U. Symbol for uranium. els, bathroom fixtures, and business machine

housings.

“Ucar” [Dow]. TM for various synthetic organ-

UDP. Abbreviation for uridine diphosphate.

ic chemicals including solvents, coatings, resins,

See uridine phosphate.

and deicing fluids. Also applied to synthetic latexes

and water-soluble polymers.

UDPG. Abbreviation for uridine diphosphate

glucose.

“Ucarcide” [Dow]. TM for glutaraldehyde-

based antimicrobials.

Use: Preservative and sanitizing applications; oil

“Uformite” [Rohm & Haas]. TM for syn-

fields.

thetic resins based on urea-formaldehyde, mela-

See glutaraldehyde.

mine-formaldehyde, and triazine condensates. Sup-

plied as colorless or light-colored aqueous solutions

or solutions in volatile solvents. Solvent type pro-

“Ucare” [Dow]. TM for catonic hydroxyethel

duces hard, alkali-resistant, colorless coatings on

cellulose, conditioning polymer.

curing with adhesion to a variety of surfaces.

Use: Shampoos and body washes.

Use: With alkyd resins in coatings, industrial finishes

on appliances, automobiles, etc; adhesives for pa-

“Ucarsan” [Dow]. TM for a blend of glutaral-

perboard boxes, paper coatings, wet-strength paper,

dehyde and a surfactant.

textile pigment binding.

Use: As a sanitizer for agricultural equipment, such

as poultry hatcheries and farm-animal housing facil-

“Ulano Fotocoat” [Ulano]. TM for a solvent

ities; industrial equipment.

resistant emulsion.

See glutaraldehyde.

Use: For use with weak light sources.

“Ucon” [Dow]. (1) TM for a series of non-

ulexite. (cotton balls). NaCaB

•8H

O. A nat-

flammable fluorocarbon solvents and solvent blends

ural hydrated borate of sodium and calcium.

with high chemical stability and extremely low resi-

Properties: White color; silky luster. Mohs hardness

due levels.

1–2.5, d 1.96. Usually found as rounded, loose-tex-

Use: Cleaning electronic and mechanical instruments

tured masses of fine crystals.

and controls, degreasing motors, cleaning liquid

Occurrence: Chile, Argentina, California, Nevada.

oxygen equipment, and motion-picture and televi-

Use: Source of borax.

sion film and magnetic tape.

(2) TM for polyalkylene glycols and diesters. Avail-

ullage. (1) The loss by evaporation or leaking. (2)

able as water-soluble or insoluble products.

The amount a vessel lacks of being full.

Grade: LB-Series, 50-HB Series, 75-H Series, DLB

See head space.

Series, and Hydrolube Series.

Use: High-temperature lubricants, low-temperature

Ullman reaction. Synthesis of biaryls by cop-

fluids, compressor lubricants, hydraulic brake

per-induced coupling of aryl halides. Similar cou-

fluids, quenchant fluid, heat-transfer fluids, textile

pling of aryl halides with aroxides yields diaryl

lubricants, rock drill lubricants, leather and paper-

ethers. (A modification of the Fittig synthesis in

treating compounds, rubber lubricants, plasticizers

which copper powder is used instead of sodium.)

and solvents, chemical intermediate, stationary

phase in gas chromatography.

See fluorocarbon.

ulmin. One of a class of amorphous substances

resulting from the decomposition of the cellulose

and lignite tissues of plants. Ulmins represent one of

“Uconex” [Dow]. TM for a biocide that is an

the initial changes by which vegetable matter is

aqueous solution of glutaraldehyde.

converted into coal.

Use: In controlling bacteria and fungi in aqueous

metalworking fluids.

ulmin brown. See Van Dyke brown.

See glutaraldehyde.

“Ultimate” [Velocity]. TM for a lime calcium

“Ucure” [Dow]. TM for polyvinyl acetate reac-

and rust remover.

tive modifiers.

Use: Promoting reinforcement and improving disper-

sion, dimensional control, and surface quality in

“Ultimer” [Nalco]. TM for oil-free, water-sol-

molded reinforced plastic automotive exterior pan- uble polymers.

1298

1299 ULTRASTRUCTURE

Use: Water and waste-treatment processes. acid resistance, poor outdoor durability. Noncom-

bustible.

Derivation: Heating a mixture of sulfur, clay, alkali,

“Ultimet” [Haynes]. TM for a high-strength,

and a reducing agent to high temperatures.

cobalt-based alloy designed with excellent resis-

Use: Colorant for machinery and toy enamels, white

tance to pitting and general corrosion, especially in

baking enamels, printing inks, rubber products,

oxidizing acids, coupled with exceptional wear re-

soaps and laundry blues, cosmetics, textile printing.

sistance (cavitation erosion, galling, and abrasion).

Note: Used in very low percentages to intensify whi-

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

teness of white enamels, rubber compounds, laun-

welding electrodes and wire.

dered clothing, etc. by offsetting yellowish under-

Use: Fabrication into all types of process equipment.

tones, gives a “blue” rather than a “yellow” white.

“ULTI-PRO 100” [Indespec]. TM for a rub-

ultramicroscope. A development of the com-

ber processing aid.

pound optical microscope invented in 1903 by Zsig-

Use: A reactive viscosity modifier for difficult to

mondy and Siedentopf. Its essential feature is a

process rubber compounds.

strong light beam from an arc lamp, focused by

passing through two lenses, which illuminates the

“Ultisil” [Ametek]. TM for specially processed

specimen at right angles to the axis of observation.

silica textiles having improved temperature proper-

The presence of suspended colloidal particles as

ties of higher strength retention and flexibility after

small as 5 microns is detectable because of the light-

long exposures to temperatures as high as 2000F

scattering effect of the particles as they move about

(1050C).

in the suspension (Tyndall effect). Since the light

Use: Furnace curtains, stress-relief blankets, expan-

reflected or scattered by the particles is the only light

sion joints, insulations involving encapsulation of

that enters the microscope, the particles appear as

refractory wools, aerospace composites, seals, and

points of light against a dark background (dark-field

gaskets.

illumination). There is no resolution of individual

particle shape or size; the instrument shows only that

ultraaccelerator. An unusually powerful accel-

particles are present. The ultramicroscope has been

erator of rubber vulcanization, typified by thiuram

of great value in the study of colloidal suspensions,

sulfides and dithiocarbamates.

such as rubber latex, and of various biological phe-

nomena; its usefulness has diminished since the

ultracentrifuge. A high-speed rotational sepa-

advent of the electron microscope.

rating device, usually of laboratory size, capable of

See Tyndall effect.

developing a force of 250,000 times gravity. Its

major uses are in research on molecular weight dis-

“Ultraray” [Air Products]. TM for laser pure

tribution, macromolecular structure and properties

gases.

