural ability to
fight the disease or to make the tumor more sensitive
to other kinds of therapy.
genetic illness. Sickness, physical disability, or
other disorder resulting from the inheritance of one
genetic code. Information stored in the genes
or more deleterious alleles.
that program the linear sequence of amino acids
within the protein polypeptide chain synthesized
genetic information. The hereditary informa-
during cell development. The agencies involved are
tion contained in a sequence of nucleotide bases.
DNA (deoxyribonucleic acid) and RNA (ribonucle-
ic acid). It is this information code (analogous to a
computer language) that determines (1) the nature
genetic linkage map. A chromosome map
and type of an organism, i.e., its heredity, and (2) the showing the relative positions of the known genes
kind of cell structure to be formed (muscle, bone, on the chromosomes of a given species.
601 GENOME
genetic map. A diagram showing the position of
specific genes along a chromosome relative to
markers.
Branched compounds are so named to show the proper
genetic marker A gene or other identifiable
deviation, e.g., 2-methyl propane
portion of DNA whose inheritance can be followed.
See chromosome; DNA; gene; inherit.
genetic material. See genome
is a derivation of propane, not of methane. Similarly,
isopentane
genetic mosaic. An organism in which different
cells contain different genetic sequence. This can be
the result of a mutation during development or fu-
sion of embryos at an early developmental stage.
genetic polymorphism. Difference in DNA
is named 2-methylbutane. The four carbons in a
sequence among individuals, groups, or populations
straight line give the name butane, and the side group
(e.g., genes for blue eyes versus brown eyes).
is attached to the second carbon. Another pentane has
the structure
genetic predisposition. Susceptibility to a ge-
netic disease. May or may not result in actual devel-
opment of the disease.
and was once called tetramethyl pentane. Under the
genetics. The scientific study of heredity—how
Geneva System, it is named in terms of two methyl
particular qualities or traits are transmitted from
groups joined to carbon number two in a propane chain
parents to offspring.
(e.g., 2,2-dimethyl propane). Some special recommen-
dations of the Geneva System define the use of certain
genetic screening. Testing groups of individu-
suffixes: open-chain hydrocarbons with one double
als to identify defective genes capable of causing
bond end in -ene; those with two double bonds end in -
hereditary conditions.
diene (alkenes and alkadienes rather than olefins and
diolefins). Triple-bonded compounds end in -yne. Al-
genetic testing. Analyzing an individual’s ge-
cohols are named by use of the hydrocarbon name with
netic material to determine predisposition to a par-
-ol as the characteristic suffix, i.e., methanol, ethanol,
ticular health condition or to confirm a diagnosis of
etc. In order to extend this plan to polyhydric alcohols,
genetic disease.
a syllable such as di-, tri-,ortetra- is inserted between
the name of the parent hydrocarbon and the suffix -ol.
genetic variation. A phenotypic variance of a
trait in a population attributed to genetic hetero-
geneity.
“Genetron” [General Electric]. TM for a
Sulfides, disulfides, sulfoxides, and sulfones are
group of fluorinated hydrocarbons of the methane
named like ethers, the oxy term being replaced with
and ethane series.
thio-, dithio-, sulfinyl, and sulfonyl. The acids are also
Properties: Low moisture content, noncorrosive,
named in accordance with the Geneva System.
nonflammable, stable, low power requirement per
See chemical nomenclature.
unit of refrigeration, high dielectric strength.
Use: Refrigerant and foam expansion agent.
genin. The steroid portion linked to a sugar resi-
due in certain glycosides. Important genins are
found in the digitalis glycosides used as heart stimu-
Geneva System. A system of nomenclature for
lants.
organic compounds recommended in 1892. It is
based on compounds derived from hydrocarbons as
a starting point, the names corresponding to the
genome. The total DNA contained in each cell of
longest straight carbon chain present. The position is an organism. Mammalian genomic DNA (including
indicated by numbers applied to the carbons of the that of humans) contains 6x109 base pairs of DNA
straight chain, beginning with the end carbon near- per diploid cell. There are somewhere in the order of
est the substituent element or group. Normal com- a hundred thousand genes, including coding re-
pounds, in which the carbons are linked in a straight gions, 5
and 3
untranslated regions, introns, 5
and
chain, are named ethane, propane, pentane, etc. Nor- 3
flanking DNA. Also present in the genome are
mal propane is structural segments, such as telomeric and centro-
602GENOME MAPS
meric DNAs and replication origins, and intergenic ter, alcohol, and ether; insoluble in carbon disulfide,
DNA. chloroform, and benzene.
Use: Medicine, as sodium gentisate (analgesic).
genome maps. Charts that indicate the ordered
arrangement of the genes or other DNA markers
geochemistry. The study of the chemical com-
within the chromosomes.
position of the earth in terms of the physicochemical
and geological processes and principles that pro-
genome project. Research and technology-de-
duce and modify minerals and rocks. Of practical
velopment effort aimed at mapping and sequencing
importance in discovering and establishing the lim-
the genome of human beings and certain model
its of ore deposits, petroleum, tar sands, salt, sulfur,
organisms.
and other valuable resources.
See Human Genome Initiative.
geometric isomer. A type of stereoisomer in
genomic blot. A type of Southern blot specifi-
which a chemical group or atom occupies different
cally used to analyze a mixture of DNA fragments
spatial positions in relation to the double bonds. If
derived from total genomic DNA. Because genomic
the double bond is between two carbon atoms, the
DNA is very complicated, when it has been digested
isomers are called cis and trans, as in crotonic acid,
with restriction enzymes it produces a complex set
where the H and COOH reverse locations:
of fragments ranging from tens of bp to tens of
thousands of bp. However, any specific gene will be
reproducibly found on only one or a few specific
fragments. A million identical cells will produce a
million identical restriction fragments for any given
gene, so probing a genomic Southern with a gene-
If the double bond is between a nitrogen and a carbon
specific probe will produce a pattern of perhaps one
atom, the isomers are named anti and syn, as in benzal-
or just a few bands.
doxime, where the OH group shifts locations.
genomic clone. A piece of DNA taken from the
genome of a cell or animal, and spliced into a bacter-
iophage or other cloning vector. A genomic clone
may contain coding regions, exons, introns, 5
flank-
This phenomenon also occurs in saturated ring com-
ing regions, 5
untranslated regions, 3
flanking re-
pounds having three or more members in the ring, as
gions, 3
untranslated regions, or it may contain none
well as in certain coordination compounds.
of these.
See stereochemistry.
genomic library. A collection of clones made
“Geon” [B. F. Goodrich].
from a set of randomly generated overlapping DNA
CAS: 9002-86-2. TM for polyvinyl chloride formu-
fragments representing the entire genome of an or-
lated for moldings, extrusions, binders, and
ganism.
coatings.
