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Benzene(CAS No. 71-43-2)

Benzene C6H6 (cas 71-43-2) Molecular Structure

71-43-2 Structure

Identification and Related Records

【Name】
Benzene
【CAS Registry number】
71-43-2
【Synonyms】
1,3,5-Cyclohexatriene
Benzol
Benzole
Coal naphtha
Cyclohexatriene
NSC 67315
Phene
Phenylhydride
Pyrobenzol
Pyrobenzole
[6]Annulene
【EINECS(EC#)】
200-753-7
【Molecular Formula】
C6H6 (Products with the same molecular formula)
【Molecular Weight】
78.11
【Inchi】
InChI=1S/C6H6/c1-2-4-6-5-3-1/h1-6H
【InChIKey】
UHOVQNZJYSORNB-UHFFFAOYSA-N
【Canonical SMILES】
C1=CC=CC=C1
【MOL File】
71-43-2.mol

Chemical and Physical Properties

【Appearance】
Clear liquid
【Density】
0.8786
【Melting Point】
6 C
【Boiling Point】
80 C
【Refractive Index】
1.5011
【Flash Point】
-11 oC
【Water】
0.18 G/100 ML
【Solubilities】
Slightly soluble
【Color/Form】
Clear, colorless liq
RHOMBIC PRISMS
Colorless to light-yellow liquid [Note: A solid below 42 degrees F].
【Stability】
Stable. Substances to be avoided include strong oxidizing agents, sulfuric acid, nitric acid, halogens. Highly flammable.
【Storage temp】
0-6°C
【Spectral properties】
MAX ABSORPTION (ALCOHOL): 243 NM (LOG E= 2.2), 249 NM (LOG E= 2.3), 256 NM (LOG E= 2.4), 261 NM (LOG E= 2.2); SADTLER REF NUMBER: 6402 (IR, PRISM), 1765 (UV)
Index of Refraction: 1.50108 @ 20 deg C/D
UV: 198 (Sadtler Research Laboratories Spectral Collection)
MASS: 102 (Atlas of Mass Spectral Data, John Wiley & Sons, New York)
IR: 136 (Sadtler Research Laboratories IR Grating Collection)
NMR: 3429 (Sadtler Research Laboratories Spectral Collection)
Intense mass spectral peaks: 78 m/z
【Computed Properties】
Molecular Weight:78.11184 [g/mol]
Molecular Formula:C6H6
XLogP3:2.1
H-Bond Donor:0
H-Bond Acceptor:0
Rotatable Bond Count:0
Exact Mass:78.04695
MonoIsotopic Mass:78.04695
Topological Polar Surface Area:0
Heavy Atom Count:6
Formal Charge:0
Complexity:15.5
Isotope Atom Count:0
Defined Atom Stereocenter Count:0
Undefined Atom Stereocenter Count:0
Defined Bond Stereocenter Count:0
Undefined Bond Stereocenter Count:0
Covalently-Bonded Unit Count:1
Feature 3D Ring Count:1
Effective Rotor Count:0
Conformer Sampling RMSD:0.4
CID Conformer Count:1

Safety and Handling

【Hazard Codes】
F: Flammable;T: Toxic;
【Risk Statements】
R45;R46;R11;R36/38;R48/23/24/25;R65
【Safety Statements 】
S53;S45
【HazardClass】
3
【Safety】

Hazard Codes:?FlammableF,ToxicT
Risk Statements: 45-46-11-36/38-48/23/24/25-65-39/23/24/25-23/24/25?
R45:May cause cancer.?
R46:May cause heritable genetic damage.?
R11:Highly flammable.?
R36/38:Irritating to eyes and skin.?
R39:Danger of very serious irreversible effects.??
R23/24/25:Toxic by inhalation, in contact with skin and if swallowed.?
R65:Harmful: may cause lung damage if swallowed.?
R48:Danger of serious damage to health by prolonged exposure.
Safety Statements: 53-45-36/37?
S53:Avoid exposure - obtain special instructions before use.?
S45:In case of accident or if you feel unwell, seek medical advice immediately (show the label whenever possible.)?
S36/37:Wear suitable protective clothing and gloves.
RIDADR: UN 1114 3/PG 2
WGK Germany: 3
RTECS: CY1400000

【PackingGroup 】
II
【Skin, Eye, and Respiratory Irritations】
Benzene is irritant to skin.
A severe eye and moderate skin irritant.
Skin irritation has been noted at occupational exposures of greater than 60 ppm for up to three weeks.
【Cleanup Methods】
For spills on water, contain with booms or barriers, use surface acting agents to thicken spilled materials. Remove trapped materials with suction hoses.