(proteins, nucleic acids, viruses) and separation of

Use: Excimer, chemical, and gas lasers are available,

solutes from solutions.

as are gases for surgical lasers.

See centrifugation.

“Ultra-San” [Milliken]. TM for antibacterial

“Ultra and Super Shield” [Ferro]. TM

in mats used by workers in the food processing or

for gelcoat liquid.

preparation, food service or related industry.

Use: For boats, recreational vehicles, trucks, sanitary

Use: To prevent microbial, unsanitary and odorous

ware, pools.

build up.

“Ultra-Clor” [Mallinckrodt]. TM for a turf

fungicide whose active ingredients are mercuric di-

ultrasonics. The science of effects of sound vi-

methyldithiocarbamate, potassium chromate, and brations beyond the limit of audible frequencies.

cadmium succinate. Used for dust, smoke, and mist precipitation; prepa-

Hazard: Highly toxic by ingestion. ration of colloidal dispersions; cleaning of metal

parts, precision machinery, fabrics, etc. Friction

welding, formation of catalysts, degassing and so-

“Ultraflex” [Baker Petrolite]. TM for micro-

lidification of molten metals, extracting flavor oils

crystalline wax.

in brewing, electroplating, drilling hard materials,

Available forms: Prills, slab, or molten.

fluxless soldering, nondestructive testing. Also used

Use: Hot-melt adhesives for coatings and packaging,

for investigation of physical properties, determina-

chewing-gum base, cosmetics, pharmaceuticals, lu-

tion of molecular weights of liquid polymers, degree

bricants, ceramics, processing aids, laminants, tex-

of association of water, and for inducing chemical

tiles, paints, rubber and elastomers, and water-

reaction. A developing application is the use of ul-

proofing.

trasonic vibration in diagnostic medicine.

ultramarine blue. (CI 77007).

Properties: Inorganic pigment, blue powder, good

ultrastructure. (fine structure). The detailed

alkali and heat resistance, low hiding power, poor structure of a specimen, such as a cell, tissue, or

1300“ULTRATEX”

organ, that can be observed only by electron micros-

umber. A naturally occurring brown earth con-

copy. taining ferric oxide together with silica, alumina,

manganese oxides, and lime. Raw umber is umber

that is ground and then levitated. Burnt umber is

“Ultratex” [Novartis]. TM for a group of sili-

umber calcined at low heat.

cone elastomeric finishes for natural and synthetic

Use: Paint pigment, lithographic inks, wallpaper

textile fabrics.

(pigment), artists’ color.

“Ultrathene” [Quantum]. TM for a series of

UMP. Abbreviation for uridine monophosphate.

ethylenevinyl acetate copolymer resins for adhe-

See uridine phosphates; uridylic acid.

sives, conversion coatings, and thermoplastic modi-

fiers. Wide range of melt indexes. Improves specific

uncertainty principle. The conclusion of

adhesion of hot-melt, solvent-based, and pressure-

Heisenberg based on quantum mechanical theory

sensitive adhesives.

that the precise position of a specific electron in an

atomic orbit cannot be determined and that conse-

ultraviolet. (UV). Radiation in the region of the

quently the ultimate nature of matter is not suscepti-

electromagnetic spectrum including wavelengths

ble to objective measurement. The result of this

from 100 to 3900 A

. UVA covers the region 315 to

concept was development of the orbital theory in

400 A

. UVB covers the region 280 to 315 A

which electron behavior is dealt with on a statistical

See radiation.

basis. Its validity was confirmed by 1930 by the

Hazard: Dangerous to eyes, overexposure causes

work of other mathematical physicists such a DeB-

severe skin burns (sunburn).

roglie, Fermi, and Schrodinger.

Use: Air sterilization in hospitals, microscopy.

See orbital theory; Heisenberg, Werner, P.

ultraviolet absorber. A substance that absorbs

uncoupling agent. A substance that uncouples

radiant energy in the wavelength of UV. The radiant

phosphorylation of ADP from electron transfer by

energy absorbed is converted to heat (thermal ener-

disrupting the pH gradient; for example, 2,4-dinitro-

gy). UV absorbers are added to unsaturated sub-

phenol.

stances (plastics, rubbers, etc.) to decrease light sen-

sitivity and consequent discoloring and degradation.

␥-undecalactone. (peach aldehyde; ␥-undecyl

Among compounds used are benzophenones, ben-

lactone; 4-hydroxy-undecanoic acid, ␥-lactone).

zotriazoles, substituted acrylonitriles, and phenol-

CAS: 710-04-3.

nickel complexes.

See absorption (2).

(CH

)

❘

HCH

❘

OO.

Properties: Colorless to light-yellow liquid; peach-

“Ultrawet” [Crompton & Knowles]. TM

like odor. D 0.941–0.944, refr index 1.450–1.454.

for a series of biodegradable linear alkylate sulfo-

Soluble in 4–5 volumes of 60% alcohol; soluble in

nate (LAS) anionic detergents or surface-active

benzyl alcohol, benzyl benzoate, and most fixed

agents (linear dodecylbenzene type).

oils. Combustible.

Available forms: Sodium or triethanolamine salts in

Derivation: By heating undecylenic acid in the pres-

liquid, slurry, flake, or bead form.

ence of sulfuric acid.

Grade: Chlorine-free, FCC.

“Ultrion” [Nalco]. TM for coagulent program.

Use: Perfumery, flavoring agent.