Use: For appliance applications, electronic parts,
genomics. The study of genes and their function.
medical devices, construction applications, bottles,
wiring, and cable.
genomic sequence. See DNA.
genotype. The genetic constitution of an organ-
geothermal energy. Superheated water and
ism, as distinguished from its physical appearance
steam trapped in rock strata in areas characterized by
(its phenotype).
volcanic activity or by intrusions of molten magma.
Associated temperatures range from 150 to 300C. It
gentamicin. (gentamycin).
escapes either from natural surface vents (geysers,
CAS: 1403-66-3. C
21
H
43
N
5
O
7
.
fumaroles, hot springs) or from bore holes drilled
Properties: Amorphous solid. Mp 102–108C. Freely
through the strata. A contributing source of heat is
soluble in water, pyridine, acid solutions; moderate-
the natural radioactivity of rocks in the earth’s upper
ly soluble in methanol, ethanol, and acetone; practi-
mantle. Power was produced in Italy from geother-
cally insoluble in benzene and halogenated hydro-
mal sources as long ago as 1913; since then geother-
carbons.
mal power plants have been installed in Iceland,
Use: Antibacterial.
New Zealand, France, Hungary, Japan, Mexico, and
El Salvador. Many nonelectrical uses have been
gentian violet. USP name for methyl violet.
developed for home heating and industrial purposes,
especially in Iceland. The chief source of geother-
gentisic acid. (2,5-dihydroxybenzoic acid). mal energy in the continental U.S. is the California-
CAS: 490-79-9. C
6
H
3
(OH)
2
COOH. Nevada area. The geysers in central California have
Properties: Crystals. Mp 199–200C. Soluble in wa- been generating electric power from steam in sub-
603 GERMANIUM DIOXIDE
stantial amounts for some years. The same is true of (20C). Soluble in most oils; insoluble in glycerol.
Hawaii. Geological formations appropriate for geo- Combustible.
thermal heat are so few that this form of energy will Use: Perfumery, flavoring.
always have limited potential.
germacrone.
geranial. See citral.
CAS: 6902-91-6. mf: C
15
H
22
O.
Hazard: A poison by ingestion.
geranialdehyde. See citral.
“Germall” [Isp Europe]. TM for a broad
geraniol. (trans-3,7-diemthyl-2,6-octadien-1-
spectrum highly effective preservative.
ol). (CH
3
)
2
C:CH(CH
2
)
2
C(CH
3
):CHCH
2
OH. A ter-
pene alcohol.
“Germall 115” [Sutton].
Properties: Colorless to pale-yellow, liquid oil;
CAS: 39236-46-9. TM for imidazolidinyl urea.
pleasant geranium-like odor. D 0.870–0.890 (15C),
Use: Preservative in cosmetics.
fp 15C, bp 230C, refr index 1.4710–1.4780 (20C),
optical rotation 2 to +2 degrees. Soluble in alcohol,
germane. A germanium hydride of the general
ether, mineral oil, fixed oils; insoluble in water and
formula Ge
n
H
2n+2
.
glycerol. Combustible.
See germanium tetrahydride.
Derivation: From citronella oil (Java), citronellol-
free grades from palmerosa oil, and (synthetically)
germanium. Ge. Nonmetallic element of atomic
from pinene. These are of higher quality.
number 32, aw 72.59, valences of 2, 4; group IVa of
Grade: Standard, soap, synthetic, FCC, EOA.
the periodic table.
Use: Perfumery, constituent of synthetic fragrances
Properties: Grayish-white solid. A p-type semicon-
and synthetic linalool.
ductor, conductivity depends largely on added im-
purities, d 5.323, mp 937.4C, bp 2830C, oxidizes
geranyl acetate. (geraniol acetate).
readily at 600–700C, does not volatilize to approxi-
CAS: 105-87-3. CH
3
COOC
10
H
17
.
mately 1350C, Mohs hardness 6. Attacked by nitric
Properties: Clear, colorless liquid; odor of lavender.
acid and aqua regia; stable to water, acids, and alka-
D 0.907–0.918 (15C), bp 242C, optical rotation 2
lies in the absence of dissolved oxygen.
to +2 degrees, refr index 1.4580–1.4640 (20C). Sol-
Derivation: Recovered from residues from refining
uble in alcohol and ether; insoluble in water and
of zinc and other sources, by heating in the presence
glycerol. Combustible.
of air and chlorine. It is also present in some coals
Derivation: (1) Constituent of several essential oils.
and can be recovered from their ash.
(2) By heating geraniol and sodium acetate with
Occurrence: Missouri, Kansas, Oklahoma.
acetic anhydride.
Method of purification: The chloride is distilled and
Grade: Technical, FCC.
then hydrolyzed to the oxide, which is reduced by
Use: Perfumery, flavoring.
hydrogen to the metal. Zone melting is used for final
purification. Single crystals are made by vaporiza-
geranyl butyrate. (geraniol butyrate).
tion of germanium diiodide. The impurities in ger-
C
3
H
7
COOC
10
H
17
.
manium are of controlling importance in its use in
Properties: Colorless liquid; roselike odor. Bp 151C
transistors. These are added to high-purity germani-
(18 mm Hg), d 0.9008 (17/4C). Insoluble in water
um in trace amounts during growth of single
and glycerol; soluble in alcohol, ether. Occurs in
crystals.
several essential oils. Combustible.
Grade: Transistor, i.e., impurities 1 part in 10
10
.
Grade: FCC.
Available forms: Ingots, single crystals, pure or
Use: Perfumes and soaps, flavoring, synthetic attar of
doped, powder.
rose.
Use: Solid-state electronic devices (transistors,
diodes), semiconducting applications, brazing al-
geranyl formate. (geraniol formate).
loys, phosphors, gold and beryllium alloys, infrared-
CAS: 105-86-2. HCOOC
10
H
17
.
transmitting glass.
Properties: Colorless liquid. Bp 113 (15 mm Hg), d
0.927 (20/4C), roselike odor. Insoluble in alcohol
germanium dichloride. GeCl
2
. White powder,
and ether. Occurs in several essential oils. Combus-
mp (decomposes), decomposes in water, soluble in
tible.
germanium tetrachloride, insoluble in alcohol and
Grade: FCC.
chloroform.
Use: Perfumes and soaps, flavoring, synthetic neroli
oil.
germanium dioxide. (germanium oxide).
geranyl propionate. (geraniol propionate). CAS: 1310-53-8. GeO
2
.
C
2
H
5
COOC
10
H
17
. Properties: White powder, hexagonal, tetragonal,
Properties: Colorless liquid; roselike odor. D and amorphous.