Small spills of benzene can be taken up by sorption on carbon or synthetic sorbent resins. Flush area with water. For large quantities, if response is rapid, benzene can be skimmed off the surface. Straw may be used to mop slicks.
PRECAUTIONS FOR "CARCINOGENS": A high-efficiency particulate arrestor (HEPA) or charcoal filters can be used to minimize amt of carcinogen in exhausted air ventilated safety cabinets, lab hoods, glove boxes or animal rooms. ... Filter housing that is designed so that used filters can be transferred into plastic bag without contaminating maintenance staff is avail commercially. Filters should be placed in plastic bags immediately after removal. ... The plastic bag should be sealed immediately. ... The sealed bag should be labelled properly. ... Waste liquids ... should be placed or collected in proper containers for disposal. The lid should be secured & the bottles properly labelled. Once filled, bottles should be placed in plastic bag, so that outer surface ... is not contaminated. ... The plastic bag should also be sealed & labelled. ... Broken glassware ... should be decontaminated by solvent extraction, by chemical destruction, or in specially designed incinerators. /Chemical Carcinogens/
Eliminate all ignition sources. Stop or control the leak, if this can be done without undue risk. Use water spray to cool and disperse vapors, protect personnel, and dilute spills to form nonflammable mixtures. Absorb in noncombustible material for proper disposal. Control runoff and isolate discharged material for proper disposal.
Environmental considerations - Air spill: Apply water spray or mist to knock down vapors.
Environmental considerations - Water spill: Use natural barriers or oil spill control booms to limit spill travel. Use surface active agent (e.g., detergent, soaps, alcohols), if approved by EPA. Inject "universal" gelling agent to solidify encircled spill and increase effectiveness of booms. If dissolved, in region of 10 ppm or grater concentration, apply activated carbon at ten times the spilled amount. Remove trapped material with suction hoses. Use mechanical dredges or lifts to remove immobilized masses of pollutants and precipitates.
Environmental considerations - Land spill: Dig a pit, lagoon, holding area to contain liquid or solid material. /SRP: If time permits, pits, ponds, lagoons, soak holes, or holding areas should be sealed with an impermeable flexible membrane liner./ Dike surface flow using soil, sand bags, foamed polyurethane, or foamed concrete. Absorb bulk liquid with fly ash, cement powder, or commercial sorbents. Apply appropriate foam to diminish vapor and fire hazard.
【Transport】
UN 1114/1115
【Fire Fighting Procedures】
Approach fire from upwind to avoid hazardous vapors. Use water spray, dry chemical, foam, or carbon dioxide. Use water spray to keep fire-exposed containers cool.
If material on fire or involved in fire: Do not extinguish fire unless flow can be stopped or safely confined. Use water in flooding quantities as fog. Solid streams of water may spread fire. Cool all affected containers with flooding quantities of water. Apply water from as far a distance as possible. Use foam, dry chemical, or carbon dioxide.
【Fire Potential】
A dangerous fire hazard when exosed to heat or flame. ... Ignites on contact with sodium peroxide + water, dioxygenyl tetrafluoroborate, iodine heptafluoride, and dioxygen difluoride.
【Formulations/Preparations】
Nitration grade > 99% purity.
"Benzol 90" contains 80-85% benzene, 13-15% toluene, 2-3% xylene.
Commercial grades of benzene: Refined benzene-535 (free of H2S and SO2, 1 ppm max thiophene, 0.15% max nonaromatics); Refined benzene-485, Nitration-grade (free of H2S and SO2); Industrial-grade benzene (free of H2S and SO2)
Grade: crude, straw color; motor; industrial pure (2C); nitration (1C); thiophene-free; 99 mole%; 99.94 mole%; nanograde.
【DOT Emergency Guidelines】
/GUIDE 130: FLAMMABLE LIQUIDS (NON-POLAR/WATER-IMMISCIBLE/NOXIOUS)/ Fire or Explosion: HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames. Vapors may form explosive mixtures with air. Vapors may travel to source of ignition and flash back. Most vapors are heavier than air. They will spread along ground and collect in low or confined areas (sewers, basements, tanks). Vapor explosion hazard indoors, outdoors or in sewers. Runoff to sewer may create fire or explosion hazard. Containers may explode when heated. Many liquids are lighter than water.
/GUIDE 130: FLAMMABLE LIQUIDS (NON-POLAR/WATER-IMMISCIBLE/NOXIOUS)/ Health: May cause toxic effects if inhaled or absorbed through skin. Inhalation or contact with material may irritate or burn skin and eyes. Fire will produce irritating, corrosive and/or toxic gases. Vapors may cause dizziness or suffocation. Runoff from fire control or dilution water may cause pollution.