Use: In water and wastewater treatment.

undecanal. (n-undecylic aldehyde; hendeca-

umbellic acid. See anisic acid.

nal).

CAS: 112-44-7. CH

(CH

)

CHO.

umbelliferone.

Properties: Colorless liquid; sweet odor. D

CAS: 93-35-6. C

0.825–0.832 (25C), refr index 1.4310–1.4350

(20C), flash p 235F (112.7C). Soluble in oils and

alcohol; insoluble in glycerol and water. Combus-

tible.

Derivation: By oxidation of 1-undecanol or reduc-

tion of undecanoic acid.

Grade: FCC.

Hazard: Toxic by ingestion and inhalation, irritant to

Properties: Colorless needles. Mp 225C. Soluble in

tissue.

alcohol, acetic acid, weak alkalies, and boiling

Use: Perfumery, flavors.

water.

Derivation: Distillation of plant resins (umbellif-

erae).

n-undecane. (hendecane).

Use: Cosmetics, sunscreen preparations. CAS: 1120-21-4. CH

(CH

)

1301 UNIMOLECULAR

Properties: Colorless liquid. D 0.7402 (20/4C), fp Congealing p 21C, d 0.910–0.913 (25/25C), refr

−25.75C, bp 195.6C, refr index 1.41725 (20C), flash

index 1.4475–1.4485 (25C), flash p 295F (146C).

p 149F (65C). Combustible.

Almost insoluble in water; miscible with alcohol,

Grade: 95%, 99%, research.

chloroform, ether, benzene, and fixed and volatile

Use: Petroleum research, organic synthesis, distilla-

oils. Combustible.

tion chaser.

Derivation: Destructive distillation of castor oil.

Grade: Technical, NF.

undecanoic acid. (n-undecylic acid; hendeca-

Use: Perfumery, flavoring, plastics, modifying agent

noic acid). CH

(CH

)

COOH. Small amounts oc-

(plasticizer, lubricant additive, etc.), medicine (anti-

cur in castor oil. It is best derived from undecylenic

fungal agent).

acid by hydrogenation.

Properties: Colorless crystals. D 0.8505 (80/4C), mp

undecylenic alcohol. (n-undecylenic alcohol;

28.5C, bp 284.0C, 222.2C (128 mm Hg), refr index

10-undecen-1-ol; alcohol C-11).

1.4319 (40C). Insoluble in water; soluble in alcohol

CAS: 112-43-6. CH

:CH(CH

)

OH.

and ether.

Properties: Colorless liquid; citrus odor. D

Grade: Technical, 99%.

0.842–0.847, refr index 1.449–1.454; fp −3.0C. Sol-

Use: Organic synthesis.

uble in 70% alcohol. Combustible.

Use: Perfumes.

1-undecanol. (n-undecyl alcohol; decyl carbi-

nol; 1-hendecanol).

undecylenic aldehyde. See undecenal.

CAS: 112-42-5. CH

(CH

)

OH.

Properties: Colorless liquid; citrus odor. D

undecylenyl acetate. (10-hendecenyl ace-

0.829–0.834, refr index 1.435–1.443, mp 19C, flash

tate).

p 200F (93.3C). Soluble in 60% alcohol. Combus-

CAS: 112-19-6. CH

COO(CH

)

CH:CH

tible.

Properties: Colorless liquid; floral-fruity odor. D

Use: Perfumery, flavoring.

0.876–0.883, refr index 1.438–1.442. Soluble in

80% alcohol. Combustible.

2-undecanol. (2-hendecanol).

Use: Perfumery, flavoring.

(CH

)

OCH

Properties: Colorless liquid. D 0.8363 (20C), mp

n-undecylic acid. See undecanoic acid.

12C, bp 228–229C, flash p 235F (112.7C). Insoluble

in water; soluble in alcohol and ether. Combustible.

␥-undecyl lactone. See ␥-undecalactone.

Use: Antifoaming agent, intermediate, perfume fixa-

tives, plasticizer.

undulipodium. See flagellum.

2-undecanone. See methyl nonyl ketone.

UNH. Abbreviation for uranyl nitrate hydrated.

See uranyl nitrate.

undecenal. (undecylenic aldehyde; hendecen-

1-al). Listed by different authorities as 10-un-

unhairing. (dehairing). Removal of hair from

decenal, CH

:CH(CH

)CHO, and 9-undecenal.

hides and skins as practiced on a commercial scale in

CH:CH(CH

)

CHO.

the leather industry. Several methods are used, in-

Properties: Colorless liquid; strong odor suggesting

volving application of hydrated lime, dimethyl-

rose. D 0.840–0.850 (25/25C), refr index

amine, trypsin, and other enzymes.

1.4410–1.4470 (20C). Soluble in 80% alcohol.

Combustible.

“Unicarb” [Dow]. TM for spray-coatings sys-

Use: Perfumery, flavoring.

tem employing supercritical fluid technology that

significantly reduces VOC and HAP emissions.

10-undecenoic acid. See undecylenic acid.

“Unicel” [Du Pont]. TM for blowing agents

2-undecenol. mf: C

for natural and synthetic rubber sponge.

Properties: White to sltly yellow liquid; oily, sweet,

floral odor. D: 0.847, refr index: 1.450 @ 22°. Insol

“Unichrome” [ATOTECH]. (copper pyro-

in water.

phosphate). TM for electroplating.

Use: Food additive.

Use: Printed circuit boards.

10-undecen-1-ol. See undecylenic alcohol.

“Unilin” [Baker Petrolite]. TM for an al-

cohol.

n-undecyl alcohol. See 1-undecanol.

undecylenic acid. (10-undecenoic acid). unimolecular. Occurring to or within a single

CAS: 112-38-9. CH

:CH(CH

)

COOH. molecule like intramolecular, but can refer to frag-

Properties: Light-colored liquid; fruity-rosy odor. mentation reactions.

1302“UNIPOL”

“Unipol” [Dow]. TM for low pressure, gas- ysis, esterification, and nitration are examples.

phase process technology. See kinetics, chemical; chemical engineering.

Use: Production of polyethylene and polypropylene.