0.896–0.913 (25C), refr index 1.4570–1.4650 Grade: Technical, semiconductor, 99.999% pure.
604GERMANIUM MONOXIDE
Use: Phosphors, transistors and diodes, infrared- disease.
transmitting glass. See genomics; somatic cell gene therapy.
germanium monoxide. GeO.
germ line genetic mutation. See mutation.
Properties: Black solid. Mp 710C (sublimes); insol-
uble in water; soluble in oxidizing agents. Available
commercially 99.999% pure.
getter. See scavenger.
germanium potassium fluoride. (potassi-
um germanium fluoride). K
2
GeF
6
.
ghatti gum. Exudation from the stem of Ano-
Properties: White crystals. Soluble in water (hot);
geissus latifolia.
insoluble in alcohol.
Properties: Colorless to pale-yellow tears, rounded
Grade: Technical.
or vermiform. Almost tasteless and odorless, par-
Hazard: Toxic material. TLV: 2.5 mg(F)/m
3
.
tially soluble in water. Can be solubilized by auto-
claving.
germanium telluride. GeTe.
Use: Thickener and protective colloid; emulsifier for
Properties: An efficient semiconductor. Mp 725C.
oils, fats, waxes.
germanium tetrachloride.
CAS: 10038-98-9. GeCl
4
.
“Ghost Remover” [Ulano]. TM for an ink
Properties: Colorless liquid. D 1.874 (25/25C), fp
haze and stencil residue remover.
49.5C (1 atm), bp 83.1C, refr index 1.464, decom-
Use: Effective on most inks and emulsions.
poses in water. Insoluble in concentrated hydrochlo-
ric acid; soluble in carbon disulfide, chloroform,
benzene, alcohol, and ether.
Giauque, William F. (1895–1982). An Amer-
Derivation: Reaction of chlorine with elemental ger-
ican chemist who achieved distinction for his studies
manium.
of the properties of matter at temperatures approach-
ing absolute zero (273C). This research established
germanium tetrahydride.
the science of cryogenics. Giauque received the No-
CAS: 7782-65-2. GeH
4
.
bel Prize in chemistry in 1949. He was professor and
Properties: Colorless gas, d 3.43 g/L, fp 165C, bp
research director at the University of California at
88C, decomposes at 350C, insoluble in water, sol-
Berkeley. One of his most significant contributions
uble in liquid ammonia, slightly soluble in hot hy-
was the invention of a magnetic cooling device that
drochloric acid.
made it possible to attain cryogenic temperatures.
Hazard: Toxic material. TLV: 0.2 ppm.
An important property of matter discovered as a
result of his work is superconductivity.
germ cell. The reproductive cells, either egg or
See cryogenics; superconductivity.
sperm cells. Germ cells are haploid and have only
one set of chromosomes (23 in all), while all other
cells have two copies (46 in all).
gibberellic acid.
CAS: 77-06-5. C
19
H
22
O
6
. A plant-growth-promoting
germicide. See bactericide.
hormone. It is a tetracyclic dihydroxylaectonic acid.
It was synthesized in 1978.
germ line. The continuation of a set of genetic
Properties: Crystals. Mp 233–235C. Slightly solu-
information from one generation to the next.
ble in water; soluble in methanol, ethanol, acetone;
See inherit.
soluble in aqueous solutions of sodium bicarbonate
and sodium acetate.
germination. The process by which a seedling
Use: Agriculture and horticulture, malting of barley
emerges and develops from a seed, or by which a
with improved enzymatic characteristics.
sporeling emerges and develops from a spore.
germ-line cell. A class of animal cells formed
gibberellin. A group of plant-growth regulators
early in embryogenesis that are set aside for repro-
(hormones), isolated in 1938 and widely distributed
ductive function (give rise to gametes). All other
in flowering plants that promotes elongation of
cells are somatic cells.
shoots and coleoptiles. They differ from auxins in
not stimulating the growth of roots and in various
germ line gene therapy. An experimental other properties. The presence of auxin appears to be
process of inserting genes into germ cells or ferti- necessary for gibberellins to function. All gibberel-
lized eggs to cause a genetic change that can be lins have closely related structures, being weak
passed on to offspring. acids with a ring system containing double bonds
Use: To alleviate effects associated with a genetic and eight asymmetric carbons.
605 “GLACIER”
metallurgical coke.
See asphalt; bitumen.
gin. An alcoholic beverage made by distilling al-
cohol through a mixture of herbs and berries (juni-
per, coriander, etc.) and adjusting to 80–100 proof.
Properties: Flash p 90F (32.3C).
Hazard: Flammable, moderate fire risk. Slight irri-
tant, intoxicant.
See gibberellic acid; plant-growth regulator.
ginkgo biloba l., root extract.
Gibbs-Duhem equation. (GDE). An exact
CAS: 90045-36-6.
thermodynamic relation that permits computation of
Hazard: Low toxicity by ingestion. Human systemic
the changes of chemical potential for one compo-
effects.
nent of a uniform mixture over a range of composi-
Source: Natural product.
tions, provided the changes of potential for each of
the other components have been measured over the
ginsenoside.
same range.
CAS: 74749-74-9.
Hazard: A poison.
Gibbs, Josiah Willard. (1839–1903). The fa-
Source: Natural product.
ther of modern thermodynamics. During his lifelong
post as professor of mathematical physics at Yale,
Girard’s reagent. (Girard’s “P”: carboxyme-
he stated the fundamental concepts embraced by the
thylpyridinium chloride hydrazide; acethydrazi-
three laws of thermodynamics, especially the nature
depyridinium chloride). C
5
H
5
NClCH
2
CONHNH
2
.
of entropy. A theorist rather than an experimenter,
(Girard’s “T”: carboxymethyltrimethyl ammo-
Gibbs was the first to expound with mathematical
nium chloride hydrazide; trimethylacethydrazide
rigor the “relation between chemical, electrical, and
ammonium chloride). (CH
3
)
3
NClCH
2
CONHNH
2
.
thermal energy and capacity for work.” It has been
Properties: White to faintly pinkish crystals; little or
said that throughout his adult life Gibbs did nothing
no odor. Mp 190–200C. Soluble in water; insoluble
but think. The results established him as a great
in oils. T is hygroscopic.
creative scientist.
Use: Separation of aldehydes and ketones from natu-
See thermodynamics.
ral oily or fatty materials; extraction of hormones.
Gibb’s free energy. See free energy.
Girbotol absorption. (amine absorption). A
process for the removal of hydrogen sulfide or car-
Gibbs phase rule. See phase rule.
bon dioxide from a gaseous mixture. An organic
amine (ethanolamine or diethanolamine, which are
Gibbs phthalic anhydride process. Oxida-
basic) is allowed to flow down a tortuous path
tion of naphthalene to phthalic anhydride with air at
through a tower where it is contacted by and absorbs
360C over vanadium pentoxide and other catalysts.