/GUIDE 130: FLAMMABLE LIQUIDS (NON-POLAR/WATER-IMMISCIBLE/NOXIOUS)/ Public Safety: CALL Emergency Response Telephone Number ... . As an immediate precautionary measure, isolate spill or leak area for at least 50 meters (150 feet) in all directions. Keep unauthorized personnel away. Stay upwind. Keep out of low areas. Ventilate closed spaces before entering.
/GUIDE 130: FLAMMABLE LIQUIDS (NON-POLAR/WATER-IMMISCIBLE/NOXIOUS)/ Protective Clothing: Wear positive pressure self-contained breathing apparatus (SCBA). Structural firefighters' protective clothing will only provide limited protection.
/GUIDE 130: FLAMMABLE LIQUIDS (NON-POLAR/WATER-IMMISCIBLE/NOXIOUS)/ Evacuation: Large spill: Consider initial downwind evacuation for at least 300 meters (1000 feet). Fire: If tank, rail car or tank truck is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions.
/GUIDE 130: FLAMMABLE LIQUIDS (NON-POLAR/WATER-IMMISCIBLE/NOXIOUS)/ Fire: CAUTION: All these products have a very low flash point: Use of water spray when fighting fire may be inefficient. Small fires: Dry chemical, CO2, water spray or regular foam. Large fires: Water spray, fog or regular foam. Do not use straight streams. Move containers from fire area if you can do it without risk. Fire involving tanks or car/trailer loads: Fight fire from maximum distance or use unmanned hose holders or monitor nozzles. Cool containers with flooding quantities of water until well after fire is out. Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank. ALWAYS stay away from tanks engulfed in fire. For massive fire, use unmanned hose holders or monitor nozzles; if this is impossible, withdraw from area and let fire burn.
/GUIDE 130: FLAMMABLE LIQUIDS (NON-POLAR/WATER-IMMISCIBLE/NOXIOUS)/ Spill or Leak: ELIMINATE all ignition sources (no smoking, flares, sparks or flames in immediate area). All equipment used when handling the product must be grounded. Do not touch or walk through spilled material. Stop leak if you can do it without risk. Prevent entry into waterways, sewers, basements or confined areas. A vapor suppressing foam may be used to reduce vapors. Absorb or cover with dry earth, sand or other non-combustible material and transfer to containers. Use clean non-sparking tools to collect absorbed material. Large spills: Dike far ahead of liquid spill for later disposal. Water spray may reduce vapor; but may not prevent ignition in closed spaces.
/GUIDE 130: FLAMMABLE LIQUIDS (NON-POLAR/WATER-IMMISCIBLE/NOXIOUS)/ First Aid: Move victim to fresh air. Call 911 or emergency medical service. Give artificial respiration if victim is not breathing. Administer oxygen if breathing is difficult. Remove and isolate contaminated clothing and shoes. In case of contact with substance, immediately flush skin or eyes with running water for at least 20 minutes. Wash skin with soap and water. Keep victim warm and quiet. In case of burns, immediately cool affected skin for as long as possible with cold water. Do not remove clothing if adhering to skin. Effects of exposure (inhalation, ingestion or skin contact) to substance may be delayed. Ensure that medical personnel are aware of the material(s) involved and take precautions to protect themselves.
【Exposure Standards and Regulations】
Benzene is an indirect food additive for use only as a component of adhesives.
【Reactivities and Incompatibilities】
Reacts violently with iodine pentafluoride.
Hydrogenation of benzene to cyclohexane was effected in a fixed bed reactor at 210-230 deg C, but a fall in conversion was apparent. Increasing the bed temp by 10 deg C & the hydrogen flow led to a large increase in reaction rate which the interbed cooling coils could not handle, & an exotherm to 280 deg C developed, with a hot spot around 600 deg C which bulged the reactor wall.
Benzene ... ignites in contact with /iodine heptafluoride/ gas ...
Dioxygenyl tetrafluoroborate is a very powerful oxidant, addition of a small particle to small samples of benzene ... at ambient temp ... /caused/ ignition.
... A 2% solution /dioxygen difluoride/ in hydrogen fluoride ignites solid benzene at -78 deg C.
Simultaneous contact of sodium peroxide with ... benzene ... causes ignition, (equivalent to contact with concn hydrogen peroxide).
Interaction /of uranium hexafluoride/ with benzene ... is very vigorous, with separation of carbon ...
Benzene ignites in contact with powdered chromic anhydride.
AN EXPLOSION OF BENZENE VAPORS & CHLORINE (INADVERTENTLY MIXED) WAS INITIATED BY LIGHT.
Reacts explosively with bromine pentafluoride, chlorine, chlorine trifluoride, diborane, nitric acid, nitryl perchlorate, oxygen (liquid), ozone, silver perchlorate.