“Unival” [Dow]. TM for high-density polyeth-

ylene resins.

uniport. A transport system that carries only one

Use: Milk, juice, and water bottles.

solute. Contrast with cotransport.

uns-. (unsym). Abbreviation for unsymmetrical.

“UniSeal” [Unitex]. TM for a high end harden-

A prefix denoting the structure of organic com-

ing and dustproofing compound that is chemically

pounds in which substituents are disposed unsym-

reactive.

metrically with respect to the carbon skeleton or to a

Use: To permanently bond concrete.

functional group, such as a double bond. For exam-

ple, unsdichloroethane is CH

CHCl

United States Department of Agriculture.

(USDA). The federal regulatory authority for

unsaponifiable matter. The weight of matter

meats and meat products. It attempts to support

extracted by ether from the aqueous alkaline solu-

production of agriculture, ensure a safe, affordable,

tion after complete saponification of a fat or oil.

nutritious, and accessible food supply, care for agri-

cultural, forest, and range lands, support sound de-

unsaturated fatty acid. A fatty acid contain-

velopment of rural communities, provide economic

ing one or more double bonds.

opportunities for farm and rural residents, expand

global markets for agricultural and forest products

and services, and work to reduce hunger in America

unsaturation. Of a chemical compound, the

and throughout the world. Its central office is at 14th state in which not all the available valence bonds

& Independence Ave., SW, Washington, DC 20250. along the alkyl chain are satisfied; in such com-

Website: http://www.usda.gov. pounds the extra bonds usually form double or triple

bonds (chiefly with carbon). Thus, unsaturated com-

pounds are more reactive than saturated compounds

United States Pharmacopeia. (USP). An

because other elements readily add to the unsatu-

independent, science-based public health organiza-

rated linkage. An unsaturated compound (ethylene,

tion and the official public standards-setting author-

; butadiene, C

; benzene, C

) has fewer

ity for all prescription and over-the-counter medi-

hydrogen atoms or equivalent groups than the corre-

cines, dietary supplements, and other healthcare

sponding saturated compound (ethane, C

; bu-

products manufactured and sold in the United

tane, C

; cyclohexane, C

States. USP sets standards for the quality of these

In structural formulas unsaturation may be repre-

products and works with healthcare providers to

sented by parallel lines joining the carbon atoms

help them reach the standards. USP’s standards are

(ethylene, H

C==CH

; butadiene

also recognized and used in more than 130 coun-

C==CHCH==CH

) or by colons or triple dots,

tries. These standards have been helping to ensure

C:CH

(ethylene) and HC...CH (acety-

good pharmaceutical care for people throughout the

lene). See carboxyl group.

world for more than 185 years.

The USP is a self-sustaining nonprofit organization

and is funded through revenues from the sale of

unstable compound system. See peritectic

products and services that help to ensure good phar- system.

maceutical care. USP’s contributions to public

health are enriched by the participation and over-

UPS. Abbreviation for ultraviolet photoelectron

sight of volunteers representing pharmacy, medi-

spectroscopy.

cine, and other healthcare professions as well as

academia, government, the pharmaceutical indus-

upstream activator sequence. A binding

try, health plans, and consumer organizations.

site for transcription factors, generally part of a pro-

Website: http://www.usp.org.

moter region. A UAS may be found upstream of the

TATA sequence (if there is one), and its function is

“Unithox” [Baker Petrolite]. TM for ethoxy-

(the same as an enhancer) to increase transcription.

lated grade alcohol.

Unlike an enhancer, it can not be positioned just

anywhere or in any orientation.

unit operation. A particular kind of physical

change used in the industrial production of various

upstream/downstream. In an RNA, anything

chemicals and related materials. Filtration, evapora-

towards the 5

′

end of a reference point is “upstream”

tion, distillation, fluid flow, and heat transfer are

of that point. This orientation reflects the direction

examples.

of both the synthesis of mRNA and its translation—

See chemical engineering.

from the 5

′

end to the 3

′

end. In DNA, the situation is

a bit more complicated. In the vicinity of a gene (or

unit process. A process characterized by a par- in a cDNA), the DNA has two strands, but one strand

ticular kind of chemical reaction; oxidation, hydrol- is virtually a duplicate of the RNA, so its 5

′

and 3

′

1303 URANIUM-233

ends determine upstream and downstream, respec- nean waters; marking water for air-sea rescues; clin-

tively. ical test solution.

Note: that in genomic DNA two adjacent genes may

be on different strands and thus oriented in opposite

uraninite. UP

. A natural phosphide of uranium

directions. Upstream or downstream is only used on

usually partly oxidized to UO

with variable

conjunction with a given gene.

amounts of lead, radium, thorium, rare-earth metals,

helium, argon, nitrogen. Pitchblende is an important

variety.

“Urac” [Cytec]. TM for products based on urea-

Occurrence: Colorado, Utah, South Africa, Canada,

formaldehyde condensates used mainly as adhe-

Europe, the former U.S.S.R., Australia, Zaire.

sives for the production of moisture-proof bonds in

Use: Source of uranium and radium.

plywood manufacture, plywood assembly, and fur-

niture manufacture.

uranium.

CAS: 7440-61-1. U. Metallic element number 92; a

uracil. (2,4-dioxypyrimidine).

member of the actinide series; aw 238.029; valences

CAS: 66-22-8. HNC(O)NHC(O)CHCH. A pyrimi-

of 3, 4, 6; three natural radioactive isotopes: urani-

dine that is a constituent of ribonucleic acids and the

um-234 (0.006%), uranium-235 (0.7%), and urani-

coenzyme, uridine diphosphate glucose.

um-238 (99%).