(acidic) hydrogen sulfide or carbon dioxide from the
gas to be purified as it moves up the tower. The
giga-. Prefix meaning 10
9
units (symbol
=
G). 1 Gg
amine, contaminated with these products, is then
=
1 gigagram
=
10
9
grams.
sent from the bottom of the tower to a steam stripper
where it flows countercurrent to steam, which strips
Gilbert, Walter. (1932– ). An American mo-
the hydrogen sulfide or carbon dioxide from it. The
lecular biochemist who won the Nobel Prize for
amine is then returned to the top of the tower. The
chemistry in 1980 along with Berg and Sanger for
process is widely used in the petroleum industry for
their studies of the chemical structure of nucleic
purifying refinery and natural gases and for recovery
acid. Author of many papers on theoretical physics
of hydrogen sulfide for sulfur manufacture. Remov-
and molecular biology. He has been at Harvard since
al of carbon dioxide from gases is usually done with
1972.
monoethanolamine.
gilsonite. An asphaltic material or solidified hy-
glacial. A term applied to a number of acids, e.g.,
drocarbon found only in Utah and Colorado. One of
acetic and phosphoric, that have a freezing point
the purest (9.9%) natural bitumens. Said to be the
slightly below room temperature when in a highly
first solid hydrocarbon to be converted to gasoline.
pure state. For example, glacial acetic acid is 99.8%
Hazard: Irritant, skin sensitizer.
pure and crystallizes at 16.6C.
Use: Acid, alkali, and waterproof coatings; black
varnishes, lacquers, baking enamels, and japans;
wire-insulation compounds; linoleum and floor tile;
“Glacier” [Solutia]. TM for a new class of
paving; insulation; diluent in low-grade rubber com- metal-working fluids. It is biodegradable and non-
pounds; possible source of gasoline, fuel oil, and toxic, and generates no oil mist while in use. Pro-
606GLANCE
vides low maintenance, environmental compatiblil- deep-sea floats, potting compounds, and other com-
ity, and worker safety in metal operations. posites.
Use: Desirable when aggressive metal removal and
extreme requirements are desired. For grinding,
glass, borosilicate. See glass, heat-resistant.
milling, and turning in automotive, aviation, tool-
ing, and bearings.
glass ceramic. A devitrified or crystallized form
of glass whose properties can be made to vary over a
glance. A mineralogical term meaning brilliant or wide range.
lustrous; used to describe hard, brittle materials that Properties: Rupture modulus up to 50,000 psi, d 2.5,
exhibit a bright reflecting surface when fractured. thermal shock resistance 900C, highest continuous-
Examples of such materials are hard asphalts use temperature 700C. Glass ceramics lie between
(glance pitch) and ores of certain metals such as lead borosilicate glasses and fused silica in high-temper-
glance (galena). ature capability.
Derivation: A standard glass formula to which a
nucleating agent, such as titania, has been added, is
Glaser coupling. Coupling of terminal acety-
melted, rolled into sheet, and cooled. It is then heat-
lenes by shaking an aqueous solution of cuprous
ed to a temperature at which nucleation occurs, caus-
chlorideammonium chloride and the alkyne in an
ing formation of crystals.
atmosphere of air or oxygen.
Use: Range and stove tops, laboratory bench tops,
architectural panels, restaurant heating and warming
glass. A ceramic material consisting of a uniform-
equipment, telescope mirrors.
ly dispersed mixture of silica (sand) (75%), soda ash
See nucleation; “Pyroceram”; “Cer-vit.”
(20%), and lime (5%), often combined with such
metallic oxides as those of calcium, lead, lithium,
“Glassclad 6C” [United Chemical]. TM
cerium, etc., depending on the specific properties
for a chlorine terminated polydi methylsiloxane tel-
desired. The blend (or “melt”) is heated to fusion
omer.
temperature (approximately 700–800C) and then
Use: To form a siliconized surface.
gradually cooled (annealed) to a rigid, friable state,
often referred to as vitreous. Technically, glass is an
glass electrode. See electrode, glass.
amorphous, undercooled liquid of extremely high
viscosity that has all the appearances of a solid. It has
glass enamel. A finely ground flux, basically
almost 100% elastic recovery.
lead borosilicate, intimately blended with colored
See glass, optical.
ceramic pigments. Different grades give character-
Properties: (Soda-lime glass.) Lowest electrical
istics of acid resistance, alkali resistance, sulfide
conductivity of any common material (below 10
6
resistance, or low lead release to meet requirements
mho/cm). Low thermal conductivity. High tensile
for various uses. Firing range 540–760C.
and structural strength. Relatively impermeable to
Use: For fired-on labels and decorations on glass-
gases. Inert to all chemicals except hydrofluoric,
ware, tumblers, milk bottles, beverage bottles, glass
fluosilicic, and phosphoric acids and hot, strong
containers, illuminating ware, architectural glass,
alkaline solutions. Continuous highest-use tempera-
and signs.
ture about 121C but may be higher, depending on
See porcelain enamel.
composition. Good thermal insulator in fibrous
form. Molten glass is extrudable into extremely fine
filaments. Glass is almost opaque to UV radiation;
glass fiber. (fibrous glass; fiberglass). Gener-
in the absence of added colorant it transmits 95–98% ic name for a manufactured fiber in which the fiber-
of light to which it is exposed. Noncombustible. forming substance is glass (Federal Trade Commis-
Occurrence: Natural glass is rare but exists in the sion). Noncombustible.
form of obsidian in areas of volcanic activity and Properties: Tensile strength 15 g/denier, elongation
meteor strikes. Excellent sand for glassmaking oc- 3–4%, d 2.54, no moisture regain, loses strength at
curs in Virginia (James River), Pennsylvania, Mas- >315C, softens at approximately 815C.
sachusetts, New Jersey, West Virginia, Illinois, and See glass.
Maryland; also in southern Germany and the Czech Derivation: Molten glass is extruded at high speed
Republic. through extremely small orifices.
Available forms: Plate, sheet, fiber, filament, fabric, Hazard: A suspected carcinogen. TLV: 10 mg/m
3
rods, tubing, pipe, powder, beads, flakes, hollow (dust).
spheres. Use: Thermal, acoustic, and electrical insulation
See sodium silicate. (coarse fibers in bats or sheets); decorative and utili-
Use: Windows, structural building blocks, chemical ty fabrics such as drapes, curtains, table linen, carpet
reaction equipment, pumps and piping, vacuum backing, tenting, etc.; tire cord as belt between tread
tubes, lightbulbs, glass fibers, yarns and fabrics, and carcass; filter medium; reinforced plastics; light
containers, optical equipment. Minute glass spheres transmission for communication signals; reinforce-
with partial vacuum interior and treated exterior are ment of cement products for construction use.
available for compounding with resins for use in See fiber, optical.