Interaction of the pentafluoride & methoxide /from arsenic pentafluoride & potassium methoxide/ proceeded smoothly in trichlorotrifluoroethane at 30-40 deg C, whereas in benzene as solvent repeated explosions occurred.
The effects of the presence of moisture or benzene vapor in air on the spontaneously explosive reaction /of diborane/ have been studied.
Silver perchlorate forms solid complexes with aniline, pyridine, toluene, benzene & many other aromatic hydrocarbons. A sample of the benzene complex exploded violently on crushing in a mortar.
Interaction /of nitryl perchlorate/ with benzene gave a slight explosion & flash. ...
The solution of permanganic acid (or its explosive anhydride, dimanganese heptoxide) produced by interaction of permanganates & sulfuric acid, will explode on contact with benzene ... .
Large-scale addition of too-cold nitrating acid to benzene without agitation later caused an uncontrollably violent reaction to occur when stirring was started. The vapor-air mixture produced was ignited by interaction of benzene & nitric acid at 100-170 deg C & caused an extremely violent explosion.
Peroxodisulfuric acid ... /is/ a very powerful oxidant; uncontrolled contact with ... benzene ... may cause explosion.
Mixtures of /liquid oxygen &/ benzene are specifically described as explosive.
During ozonization of rubber dissolved in benzene, an explosion occurred. This seems unlikely to have been ... /due/ to formation of benzene triozonide (which separates as a gelatinous precipitate after prolonged ozonization), since the solution remained clear. A rubber ozonide may have been involved, but the benzene-oxygen system itself has high potential for hazard.
Mixtures /of peroxomonosulfuric acid/ with ... benzene ... explodes.
Certain metal perchlorates recrystallized from benzene or ethyl alcohol can explode spontaneously.
Strong oxidizers, many fluorides & perchlorates, nitric acid.
Vigorous or incandescent reaction with hydrogen + Raney nickel (above 210 deg C) ... and bromine trifluoride. Can react vigorously with oxidizing materials, such as ... CrO3, oxygen, NClO4, ozone, perchlorates, (AlCl3 + FClO4), (sulfuric acid + permanganates), K2O2, (AgClO4 + acetic acid) ...
Explodes on contact with diborane, bromine pentafluoride, permanganic acid, peroxomonosulfuric acid, and peroxodisulfuric acid. Forms sensitive, explosive mixtures with iodine pentafluoride, silver perchlorate, nitryl perchlorate, nitric acid, liquid oxygen, ozone, arsenic pentafluoride + potassium methoxide (explodes above 30 deg C). ... Moderate explosion hazard when exposed to heat or flame.
【Other Preventative Measures】
SRP: The scientific literature for the use of contact lenses in industry is conflicting. The benefit or detrimental effects of wearing contact lenses depend not only upon the substance, but also on factors including the form of the substance, characteristics and duration of the exposure, the uses of other eye protection equipment, and the hygiene of the lenses. However, there may be individual substances whose irritating or corrosive properties are such that the wearing of contact lenses would be harmful to the eye. In those specific cases, contact lenses should not be worn. In any event, the usual eye protection equipment should be worn even when contact lenses are in place.
SRP: Local exhaust ventilation should be applied wherever there is an incidence of point source emmissions or dispersion of regulated contaminants in the work area. Ventilation control of the contaminant as close to its point of generation is both the most economical and safest method to minimize personnel exposure to airborne contaminants.
VENTILATION CONTROL: WHEREVER POSSIBLE, PLANT SHOULD BE TOTALLY ENCLOSED ... ENCLOSURES SHOULD BE SUPPLEMENTED BY EXHAUST VENTILATION ... ATMOSPHERE ... SHOULD BE TESTED PERIODICALLY ...