Properties: Crystalline needles. Mp 335C (decom-

Properties: Dense, silvery solid. D 19.0, mp 1132C,

poses). Soluble in hot water, ammonium hydroxide,

bp 3818C, heat of fusion 4.7 kcal/mole, heat capaci-

and other alkalies; insoluble in alcohol and ether.

ty 6.6 cal/mole/C. Strongly electropositive, ductile

Derivation: Hydrolysis of nucleic acids, precipita-

and malleable, poor conductor of electricity. Forms

tion from urea and ethyl formylacetate. Radioactive

solid solutions (for nuclear reactors) with molybde-

forms available.

num, niobium, titanium, and zirconium. The metal

Use: Biochemical research.

reacts with nearly all nonmetals. It is attacked by

water, acids, and peroxides, but is inert toward alka-

uracil-6-carboxylic acid. See orotic acid.

lies. Green tetravalent uranium and yellow uranyl

ion (UO

) are the only species that are stable in

“Uracil Mustard” [Pfizer]. TM for 5-[bis(2-

solution.

chloroethyl)amino]uracil. An antineoplastic.

Occurrence: Pitchblende (essentially UO

), a variety

of uraninite, coffinite (USiO

) and carnotite (Colo-

uracil, D-ribosyl. See uridine.

rado, New Mexico, France, Zaire, Canada, South

Africa, Australia, the former U.S.S.R.). U.S. re-

“Uramite” [Du Pont]. TM for a fertilizer de-

sources of uranium oxide in the 1970s were estimat-

rived from ureaformaldehyde containing 38% ni-

ed at 150,000–175,000 tons; there is about the same

trogen.

amount in Canada.

Derivation: Finely ground ore is leached under oxi-

“Uramon” [Du Pont]. TM for solutions of

dizing conditions to give uranyl nitrate solution. The

urea in aqueous ammonia.

uranyl nitrate, purified by solvent extraction (ether,

Use: Manufacture of mixed fertilizers.

alkyl phosphate esters), is then reduced with hydro-

gen to uranium dioxide. This is treated with hydro-

urania. See uranium dioxide.

gen fluoride to obtain uranium tetrafluoride, fol-

lowed by either electrolysis in fused salts or by

urania-thoria. Crystals of the mixed oxides of

reduction with calcium or magnesium. Uranium can

uranium and thorium are available. The crystals are

also be recovered from phosphate sand.

denser and cheaper than the pellet form.

Available forms: Solid pure metal, alloys, powder

Use: Nuclear fuel.

(99.7%).

Hazard: (Powder) Dangerous fire risk, ignites spon-

uranic chloride. See uranium tetrachloride.

taneously in air. Highly toxic, radioactive material,

source of ionizing radiation. TLV: (including metal

uranic oxide. See uranium dioxide.

and all compounds, as uranium) 0.2 mg/m

; STEL

0.6 mg(U)/m

Use: Source of fissionable isotope uranium-235,

uranine. (uranine yellow; sodium fluorescein;

source of plutonium by neutron capture, electric

resorcinolphthalein sodium; CI 45350).

power generation.

CAS: 518-47-8. Na

See enrichment (2); uranium compounds.

Properties: Orange-red powder; odorless. Hygros-

copicl soluble in water; sparingly soluble in alcohol.

Derivation: By treatment of fluorescein with sodium

uranium-233. (

233

U). A fissionable isotope of

carbonate solution and crystallizing. uranium produced artificially by bombarding thori-

Method of purification: Recrystallization. um-232 with neutrons. Used as an atomic fuel in

Grade: Technical, USP (as sodium fluorescein). molten salt reactor and is a possible fuel in breeder

Use: Dyeing silk and wool yellow; tracing subterra- reactors. Half-life 1.62 × 10

years.

1304URANIUM-234

uranium-234. (

234

U). A natural isotope of urani- uranium, depleted. Uranium from which most

um with half-life of 2.48 × 10

years; it is separated of the uranium-235 isotope has been removed.

by extraction with trioctylphosphine oxide. Properties: Uranium metal wherein uranium-235

Use: Nuclear research, with potential use in fission isotopic content has been reduced below 0.7% as

detectors for counting fast neutrons. found in normal uranium. Has high structural

strength coupled with high density of 18.9 g/cc.

Derivation: Processed from uranium hexafluoride as

uranium-235. (

235

U). The readily fissionable

tailing from gaseous diffusion plants.

isotope of uranium used to enrich natural uranium in

Use: Balance weights for aircraft, high-speed rotors

nuclear fuels. It is present in uranium only to the

in gyro-compasses, ␥-radiation shielding, radio-iso-

extent of 0.7% and can be separated from it by any of

tope transportation casks and fuel element transfer

several methods: the gaseous diffusion process us-

casks, in general as structural material applicable to

ing uranium hexafluoride, the gas centrifuge pro-

radiation shielding.

cess, and the electromagnetic separation method. Its

See uranium-238.

half-life is 7.13 × 10

years. It was the energy source

used in the original atomic bomb. Its critical mass is

about 33 lb.

uranium dicarbide. (uranium carbide). UC

See fission; uranium.

Properties: Gray crystals. D 11.28 (18C), mp 2350C,

bp 4370C. Decomposes in water; slightly soluble in

alcohol.

uranium-238. (

238

U). The abundant isotope of

Hazard: Highly toxic, radiation risk.

uranium of which it comprises 99%. It is not fission-

Use: Crystals, pellets, or microspheres for nuclear

able but will form plutonium-239 as a result of

reactor fuel.

bombardment by neutrons in a reactor. Its half-life is

4.51 × 10

years. It will be used in breeder reactors,

together with plutonium, where its energy potential

uranium dioxide. (uranium oxide; uranic ox-

will be exploited by transmuting it to fissionable

ide; urania; yellowcake).

plutonium.

CAS: 1344-57-6. UO

See breeder.

Properties: Black crystals. D 10.9, mp 3000C. Insol-

uble in water; soluble in nitric acid and concentrated

sulfuric acid.

uranium carbide. See uranium dicarbide.