607 GLAUCONITE
glass, heat-resistant. (1) A soda-lime glass during cooling. Alkali borosilicates are the most
containing approximately 5% boric oxide, which
suitable types of glasses for this purpose.
lowers the viscosity of the silica without increasing
Use: Variable-tint prescription lenses that darken in
its thermal expansion. Such glasses (known as boro-
sunlight and return to original clearness indoors
silicates) have a very low expansion coefficient and
(85% light transmission when clear, 45% in sun-
high softening point (about 593C). Tensile strength
light).
is approximately 10,000 psi. Continuous-use tem-
perature 482C. Transmits UV light in higher wave-
glass, photosensitive. A glass containing a
lengths and is used in sunlight lamps and similar
small amount of a photosensitive substance such as a
equipment for this reason.
gold, silver, or copper compound. When UV light is
See “Pyrex.”
passed through a photographic negative onto the
Note: Use of borosilicate glass as a storage-disposal
surface of this glass, a latent image formed within
medium for high-level radioactive wastes has been
the glass is converted to a visible image made up of
under research for some time. Tentative conclusions
tiny metal particles when the glass is heated. In a
based on high-temperature and high-pressure auto-
special type of photosensitive glass (photosensitive
clave tests indicate that this method would be suit-
opal), the metal particles of the photographic image
able for geologic storage of such wastes.
within the glass serve as nuclei for the growth of
See radioactive waste.
nonmetallic crystals; crystalline growth is confined
(2) A pure silica glass trademarked “Vycor” that
to the area of the image. These crystalline areas are
softens at about 1482C.
dissolved much more rapidly than the adjacent glass
See silica, fused.
by hydrogen fluoride. Thus, the glass can be formed
into intricate shapes without the use of mechanical
glassine. A thin, transparent, and very flexible
tools.
paper obtained by excessive beating of the pulp. It
may contain an admixture of urea formaldehyde to
glass, plate. Plate glass has the same composi-
improve strength.
tion as window glass (soda-lime silica), differing
Use: Packaging, dust covers for books; general
from it only in method of manufacture. These differ-
household purposes.
ences are primarily (1) the longer time of annealing
(3 or 4 days), which eliminates the distortion and
glassmaker’s soap. Term for manganese diox-
strain effects of rapid cooling; and (2) intensive
ide (MnO
2
).
grinding and polishing, which removes local imper-
fections and produces a bright, highly reflecting
glass, metallic. Metal alloys having an amor-
finish.
phous atomic structure similar to that of silica glass;
achieved by cooling of the molten alloy so rapidly
glass, ruby. A deep-red glass made by incorpo-
that no crystalline structure is formed. Such alloys
rating colloidal gold into the silicate mixture. It is
are said to be harder than their crystalline counter-
used chiefly in the decorative arts.
parts and are more resistant to corrosion. Those
containing iron have unusual ferromagnetic proper-
glass, safety. See safety glass.
ties that make them suitable for use as transformer
coils.
glass transition temperature. (T
g
). The
See “Metglas.”
temperature at which an amorphous material (such
as glass or a high polymer) changes from a brittle
glass, optical. Glasses intended for vision cor-
vitreous state to a plastic state. Many high polymers,
recting and such applications as lenses for cameras,
such as acrylics, and their derivatives have this tran-
microscopes, and other instruments; must be of ex-
sition point, which is related to the number of carbon
tremely high quality and uniformity to meet require-
atoms in the ester group. The T
g
depends on its
ments for refractive index and light dispersion. Opti-
composition and extent of annealing.
cal glass may be either crown (lime) or flint (lead).
Lead oxide is a major ingredient of flint glass, im-
glass, water. See sodium silicate.
parting high refractive index and dispersion, as well
as surface brilliance. Flint glasses are also used in
Glauber’s salt. See sodium sulfate decahyd-
vacuum tubes and electrical equipment. Many spe-
rate.
cial ingredients are used in both crown and flint
glasses for specific refractivity and dispersion prop-
erties.
glauconite. K
2
(Mg, Fe)
2
Al
6
(Si
4
O
10
)
3
(OH)
12
.A
natural silicate of potassium, aluminum, iron, and
glass, photochromic. A glass that changes col- magnesium found in greensands and other sedimen-
or on exposure to light and returns to original color tary rocks.
when the light has been removed. One type is a Properties: Green in color, earthy luster. D 2.3.
silicate glass containing dispersed crystals of colloi- Occurrence: New Jersey, Virginia.
dal silver halide that is precipitated within the melt Use: Water softener, foundry molds, fertilizer.
608ALLO-GLAUCOTOXIGENIN
allo-glaucotoxigenin. isms. They are coagulated by heat; insoluble in wa-
CAS: 14155-65-8. mf: C
23
H
32
O
6
. ter; soluble in dilute solutions of salts, strong acids,
Hazard: A poison. and strong alkalies. Enzymes and acids cause hy-
Source: Natural product.
drolysis to amino acids as the only products. Exam-
ples are immune serum or -globulins in blood and
glaze. A mixture similar to porcelain enamel, ap-
myosin in muscle. The blood globulins are used in
plied to a ceramic substrate. It may refer to (1) a
immunizing against specific diseases and in medical
vitreous coating on pottery or enamelware; (2) the
research. The -globulin molecule is reported to
mixed dry powders of the batch to be used for the
consist of 19,996 atoms associated in 1320 amino
coating; or (3) a water suspension of these materials
acid units.
(wet glaze). Glazes must be low in sodium and are
(2) A protein occurring naturally in wheat and other
usually mixtures of silicates and flint, lead com-
cereal grains. See immunochemistry.
pounds, boric acid, calcium carbonate, etc.
See frit; porcelain enamel.
-globulin. See immune endoglobulin.
glaze stain. Finely ground calcined oxide of
GLP. (good laboratory practices). Refers to the
cobalt, copper, iron, and manganese.
body of regulations that govern the collection of
Use: Coloring ceramic glazes.
laboratory data. As two examples, data collected
must be traceable to the exact person who collected
GLC. Abbreviation for gas-liquid chromatogra-
the data, and computer files must have their name
phy.
changed if the file contents change.
See gas chromatography.