PRECAUTIONS FOR "CARCINOGENS": Smoking, drinking, eating, storage of food or of food & beverage containers or utensils, & the application of cosmetics should be prohibited in any laboratory. All personnel should remove gloves, if worn, after completion of procedures in which carcinogens have been used. They should ... wash ... hands, preferably using dispensers of liq detergent, & rinse ... thoroughly. Consideration should be given to appropriate methods for cleaning the skin, depending on nature of the contaminant. No standard procedure can be recommended, but the use of organic solvents should be avoided. Safety pipettes should be used for all pipetting. /Chemical Carcinogens/
PRECAUTIONS FOR "CARCINOGENS": In animal laboratory, personnel should remove their outdoor clothes & wear protective suits (preferably disposable, one-piece & close-fitting at ankles & wrists), gloves, hair covering & overshoes. ... Clothing should be changed daily but ... discarded immediately if obvious contamination occurs ... /also,/ workers should shower immediately. In chemical laboratory, gloves & gowns should always be worn ... however, gloves should not be assumed to provide full protection. Carefully fitted masks or respirators may be necessary when working with particulates or gases, & disposable plastic aprons might provide addnl protection. If gowns are of distinctive color, this is a reminder that they should not be worn outside of lab. /Chemical Carcinogens/
PRECAUTIONS FOR "CARCINOGENS": ... Operations connected with synth & purification ... should be carried out under well-ventilated hood. Analytical procedures ... should be carried out with care & vapors evolved during ... procedures should be removed. ... Expert advice should be obtained before existing fume cupboards are used ... & when new fume cupboards are installed. It is desirable that there be means for decreasing the rate of air extraction, so that carcinogenic powders can be handled without ... powder being blown around the hood. Glove boxes should be kept under negative air pressure. Air changes should be adequate, so that concn of vapors of volatile carcinogens will not occur. /Chemical Carcinogens/
PRECAUTIONS FOR "CARCINOGENS": Vertical laminar-flow biological safety cabinets may be used for containment of in vitro procedures ... provided that the exhaust air flow is sufficient to provide an inward air flow at the face opening of the cabinet, & contaminated air plenums that are under positive pressure are leak-tight. Horizontal laminar-flow hoods or safety cabinets, where filtered air is blown across the working area towards the operator, should never be used ... Each cabinet or fume cupboard to be used ... should be tested before work is begun (eg, with fume bomb) & label fixed to it, giving date of test & avg air-flow measured. This test should be repeated periodically & after any structural changes. /Chemical Carcinogens/
PRECAUTIONS FOR "CARCINOGENS": Principles that apply to chem or biochem lab also apply to microbiological & cell-culture labs. ... Special consideration should be given to route of admin. ... Safest method of administering volatile carcinogen is by injection of a soln. Admin by topical application, gavage, or intratracheal instillation should be performed under hood. If chem will be exhaled, animals should be kept under hood during this period. Inhalation exposure requires special equipment. ... Unless specifically required, routes of admin other than in the diet should be used. Mixing of carcinogen in diet should be carried out in sealed mixers under fume hood, from which the exhaust is fitted with an efficient particulate filter. Techniques for cleaning mixer & hood should be devised before expt begun. When mixing diets, special protective clothing &, possibly, respirators may be required. /Chemical Carcinogens/
PRECAUTIONS FOR "CARCINOGENS": When ... admin in diet or applied to skin, animals should be kept in cages with solid bottoms & sides & fitted with a filter top. When volatile carcinogens are given, filter tops should not be used. Cages which have been used to house animals that received carcinogens should be decontaminated. Cage-cleaning facilities should be installed in area in which carcinogens are being used, to avoid moving of ... contaminated /cages/. It is difficult to ensure that cages are decontaminated, & monitoring methods are necessary. Situations may exist in which the use of disposable cages should be recommended, depending on type & amt of carcinogen & efficiency with which it can be removed. /Chemical Carcinogens/
PRECAUTIONS FOR "CARCINOGENS": To eliminate risk that ... contamination in lab could build up during conduct of expt, periodic checks should be carried out on lab atmospheres, surfaces, such as walls, floors & benches, & ... interior of fume hoods & airducts. As well as regular monitoring, check must be carried out after cleaning-up of spillage. Sensitive methods are required when testing lab atmospheres for chem such as nitrosamines. Methods ... should ... where possible, be simple & sensitive. ... /Chemical Carcinogens/
PRECAUTIONS FOR "CARCINOGENS": Rooms in which obvious contamination has occurred, such as spillage, should be decontaminated by lab personnel engaged in expt. Design of expt should ... avoid contamination of permanent equipment. ... Procedures should ensure that maintenance workers are not exposed to carcinogens. ... Particular care should be taken to avoid contamination of drains or ventilation ducts. In cleaning labs, procedures should be used which do not produce aerosols or dispersal of dust, ie, wet mop or vacuum cleaner equipped with high-efficiency particulate filter on exhaust, which are avail commercially, should be used. Sweeping, brushing & use of dry dusters or mops should be prohibited. Grossly contaminated cleaning materials should not be re-used. ... If gowns or towels are contaminated, they should not be sent to laundry, but ... decontaminated or burnt, to avoid any hazard to laundry personnel. /Chemical Carcinogens/
PRECAUTIONS FOR "CARCINOGENS": Doors leading into areas where carcinogens are used ... should be marked distinctively with appropriate labels. Access ... limited to persons involved in expt. ... A prominently displayed notice should give the name of the Scientific Investigator or other person who can advise in an emergency & who can inform others (such as firemen) on the handling of carcinogenic substances. /Chemical Carcinogens/
SRP: Contaminated protective clothing should be segregated in such a manner so that there is no direct personal contact by personnel who handle, dispose, or clean the clothing. Quality assurance to ascertain the completeness of the cleaning procedures should be implemented before the decontaminated protective clothing is returned for reuse by the workers.