Derivation: (pure oxide) Powdered uranium ore is

digested with hot nitric-sulfuric acid mixture and

uranium compounds. Before the advent of

filtered to remove the insoluble portion. Sulfate is

nuclear energy, uranium had very limited uses. It

precipitated from the solution with barium carbon-

had been suggested for filaments of lamps. A small

ate, and uranyl nitrate is extracted with ether. After

tube of uranium dioxide, UO

, connected in series

re-extraction into water, it is heated to drive off nitric

with the tungsten filaments of large incandescent

acid, leaving uranium trioxide. The latter is reduced

lamps used for photography and motion pictures,

with hydrogen to the dioxide. Can be prepared from

tends to eliminate the sudden surge of current

uranium hexafluoride by treating with ammonia and

through the bulbs when the light is turned on, there-

subsequent heating of the ammonium diuranate. It is

by extending their lives. Compounds of uranium

also recovered from phosphoric acid.

have been used in photography for toning, and in the

Hazard: High radiation risk. Ignites spontaneously

leather and wood industries uranium compounds

in finely divided form.

have been used for stains and dyes. Uranium salts

Use: A crystalline (or pellet) form is used to pack

are mordants of silk or wool. In making special

nuclear fuel rods.

steels, a little ferrouranium has been utilized, but its

value is questionable in this connection. Such alloys

uranium, enriched. Natural uranium to which

have not proved commercially attractive. In the pro-

a few percent of the fissionable 235-isotope has been

duction of ceramics, sodium and ammonium diura-

added.

nates have been used to produce colored glazes.

See enrichment.

Uranium carbide has been suggested as a good cata-

lyst for the production of synthetic ammonia. Urani-

um salts in small quantities are claimed to stimulate

uranium hexafluoride.

plant growth, but large quantities are clearly poison-

CAS: 7783-81-5. UF

ous to plants.

Properties: Colorless, volatile crystals. Sublimes,

By far the most important use of uranium lies in its

triple point 64.0C (1134 mm Hg), mp 64.5C (2 atm),

application for nuclear (or atomic) energy.

d 5.06 (25C). Soluble in liquid bromine, chlorine,

carbon tetrachloride, sym-tetrachloroethane, and

uranium decay series. (uranium-radium se- fluorocarbons. Reacts vigorously with water, alco-

ries). The series of elements produced as successive hol, ether, and most metals. Vapor behaves as nearly

intermediate products when the element uranium perfect gas.

undergoes spontaneous natural radioactive disinte- Derivation: (1) Triuranium octoxide (U

) and ni-

gration into lead. Radium and radon are members of tric acid react to form a solution of uranyl nitrate;

this series. this is decomposed to UO

and reduced to the diox-

1305 UREA-AMMONIUM ORTHOPHOSPHATE

ide with hydrogen. The dioxide as a fluidized bed is Properties: Yellow, rhombic crystals. D 2.807, mp

60.2C, bp 118C. Soluble in water, alcohol, and

reacted with hydrogen fluoride. The resulting tetra-

ether.

fluoride is fluorinated to the hexafluoride. (2) Triur-

Derivation: Action of nitric acid on uranium octox-

anium octoxide is converted directly to the hexaf-

ide (U

luoride with hydrogen fluoride and fluorine, then

Hazard: Strong oxidizer. Corrosive and irritating.

purified by fractional distillation.

Use: Source of uranium dioxide, extraction of urani-

Hazard: Highly corrosive; radiation risk.

um into nonaqueous solvents.

Use: Gaseous diffusion process for separating iso-

topes of uranium.

urban waste. Solid waste materials including

garbage, cellulosics, glass, metals, etc., but not sew-

uranium hydride. UH

age (municipal waste). Garbage is being used both

Properties: Brown-gray to black powder. D 10.92,

directly as fuel and fermented to yield proteins; the

conductor of electricity.

cellulosic portion can be hydrolyzed to glucose,

Derivation: Action of hydrogen on hot uranium.

which is in turn converted to methane by anaerobic

Hazard: Highly toxic. Ignites spontaneously in air.

fermentation. A continuous process for this opera-

Use: Preparation of finely divided uranium metal by

tion utilizing newspapers or sawdust has been re-

decomposition, separation of hydrogen isotopes, re-

ported.

ducing agent, laboratory source of pure hydrogen.

See waste control; biomass.

uranium monocarbide. UC.

urea. (carbamide).

Properties: Lumps or powder that can be formed into

CAS: 57-13-6. CO(NH

)

desired shapes by powder metallurgy or arc-melt

casting. Mp 2375C, d 13.63, thermal conductivity

0.08 cal/sec/cm

/C/cm. Must be stored in inert atmo-

sphere.

Hazard: Radioactive poison.

Occurs in urine and other body fluids. The first organ-

uranium nitrate.

ic compound to be synthesized (Wohler, 1824).

CAS: 15905-86-9. mf: HNO

•xU.

Properties: White crystals or powder; almost

Properties: IDLH 10 mg/m

(as U).

odorless; saline taste. D 1.335, mp 132.7C, decom-

Hazard: A poison.

poses before boiling. Soluble in water, alcohol, and

benzene; slightly soluble in ether; almost insoluble

in chloroform. Noncombustible.

uranium oxide. See uranium dioxide.

Derivation: Liquid ammonia and liquid carbon diox-

ide at 1750–3000 psi and 160–200C react to form

uranium tetrafluoride. (green salt).

ammonium carbamate, NH

, which decom-

CAS: 10049-14-6. UF

poses at lower pressure (about 80 psi) to urea and

Properties: Green, nonvolatile, crystalline powder.

water. Several variations of the process include

D 6.70, mp 1036C. Insoluble in water.

once-through, partial recycle, and total recycle.

Derivation: Treatment of uranium dioxide with hy-

Method of purification: Crystallization.

drogen fluoride.

Grade: Technical, CP, USP, fertilizer (45–46% ni-

Hazard: Highly corrosive, radioactive poison.

trogen), feed grade (about 42% nitrogen).

Use: Intermediate in preparation of uranium metal.

Use: Fertilizer, animal feed, plastics, chemical inter-

See uranium hexafluoride.

mediate, stabilizer in explosives, medicine (diuret-

ic), adhesives, separation of hydrocarbons (as urea

uranocene. (bis-cyclooctatetraenyluranium). A

adducts), pharmaceuticals, cosmetics, dentifrices,

synthetic metallocene “sandwich” molecule whose

sulfamic acid production, flameproofing agents,

unique feature is that the pi-molecular orbitals of the

viscosity modifier for starch or casein-based paper

large organic rings share electrons with f-atomic

coatings, preparation of biuret.

orbitals of the uranium.