Glu. Abbreviation for glutamic acid.
gliadin. A prolamin occurring in gluten, the pro-
tein of wheat, rye, and other grains. Wheat gliadin
glucagon. (hyperglycemic-glycogenolytic fac-
has the following composition: 52.7% carbon,
tor; HG-factor; HGF). Produced by the cells of
17.7% nitrogen, 21.7% oxygen, 6.9% hydrogen,
the islands of Langerhans and also by the gastric
1.0% sulfur. It is composed of 18 amino acids, 40%
mucosa. It is opposite in effect to insulin. It appears
being glutamic acid. Insoluble in water, soluble in
to be a straight-chain polypeptide with a molecular
70–90% alcohol, soluble in dilute acid and in alkali.
weight of approximately 3500. Small amounts have
Use: Chemical synthesis of spinal anesthetics, phar-
been detected in commercial insulin preparations.
maceutical preparations.
Grade: USP.
Use: Medicine, biochemical research.
gliftor.
CAS: 8065-71-2. mf: C
3
H
6
ClFOC
3
H
6
F
2
O.
“Glucam E-10” [Dow]. TM for humectant
Hazard: A poison by ingestion, inhalation, and skin
from corn.
contact. An eye irritant.
Use: To reduce overall irritancy from other ingredi-
ents in hair- and skin-care preparations.
gliquidone.
CAS: 33342-05-1. mf: C
27
H
33
N
3
O
6
S.
“Glucam E-20” [Dow]. TM for humectant
Hazard: Low toxicity by ingestion. A reproductive
from corn.
hazard.
Use: For a highly active, mild skin moisturizer that
reduces water loss from cream and lotion formula-
“Globar” [Carborundum]. TM for silicon
tions.
carbide heating elements and resistors and acces-
sories.
“Glucam P-20” [Dow]. TM for a fragrance
Properties: Elements have a working temperature up
fixative.
to 1510C, which can be extended to 1648C for short
periods; low coefficient of expansion; structure not
glucase. See maltase.
affected by rapid heating and quick cooling; resis-
tance remains practically constant above 482C.
glucinium. Former name for the element berylli-
Use: Electric resistors and heating elements, termi-
um, named because the salts of beryllium are sweet
nals, and other accessories for electric heating ele-
tasting.
ments, electric heating appliances, electric furnaces.
glucocorticoid response element. See
globular proteins. Soluble proteins with a
GRE.
globular (somewhat rounded) shape. Their axial to
diameter ratio is less that 10:1, and usually closer to
1:1.
glucogenic amino acids. Amino acids with
carbon chains that can be metabolically converted
globulin. (1) Any of a group of proteins synthe- into glucose via gluconeogenesis. Contrast with ke-
sized by the body when invaded by infective organ- togenic amino acids.
609 GLUE
gluconeogenesis. The biosynthesis of a carbo- and wine making, intermediate, caramel coloring,
hydrate from simpler, noncarbohydrate precursors baking and canning, source of methane by anaerobic
such as alanine or pyruvate. fermentation, source of certain amino acids (e.g.,
lysine) by fermentation.
See glucose syrup; invert sugar.
gluconic acid. (glyconic acid; glycogenic
acid).
glucose isomerase enzyme preparations,
CAS: 299-27-4. CH
2
OH(CH
2
O)
4
COOH.
insoluble.
Properties: Pure product is crystalline; light-brown
Use: Food additive.
color. Mp 131C, d 1.24. Commercial grade is 50%
aqueous solution. Insoluble in organic solvents.
glucose oxidase. An enzyme commercially
Derivation: Bacterial, chemical, or electrochemical
available under various trademarks; catalyzes oxi-
oxidation of glucose. It is the chief acid in honey.
dation of glucose to gluconic acid. Water-soluble
Grade: Technical, 50% solution.
amorphous powder. Removes excess oxygen from
Use: Pharmaceutical and food products, cleaning and
canned foods, beer, etc., and from stored food.
pickling metals, sequestrant, cleansers for bottle
Use: Food preservative, analytical reagent for glu-
washing, paint strippers, alkaline derusters, catalyst
cose, stabilizer for vitamins C and B
12
.
in textile printing (ammonium salt).
glucose syrup. (corn syrup). A mixture of D-
glucono--lactone. (D-gluconic acid, -lac-
glucose, maltose, and maltodextrins made by hy-
tone).
drolysis of cornstarch by the action of acids or en-
CAS: 90-80-2. CH
2
OHCH(CH
2
O)
3
C(O)O.
zymes. The degree of conversion of the starch varies
Properties: White crystals. Mp 155C, bp (decom-
with consequent effect on the dextrose equivalent
poses). Readily soluble in water; slightly soluble in
(DE) or reducing power of the syrup.
alcohol.
Use: Food industry as a sweetener (high DE), thick-
Derivation: Oxidation of glucose.
ener, or bodying agent (low DE) in soft drinks.
See gluconic acid.
See glucose.
8--d-glucopyranosyl-apigenin.
-glucosidase. See maltase.
CAS: 3681-93-4. mf: C
21
H
20
O
10
.
Hazard: A poison.
-glucosidase. See emulsion.
D(+)-glucosamine.
glucoside. See glycoside.
CH
2
OH(CH
2
O)
3
CHNH
2
CHO.
Properties: ( form.) Colorless needles. Mp 110C
“Glucquat 100” [Dow]. TM for humectant
(decomposes). Very soluble in water; slightly solu-
from corn.
ble in methanol and ethanol; insoluble in ether and
Use: For conditioning, plasticizing, and foam reten-
chloroform.
tion.
Use: Biochemical research.
D(+)-glucuronic acid. COOH(CH
2
O)
4
CHO. A
glucose. (dextrose; grape sugar; corn sugar).
widely distributed substance in both plants and ani-
CAS: 50-99-7.
mals, usually occurs as part of a larger molecule as in
various gums or combined with phenols or alcohols.
Properties: Needle-like crystals. Exhibits mutarota-
tion; the form has mp 165C. Soluble in water and
alcohol.
Derivation: From gum acacia.
Use: Biochemical research, medicine.
D-glucuronolactone.
CAS: 32449-92-6. C
6
H
8
O
6
. The -lactone of glucu-
ronic acid. Found in plant gums and animal connec-
Properties: Colorless crystals or white granular
tive tissues.
powder; odorless; sweet taste. D 1.544, mp 146C.
Properties: Colorless or white powder; odorless. D
Soluble in water; slightly soluble in alcohol. It has
1.76 (30/4C), mp 172–178C. Soluble in water.
the
D (right-handed) configuration and is dextrorota-
Derivation: From glucuronic acid or by synthesis.
tory. Combustible.
Use: Growth factor, medicine, pharmaceutical inter-
Occurrence: Formed in plants by photosynthesis,
mediate.
also in the blood.