The worker should immediately wash the skin when it becomes contaminated.
Work clothing that becomes wet should be immediately removed due to its flammability hazard.
Evacuation: If material leaking (not on fire) consider evacuation from downwind area based on amount of material spilled, location and weather conditions.
Personnel protection: Avoid breathing vapors. Keep upwind. ... Do not handle broken packages unless wearing appropriate personal protective equipment. Wash away any material which may have contacted the body with copious amounts of water or soap and water.
If material not on fire and not involved in fire: Keep sparks, flames, and other sources of ignition away. Keep material out of water sources and sewers. Build dikes to contain flow as necessary. Attempt to stop leak if without undue personnel hazard. Use water spray to knock-down vapors.
【Protective Equipment and Clothing】
Protective clothing consisting of coveralls or other full body clothing should be worn and changed at least twice weekly.
Where there is a possibility of benzene contact to eyes or skin, safety showers, eye-wash fountains, and cleansing facilities shall be installed and maintained.
WHERE HIGH VAPOR CONCN ARE UNAVOIDABLE, FORCED AIR MASKS SHOULD BE USED. LIFELINE ATTENDED BY ... PERSON OUTSIDE CONTAMINATED ENCLOSURE IS MANDATORY. IF SKIN CONTACT IS UNAVOIDABLE, NEOPRENE GLOVES MUST BE WORN.
HYDROCARBON VAPOR CANISTER, SUPPLIED AIR OR A HOSE MASK; HYDROCARBON INSOLUBLE RUBBER OR PLASTIC GLOVES; CHEMICAL GOGGLES OR FACE SPLASH SHIELD; HYDROCARBON-INSOLUBLE APRON SUCH AS NEOPRENE.
PRECAUTIONS FOR "CARCINOGENS": ... Dispensers of liq detergent /should be available./ ... Safety pipettes should be used for all pipetting. ... In animal laboratory, personnel should ... wear protective suits (preferably disposable, one-piece & close-fitting at ankles & wrists), gloves, hair covering & overshoes. ... In chemical laboratory, gloves & gowns should always be worn ... however, gloves should not be assumed to provide full protection. Carefully fitted masks or respirators may be necessary when working with particulates or gases, & disposable plastic aprons might provide addnl protection. ... Gowns ... /should be/ of distinctive color, this is a reminder that they are not to be worn outside the laboratory. /Chemical Carcinogens/
Performance data: For butyl rubber, natural rubber, neoprene, neoprene, neoprene/natural rubber, nitrile rubber, polyethylene, chlorinated polyethylene, polyurethane, and polyvinyl chloride give breakthrough times less (usually significantly less) than one hour reported by (normally) two or more testers. Vendor Recommendations: C or D ratings from three or more (apparently independent) vendors.
Wear appropriate personal protective clothing to prevent skin contact.
Wear appropriate eye protection to prevent eye contact.
Eyewash fountains should be provided in areas where there is any possibility that workers could be exposed to the substance; this is irrespective of the recommendation involving the wearing of eye protection.
Facilities for quickly drenching the body should be provided within the immediate work area for emergency use where there is a possibility of exposure. [Note: It is intended that these facilities should provide a sufficient quantity or flow of water to quickly remove the substance from any body areas likely to be exposed. The actual determination of what constitutes an adequate quick drench facility depends on the specific circumstances. In certain instances, a deluge shower should be readily available, whereas in others, the availability of water from a sink or hose could be considered adequate.]
Recommendations for respirator selection. Condition: At concentrations above the NIOSH REL, or where there is no REL, at any detectable concentration. Respirator Class(es): Any self-contained breathing apparatus that has a full facepiece and is operated in a pressure-demand or other positive pressure mode. Any supplied-air respirator that has a full face piece and is operated in pressure-demand or other positive pressure mode in combination with an auxiliary self-contained breathing apparatus operated in pressure-demand or other positive pressure mode.
Recommendations for respirator selection. Condition: Escape from suddenly occurring respiratory hazards: Respirator Class(es): Any air-purifying, full-facepiece respirator (gas mask) with a chin-style, front- or back-mounted organic vapor canister. Any appropriate escape-type, self-contained breathing apparatus.
【Specification】

? Benzene (CAS NO.71-43-2), its Synonyms are (6)Annulene ; Benzin ; Benzin (Obs.) ; Benzine ; Coal naphtha ; Cyclohexatriene ; Mineral naphtha ; Motor benzol ; Phenyl hydride ; Polystream . Benzene is a colorless and highly flammable liquid with a sweet smell and a relatively high melting point.