See urea-formaldehyde resin.

See metallocene.

urea adduct. See inclusion complex.

uranyl acetate.

CAS: 541-09-3. UO

)

urea ammonia liquor. A solution of crude

Properties: (Dihydrate) Yellow crystals. D 2.89.

urea in aqueous ammonia containing ammonium

Soluble in water plus acetic acid; slightly soluble in

carbamate.

alcohol.

Use: Reaction with superphosphate in preparation of

Use: Bacterial oxidation activator, copying inks, re-

fertilizers, furnishing combined nitrogen.

agent.

uranyl nitrate. (uranium oxynitrate; UNH; urea-ammonium orthophosphate. A fertil-

yellow salt). izer developed especially for food-deficient regions,

CAS: 10102-06-4. UO

(NO

)

•6H

O. particularly rice-dependent areas. Several grades

1306UREA-AMMONIUM POLYPHOSPHATE

contain all three primary plant nutrients (nitrogen, Grade: Technical, sometimes compounded with

phosphorus, and potassium). Contains up to 60% waxes in pellet form.

nitrogen, phosphoric anhydride, and potassium Hazard: Dangerous fire risk in contact with organic

oxide. materials; strong oxidizing agent. Irritant.

Use: Source of water-free hydrogen peroxide,

bleaching disinfectant, cosmetics, pharmaceuticals,

urea-ammonium polyphosphate. A fertiliz-

blueprint developer, modification of starches.

er similar to urea-ammonium orthophosphate ex-

cept that about half the phosphorus is in polyphos-

urea phosphoric acid. See carbamide phos-

phate form, which gives improved sequestering

phoric acid.

action and solubility. It is excellent for use as a liquid

fertilizer.

urease. Enzyme present in low percentages in

jack bean and soybean; watersoluble, its action is

urea cycle. A metabolic pathway in vertebrates

inhibited by heavy-metal ions. Its principal use is in

for the synthesis of urea from amino groups and

the determination of urea in urine, blood, and other

carbon dioxide; occurs in mitochondrial and cyto-

body fluids; it splits urea into ammonia and carbon

plasmic compartments of the liver.

dioxide or ammonium carbonate.

ureaform. A urea-formaldehyde reaction prod-

Urech cyanohydrin method. Cyanohydrin

uct that contains more than one molecule of urea per

formation by addition of alkali cyanide to the car-

molecule of formaldehyde. It can be used as a fertil-

bonyl group in the presence of acetic acid (Urech);

izer because of its high nitrogen content, its insolu-

or by reaction of the carbonyl compound with anhy-

bility in water, and its gradual decomposition in the

drous hydrogen cyanide in the presence of a basic

soil during the growing season to yield soluble ni-

catalyst (Ultee).

trogen.

Urech hydantoin synthesis. Formation of

urea-formaldehyde resin. An important class

hydantoins from ␣-amino acids by treatment with

of amino resin. Urea and formaldehyde are united in

potassium cyanate in aqueous solution and heating

a two-stage process in the presence of pyridine,

of the salt of the intermediate hydantoic acid with

ammonia, or certain alcohols with heat and control

25% hydrochloric acid.

of pH to form intermediates (methylolurea, dime-

thylolurea) that are mixed with fillers to produce

ureotelic. Organisms which excrete excess nitro-

molding powders. These are converted to thermo-

gen in the form of urea.

setting resins by further controlled heating and pres-

sure in the presence of catalysts. These were the first

urethane. (ethyl carbamate; ethyl urethane).

plastics that could be made in white, pastel, and

CAS: 51-79-6. CO(NH

)OC

. Its structure is typi-

colored products.

cal of the repeating unit in polyurethane resins.

Use: Scale housings, dinnerware, interior plywood,

Properties: Colorless crystals or white powder;

foundry core binder, flexible foams, insulation.

odorless, saltpeter-like taste. D 0.9862, mp 49C, bp

See amino resin; melamine resin.

180C. Solutions neutral to litmus. Soluble in water,

alcohol, ether, glycerol, and chloroform; slightly

urea hydrogen peroxide. See urea per-

soluble in olive oil. Combustible.

oxide.

Derivation: (1) By heating ethanol and urea nitrate to

120–130C; (2) by action of ammonia on ethyl car-

urea nitrate.

bonate or ethyl chloroformate.

CAS: 124-47-0. CO(NH

)

•HNO

Grade: Technical, NF.

Properties: Colorless crystals. Decomposes at 152C.

Hazard: Toxic by ingestion.

Slightly soluble in water; soluble in alcohol.

Use: Intermediate for pharmaceuticals, pesticides,

Derivation: By adding an excess of nitric acid to a

and fungicides; biochemical research; medicine

strong aqueous solution of urea.

(antineoplastic).

Hazard: Dangerous fire and explosion risk.

See polyurethane.

Use: Explosives, manufacture of urethane.

urethane alkyd. (uralkyd). A urethane resin

modified with a drying oil (linseed or safflower) for

urea peroxide. (urea hydrogen peroxide; per-

use in high-quality paints.

carbamide; carbamide peroxide).

CAS: 124-43-6. CO(NH

)

•H

Properties: White crystals or crystalline powder. Mp

“UrethHall” [Hall]. TM for polyester polyols

(decomposes) 75–78C, decomposed by moisture at for urethane systems that are fluid and pourable at

temperatures around 40C. Soluble in water, alcohol, room temperature and are based on chemistry com-

and ethylene glycol; solvents such as ether and ace- pletely different from the traditional adipate polyes-

tone extract hydrogen peroxide and may form explo- ters. Available in 25 different variations of glycol

sive solutions. Active oxygen (min) 16%. base, hydroxyl number, or molecular weight.

1307 USAN

Use: All forms of polyurethanes made from polyes-

uridine diphosphate glucose. (UDPG). A

ters, especially those where improved hydrolytic

coenzyme that acts in the transfer of glucose from

stability and flexibility without external plasticizers

the coenzyme to another chemical compound during

are valued.

the reaction for which the coenzyme is a catalyst.

Use: Biochemical research.