Derivation: Hydrolysis of cornstarch with acids or
enzymes, hydrolysis of cellulosic wastes.
glue. A colloidal suspension of various proteina-
Grade: Technical, USP, anhydrous, hydrated. ceous materials in water. Most familiar are those
Use: Confectionery, infant foods, medicine, brewing derived by boiling animal hides, tendons, or bones,
610GLUEGLIS
which are high in collagen. Chief sources are Hazard: A poison.
slaughterhouse wastes and fish scraps. Other ani-
mal-derived glues are made from casein (milk) and
-glutamylcysteinylglycine. See glutathion.
blood. The most important vegetable glue is made
from soybean protein. Combustible in solid form.
glutaraldehyde.
See adhesive; fish glue; collagen; gelatin.
CAS: 111-30-8. OCH(CH
2
)
3
CHO.
Properties: Liquid. D 0.72, bp 188C (decomposes),
Glueglis. TM for a composition containing chief-
fp 14C, vap press 17 mm Hg (20C). Soluble in
ly glue and glycerol used in printing-press rollers.
water and alcohol. No flash point. Nonflammable.
Has soft, rubbery consistency but is easily decom-
Grade: 99%, 50% biological solution, 25% solution.
posed by heat.
Hazard: Irritant. TLV: ceiling 0.2 ppm.
Use: Intermediate; fixative for tissues; cross-linking
glufosinate.
protein and polyhydroxy materials, tanning of soft
CAS: 53369-07-6. mf: C
5
H
12
NO
4
P.
leathers.
Hazard: Moderately toxic by ingestion.
Use: Agricultural chemical.
glutaric acid. (n-pyrotartaric acid; pentane-
dioic acid).
gluside. See saccharin.
CAS: 110-94-1. HOOC(CH
2
)
3
COOH.
Properties: Colorless crystals. Mp 97C; refr index
1.419 (106C). Soluble in water, alcohol, ether, ben-
glutamic acid. (-aminoglutaric acid; 2-ami-
zene, and chloroform.
nopentanedioic acid).
Derivation: From cyclopentanone.
CAS: 56-86-0. COOH(CH
2
)
2
CH(NH
2
)COOH. A
Use: Organic synthesis, biochemical research.
nonessential amino acid. The naturally occurring
form is
L(+)-glutamic acid.
Properties:
DL-glutamic acid (synthetic racemic glutaric anhydride. (pentanedioic acid anhy-
mix): crystals. Mp 224–227C (decomposes). Slight- dride). H
2
C(CH
2
CO)
2
O.
ly soluble in ether, alcohol, and petroleum ether. D Properties: Solid. Mp 56.5C, bp 303C. Soluble in
1.4601 (20/4C). Moderately soluble in water
L()- benzene and toluene; soluble in water on complete
glutamic acid. Mp 247–249C (decomposes), d 1.538 hydrolysis.
(20/4C)
L(+)-glutamic acid: crystals. Sublimes at Hazard: Irritant.
200C, decomposes at 247–249C. Slightly soluble in Use: Plasticizers, resin, lubricant, adhesive synthesis,
ether, acetone, cold glacial acetic acid; insoluble in dyes, and pharmaceuticals.
alcohol. D 1.538 (20/4C), specific rotation +37 to
+38.9 degrees (25C). Available commercially.
glutaronitrile. (trimethylenedicyanide; penta-
Derivation: Hydrolysis of vegetable protein (e.g.,
nedinitrile).
beet sugar waste, wheat gluten), organic synthesis
CAS: 544-13-8. NC(CH
2
)
3
CN.
based on acrylonitrile. It comprises 40% of the
Properties: Colorless to straw-colored, viscous liq-
gliadin in wheat gluten.
uid. Bp 286C, d 0.989. Soluble in water and alcohol;
Grade: FCC (
L-form).
insoluble in ether and carbon disulfide. Combus-
Use: Medicine, biochemical research, salt substitute,
tible.
flavor enhancer (
L-form only).
Use: Chemical intermediate.
See sodium glutamate.
glutathione. (-glutamylcysteinylglycine).
glutamine. (2-amino-4-carbamoylbutanoic
CAS: 70-18-8. C
10
H
17
O
6
N
3
S. A universal component
acid).
of the living cell. Contains glutamic acid, cysteine,
CAS: 56-85-9. H
2
NC(O)(CH
2
)
2
CH(NH
2
)COOH. A
and glycine. These are chemically bound but can be
nonessential amino acid. Both the
L- and DL-forms
separated by hydrolysis.
are available.
Properties: White, crystalline powder; odorless;
Properties: White, crystalline powder. Soluble in
mild, sour taste. Mp 190–192C. Soluble in water and
water; insoluble in most organic solvents. Should be
dilute alcohol.
kept dry and refrigerated. Mp (
L-form) 184–185C
Use: Nutritional and metabolic research.
(decomposes) (
DL-form) 176C. Its presence in wheat
gluten contributes to the elastic properties of flour
gluten. A mixture of many proteins in which
by hydrogen bonding and disulfide cross-linking.
gliadin, glutenin, globulin, and albumin predomi-
Derivation: Action of enzymes on gluten, from beet
nate; it occurs in highest percentage in wheat (Mani-
roots, constituent of many proteins.
toba wheat contains approximately 12%) and also to
Use: Medicine, culture media, biochemical research,
some extent in other cereal grains, usually associ-
feed additive.
ated with starch. It comprises 18 amino acids. Glu-
ten is insoluble in water and hydrophilic. Its specific
7-n-((2-((2-(glutamylamino)ethyl) adaptability to bread making is due to its elastic,
dithio)ethyl))mitomycin c. cohesive nature that enables it to retain the bubbles
CAS: 118359-59-4. mf: C
24
H
34
N
6
O
8
S
2
. of carbon dioxide evolved by leavening agents; this
611 GLYCEROL
also imparts to doughs their characteristic dilatant glycerol have been replaced by acid radicals. The
latter may be identical or different so that the glycer-
properties. This behavior is due to disulfide cross-
ide may contain up to three different acid groups.
links and hydrogen bonding between the proteins or
Glycerides can be made synthetically. The most
their constituent amino acids.
common are based on fatty acids that occur naturally
Use: Special breakfast foods and other cereals and
in oils and fats.
foods, cattle food, adhesives, production of certain
See monoglyceride; triglyceride.
amino acids.
glutenin. One of the proteins present in wheat
glycerin. See glycerol.
flour in substantial percentage. It is composed of 18
amino acids.
glycerin carbonate. (hydroxymethylethylene
carbonate).