【Octanol/Water Partition Coefficient】
log Kow= 2.13
【Disposal Methods】
Generators of waste (equal to or greater than 100 kg/mo) containing this contaminant, EPA hazardous waste number F005, must conform with USEPA regulations in storage, transportation, treatment and disposal of waste.
Generators of waste (equal to or greater than 100 kg/mo) containing this contaminant, EPA hazardous waste number U019, must conform with USEPA regulations in storage, transportation, treatment and disposal of waste.
Generators of waste (equal to or greater than 100 kg/mo) containing this contaminant, EPA hazardous waste number D018, must conform with USEPA regulations in storage, transportation, treatment and disposal of waste.
Biodegradation, incineration: Benzene is biodegradable. Diluted aqueous soln, therefore, are drained into sewage treatment plants and decomposed there by anaerobic bacteria. Solvent mixtures and sludges of higher concn are burnt in special waste incinerators if a recovery process is uneconomical.
This flammable liquid burns with a very smoky flame. Dilution with alcohol or acetone is suggested to minimize smoke. Recommendable methods: Use as boiler fuel, incineration. Not recommendable: Landfill, discharge to sewer.
Incinerate or dispose of via a licensed solvent recycling or disposal company.
PRECAUTIONS FOR "CARCINOGENS": There is no universal method of disposal that has been proved satisfactory for all carcinogenic compounds & specific methods of chem destruction ... published have not been tested on all kinds of carcinogen-containing waste. ... Summary of avail methods & recommendations ... /given/ must be treated as guide only. /Chemical Carcinogens/
PRECAUTIONS FOR "CARCINOGENS": Total destruction ... by incineration may be only feasible method for disposal of contaminated laboratory waste from biological expt. However, not all incinerators are suitable for this purpose. The most efficient type ... is probably the gas-fired type, in which a first-stage combustion with a less than stoichiometric air:fuel ratio is followed by a second stage with excess air. Some ... are designed to accept ... aqueous & organic-solvent solutions, otherwise it is necessary ... to absorb soln onto suitable combustible material, such as sawdust. Alternatively, chem destruction may be used, esp when small quantities ... are to be destroyed in laboratory. /Chemical Carcinogens/
PRECAUTIONS FOR "CARCINOGENS": HEPA (high-efficiency particulate arrestor) filters ... can be disposed of by incineration. For spent charcoal filters, the adsorbed material can be stripped off at high temp & carcinogenic wastes generated by this treatment conducted to & burned in an incinerator. ... LIQUID WASTE: ... Disposal should be carried out by incineration at temp that ... ensure complete combustion. SOLID WASTE: Carcasses of lab animals, cage litter & misc solid wastes ... should be disposed of by incineration at temp high enough to ensure destruction of chem carcinogens or their metabolites. /Chemical Carcinogens/
PRECAUTIONS FOR "CARCINOGENS": ... Small quantities of ... some carcinogens can be destroyed using chem reactions ... but no general rules can be given. ... As a general technique ... treatment with sodium dichromate in strong sulfuric acid can be used. The time necessary for destruction ... is seldom known ... but 1-2 days is generally considered sufficient when freshly prepd reagent is used. ... Carcinogens that are easily oxidizable can be destroyed with milder oxidative agents, such as sat soln of potassium permanganate in acetone, which appears to be a suitable agent for destruction of hydrazines or of compounds containing isolated carbon-carbon double bonds. Concn or 50% aqueous sodium hypochlorite can also be used as an oxidizing agent. /Chemical Carcinogens/
PRECAUTIONS FOR "CARCINOGENS": Carcinogens that are alkylating, arylating or acylating agents per se can be destroyed by reaction with appropriate nucleophiles, such as water, hydroxyl ions, ammonia, thiols & thiosulfate. The reactivity of various alkylating agents varies greatly ... & is also influenced by sol of agent in the reaction medium. To facilitate the complete reaction, it is suggested that the agents be dissolved in ethanol or similar solvents. ... No method should be applied ... until it has been thoroughly tested for its effectiveness & safety on material to be inactivated. For example, in case of destruction of alkylating agents, it is possible to detect residual compounds by reaction with 4(4-nitrobenzyl)-pyridine. /Chemical Carcinogens/
Chemical Treatability of Benzene; Concentration Process: Biological Treatment; Chemical Classification: Aromatic; Scale of Study: Full Scale; Type of Wastewater Used: Industrial Wastewater; Results of Study: 90-100% reduction; (treated by aerated lagoon).