Urey, Harold C. (1894–1981). An American

uridine monophosphate. See uridylic acid.

chemist who received the Nobel Prize in chemistry

in 1934 for his discovery of the heavy isotopes of

uridine phosphate. A nucleotide used by the

hydrogen and oxygen. His discovery that became an

body in growth processes; important in biochemical

important factor in the development of nuclear fis-

and physiological research. Those isolated and com-

sion and fusion and made possible the production of

mercially available (as sodium salts) are the mono-

the first transuranic element Pu. He was one of the

phosphate (UMP), the diphosphate (UDP), and the

leaders of the Manhattan Project, which constructed

triphosphate (UTP).

the first nuclear reactor at the University of Chicago

See uridine diphosphate glucose (UDPG).

and eventually produced the first atomic bomb. Af-

ter obtaining his doctorate at the University of Cali-

uridylic acid. (uridine phosphoric acid;

fornia in 1923, he taught at several leading universi-

UMP; uridine monophosphate).

ties, including Columbia, where he discovered

CAS: (5

′

) 58-97-9. (C

P). The monophos-

deuterium D oxide (heavy water), used as a modera-

phoric ester of uracil, i.e., the nucleotide containing

tor in early types of nuclear reactors. Later he devot-

uracil-d-ribose and phosphoric acid. The phosphate

ed much study to the origin of the universe and the

may be esterified to either the 2, 3, or 5 carbon of

origin of life on earth. He was the author of many

ribose, yielding uridine-2

′

-phosphate, uridine-3

′

scientific treatises and made notable contributions

phosphate, and uridine-5

′

-phosphate, respectively.

to the cosmological theories.

Properties: (Uridine-3

′

-phosphate) Crystallizes in

prisms from methanol. Mp 202C (decomposes).

uric acid. (lithic acid; uric oxide; 2,6,8-triox-

Freely soluble in water and alcohol; dextrorotatory

ypurine).

in solution.

CAS: 69-93-2.

Derivation: (of commercial product) From yeast ri-

bonucleic acid. Also made synthetically; radioactive

❘

NHC(O)NHC

❘

CNHC(O)N

❘

H (keto form).

forms available.

Use: Biochemical research.

May also be written in enolic form. The end product

of purine metabolism in human and other primates,

uroformine. (urotropin, formin, crystogen,

birds, and some dogs and reptiles.

cystamine).

Properties: Odorless, white crystals; tasteless. D

See hexamethyltetramine.

1.855–1.893, mp (decomposes). Soluble in hot con-

centrated sulfuric acid; very slightly soluble in wa-

uronic acid. Any of a class of compounds simi-

ter; insoluble in alcohol and ether; soluble in glycer-

lar to sugars but differing from them in that the

ol, solutions of alkali hydroxides, sodium acetate,

terminal carbon has been oxidized from an alcohol

and sodium phosphate.

to a carboxyl group. The most common are galactu-

Derivation: From guano.

ronic acid and glucuronic acid.

Grade: Technical, reagent.

Hazard: Evolves a highly toxic hydrogen cyanide

ursin. See arbutin.

when heated.

Use: Organic synthesis.

urushiol. Mixture of catechol derivatives.

Properties: Pale-yellow liquid. D 0.968, bp 200C.

uricotelic. Organisms which excrete excess ni-

Soluble in alcohol, ether, and benzene.

trogen in the form of uric acid (urate at physiological

Derivation: Poison ivy (Rhus toxicodendron).

conditions).

Hazard: The toxic principle of poison ivy. Causes

severe allergenic dermatitis.

uridine. (D-ribosyl uracil).

urylon. A polyurea synthetic fiber made by con-

CAS: 58-96-8. C

. The nucleoside of uracil.

densation of nonamethylenediamine and urea.

It is a constituent of ribonucleic acid and some coen-

Properties: D 1.07, softening p 205C, mp 235C,

zymes (such as uridine diphosphate glucose).

weakens on heating to 150C or long exposure to

Properties: White powder; odorless; slightly acrid

light.

and faintly sweet taste. Mp 165C. Soluble in water;

Use: Fiber blends, fishing gear, and the like.

slightly soluble in dilute alcohol; insoluble in strong

alcohol.

Derivation: From nucleic acid hydrolyzates from

USAN. Abbreviation for United States Adopted

yeast. Radioactive forms available. Name, a nonproprietary name approved by the

Use: Biochemical research. American Pharmaceutical Association, American

1308USDA

Medical Association, and the U.S. Pharmacopeia. tional labeling of food products. They are based on

Such names applied to pharmaceutical products do the Recommended Dietary Allowances previously

not imply endorsement; their use in advertising and established by the Food and Nutrition Board, and the

labeling is required by law. National Research Council of the National Acade-

my of Sciences, and they are revised periodically.

See RDA.

USDA. Abbreviation for United States Depart-

ment of Agriculture.

UTP. See uridine phosphate.

USP. Abbreviation for United States Pharma-

copeia.

UV. See ultraviolet.

usnic acid. (usninic acid).

UVA. See ultraviolet.

CAS: 125-46-2. C

. A tricyclic compound. A

constituent of many lichens. Known in d, l, and dl

UVB. See ultraviolet.

forms.

Properties: Crystalline, yellow solid. Melting range

“UV-Chek” [Ferro]. TM for light stabilizers.

192–203C. Insoluble in water; slightly soluble in

alcohol and ether.

“Uvinul” [BASF]. TM for 2-ethylhexyl-2-cya-

Derivation: From Usnea barbata, a lichen growing

no-3

′

-diphenyl acrylate.

on trees.

Use: In sunscreen products.

Use: Medicine (antibiotic).

“Uvitex” [Novartis]. TM for a group of fluor-

USP. Abbreviation for United States Pharmacop-

escent whitening agents used on natural and synthet-

eia, the official publication for drug product stan-

ic textile fabrics and yarn.

dards.

USRDA. Abbreviation for United States Recom- 17-␣-uzarigenin.

mended Dietary Allowances for food and nutrition, CAS: 663-97-8. mf: C

established by the Food and Drug Administration Hazard: A poison.

(FDA) to serve as a basis for regulations on nutri- Source: Natural product.