Gluten Intolerance Group. (GIG). A non
profit group that provides support to persons with
C
H
2
O(CO)O
CHCH
2
OH.
gluten intolerances, including Celiac Disease, Der-
Properties: Pale-yellow hygroscopic liquid;
matitis Herpetiformis and other gluten sensitivities.
odorless. Boiling range 125–130C (0.1–0.2 mm
Its mailing address is 15110 10th Ave., SW, Seattle,
Hg), fp supercools to a glass, d 1.4000 (20/4C), refr
WA 98166. Website: http:/./www.gluten.net
index 1.4580 (20C), flash p 415F (212C). Miscible
with water, alcohol, ether; soluble in ethylene di-
gluten sensitive enteropothy. (GSE).
chloride; insoluble in carbon tetrachloride, benzene,
See: celiac disease.
and aliphatic hydrocarbons. Combustible.
Grade: Technical.
glutethimide. See 2-ethyl-2-phenylglutari-
Use: Solvent, intermediate.
mide.
glycerin 1-isopropyl ether.
Gly. Abbreviation for glycine.
CAS: 17226-43-6. mf: C
6
H
14
O
3
.
Hazard: Low toxicity by ingestion and inhalation. A
glycan. A general term for a polymer of monosac-
mild skin and eye irritant.
charide units joined by glycosidic bonds, may or
may not have other components, e.g. peptidoglycan.
glycerol. (glycerin; glycyl alcohol; 1,2,3-pro-
panetriol).
glycarbylamide. (4,5-imidazoledeicarboxam-
CAS: 56-81-5.
ide). C
3
H
2
N
2
(CONH
2
)
2
.
Properties: White powder. Melts above 360C. Insol-
uble in water.
Use: A coccidiostat for chickens.
glyceraldehyde. (glyceric aldehyde).
A trihydric (polyhydric) alcohol.
CAS: 56-82-6. HOCH
2
CH
2
OCHO. Isomeric with
Properties: Clear, colorless, syrupy liquid; odorless;
dihydroxyacetone. It is produced by the oxidation of
sweet taste; hygroscopic. D anhydrous 1.2653, USP
sugars in the body. As the simplest aldose, the con-
greater than 1.249 (25/25C), dynamite 1.2620, mp
formation of
D- and L-glyceraldehydes has been des-
18C, bp 290C, flash p 320F (160C), autoign temp
ignated the reference standard for
D- and L-carbohy-
739F (392C). Soluble in water and alcohol (aqueous
drates and derivatives.
solutions are neutral); insoluble in ether, benzene,
and chloroform and in fixed and volatile oils. Com-
bustible.
Derivation: (1) By-product of soap manufacture; (2)
from propylene and chlorine to form allyl chloride,
which is converted to the dichlorohydrin with hypo-
In these isomers, the central carbon atom (C*) is
chlorous acid; this is then saponified to glycerol with
asymmetric.
caustic solution; (3) isomerization of propylene ox-
Properties: (
DL-glyceraldehyde.) Tasteless crystals
ide to allyl alcohol, which is reacted with peracetic
from alcohol-ether mixture. Mp 145C. Insoluble in
acid, (the resulting glycidol is hydrolyzed to glycer-
benzene, petroleum ether, pentane.
ol); (4) hydrogenation of carbohydrates with nickel
Grade: 40% aqueous solution.
catalyst; (5) from acrolein and hydrogen peroxide.
Use: Biochemical research; intermediate; nutrition;
Method of purification: Redistillation, ion-ex-
prepraration of polyesters, adhesives; cellulose
change techniques.
modifier; leather tanning.
Grade: USP, CP (pharmaceutical and commercial,
where highest grade is required), saponification
glyceride. An ester of glycerol and fatty acids in soap lye, crude yellow distilled (for commercial
which one or more of the hydroxyl groups of the purposes where color and extreme purity are not
612GLYCEROL BORIBORATE
factors), high gravity or dynamite (dehydrated to
glycerol-lacto stearate.
Use: Food additive.
99.8–99.9% purity), natural, synthetic, FCC.
Hazard: TLV: (vapor) 10 mg/m
3
.
Use: Alkyd resins, dynamite, ester gums, pharmaceu-
glycerol monolaurate. (glyceryl monolau-
ticals, perfumery, plasticizer for regenerated cellu- rate). C
11
H
23
COOCH
2
CH
2
OCH
2
OH.
Properties: Cream-colored paste; faint odor. Mp
lose, cosmetics, foodstuffs, conditioning tobacco,
23–27C, d 0.98, FFA <2.5%, iodine value 5–8, pH
liquors, solvent, printer’s ink rolls, polyurethane
8.0–8.6 (25C) (5% aqueous dispersion). Dispersible
polyols, emulsifying agent, rubber stamp and copy-
in water; soluble in methanol and ethanol, toluene,
ing inks, binder for cements and mixes, special
naphtha, mineral oil, cottonseed oil, ethyl acetate.
soaps, lubricant and softener, bacteriostat, pene-
Combustible.
trant, hydraulic fluid, humectant, fermentation nu-
See monoglyceride.
trients, antifreeze mixtures.
Grade: Edible, technical.
Use: Emulsifying and dispersing agent for food prod-
glycerol boriborate.
ucts, oils, waxes, and solvents; antifoaming agent;
Properties: Pale-yellow liquid obtained by heating
dry-cleaning soap base.
glycerol, sodium borate, and boric acid; composi-
tion varies, soluble in cold water, absolute alcohol,
glycerol monooleate.
other alcohols, glycerol.
CAS: 25496-72-4.
Use: Adhesive, binder, fabric softener, fire-retardant
Properties: Clear amber or pale yellow liquid. Insol
on fabrics.
in water.
Use: Food additive.
glycerol dichlorohydrin. See -dichloroh-
See “Aldo MO” [Ashland].
ydrin.
glycerol monooleate. (glyceryl monooleate).
glycerol-1,3-distearate. (glyceryl-1,3-distea-
C
17
H
33
COOCH
2
CH
2
OCH
2
OH.
rate). C
39
H
76
O
5
.
Properties: Yellow oil or soft solid. D 0.95, mp
Properties: Solid. Mp 29.1. Very slightly soluble in
14–19C depending on purity, iodine value 65–80.
cold alcohol and ether; soluble in hot organic sol-
Insoluble in water; somewhat soluble in alcohol and
vents.
most organic solvents. Combustible.
See monoglyceride.
glycerol ester of partially dimerized rosin.
Grade: Edible, technical.
Properties: Hard, pale amber-colored resin. Sol in
Use: Foods, pharmaceuticals, and cosmetics; rust-
acetone, benzene; insol in water.
preventive oils; textile finishing; vinyl light stabiliz-
Use: Food additive.
ers; odorless base paints, flavoring.
glycerol ester of partially hydrogenated
glycerol monoricinoleate. (glyceryl monori-
wood rosin.
cinoleate).
Properties: Medium hard, pale amber resin. Sol in
C
6
H
13
CH
2
OC
10
H
18
COOCH
2
CH
2
OCH
2
OH.
acetone, benzene; insol in water, al