Chemical Treatability of Benzene; Concentration Process: Biological Treatment; Chemical Classification: Aromatic; Scale of Study: Full Scale; Type of Wastewater Used: Industrial Wastewater; Results of Study: 95-100% reduction; (completely mixed activated sludge process).
Chemical Treatability of Benzene; Concentration Process: Biological Treatment; Chemical Classification: Aromatic; Scale of Study: Respirometer Study; Type of Wastewater Used: Domestic Wastewater; Results of Study: 1.44-1.45 g of oxygen utilized/g of substrate added after 72 hr of oxidation.
Chemical Treatability of Benzene; Concentration Process: Biological Treatment; Chemical Classification: Aromatic; Scale of Study: Respirometer Study; Type of Wastewater Used: Domestic Wastewater; Results of Study: Oxygen uptake of 34 ppm oxygen/hr for 50 ppm chemical and 37 ppm oxygen/hr for 500 ppm chemical.
Chemical Treatability of Benzene; Concentration Process: Biological Treatment; Chemical Classification: Aromatic; Scale of Study: Full Scale; Type of Wastewater Used: Industrial Wastewater; Results of Study: 95-100% reduction; (Activated sludge process).
Chemical Treatability of Benzene; Concentration Process: Stripping; Chemical Classification: Aromatic; Scale of Study: Literature Review; Type of Wastewater Used: Unknown; Results of Study: Air and steam strippable.
Chemical Treatability of Benzene; Concentration Process: Stripping; Chemical Classification: Aromatic; Scale of Study: Continuous Flow, Pilot Scale; Type of Wastewater Used: Synthetic Wastewater; Results of Study: 95-99% reduction by steam stripping; (estimated cost of $3.35/1000 gal based on 0.03 MGD).
Chemical Treatability of Benzene; Concentration Process: Solvent Extraction; Chemical Classification: Aromatic; Scale of Study: Literature Review; Type of Wastewater Used: Unknown; Results of Study: Extractable with suitable solvent.
Chemical Treatability of Benzene; Concentration Process: Solvent Extraction; Chemical Classification: Aromatic; Scale of Study: Laboratory Scale, Continuous Flow; Type of Wastewater Used: Industrial Wastewater; Results of Study: 290 ppm @ 3 gal/hr, 97% reduction; (Extraction of wastewater from styrene manufacture using isobutylane (S/W= 0.107), RDC extractor used).
Chemical Treatability of Benzene; Concentration Process: Solvent Extraction; Chemical Classification: Aromatic; Scale of Study: Laboratory Scale, Continuous Flow; Type of Wastewater Used: Industrial Wastewater; Results of Study: 71 ppm @ 4.6 gal/hr, 96% reduction; (extraction of ethylene quench wastewater using isobutylene (S/W= 0.101) RDC extractor used).
Chemical Treatability of Benzene; Concentration Process: Solvent Extraction; Chemical Classification: Aromatic; Scale of Study: Laboratory Scale, Continuous Flow; Type of Wastewater Used: Industrial Waste; Results of Study: 81 ppm @ 4.6 gal/hr, 97% reduction; (extraction of ethylene quench wastewater using isobutane (S/W= 0.097) RDC extractor used).
Chemical Treatability of Benzene; Concentration Process: Activated Carbon; Chemical Classification: Aromatic; Scale of Study: Pilot Scale, Continuous Flow; Type of Wastewater Used: Hazardous Material Spill Results of Study: 90% removal (to 0.1 ppb effluent conc) achieved in 8.5 min contact time; (Spilled material treated using EPA's mobile treatment trailer).
Chemical Treatability of Benzene; Concentration Process: Activated Carbon; Chemical Classification: Aromatic; Scale of Study: Isotherm Test; Type of Wastewater Used: Pure Compound; Results of Study: 0.7 mg/g carbon capacity.
Chemical Treatability of Benzene; Concentration Process: Activated Carbon; Chemical Classification: Aromatic; Scale of Study: Isotherm Test; Type of Wastewater Used: Pure Compound; Results of Study: Isotherm kinetics were as follows: Carbon: K= 26.8, l/n= 1.305; Filtrasorb: K= 18.5 l/n= 1.158; carbon dose (mg/l) required to reduce 1 mg/l to 0.1 mg/l; Daro-678 Filtrasorb-705.
Chemical Treatability of Benzene; Concentration Process: Activated Carbon; Chemical Classification: Aromatic; Scale of Study: Isotherm Test; Type of Wastewater Used: Pure Compound; Results of Study: 95% reduction, 21 ppm final concn, 0.080 g/g carbon capacity; (Carbon dose with 5 g/l Westvaco Nuchar).
Chemical Treatability of Benzene; Concentration Process: Activated Carbon; Chemical Classification: Aromatic; Scale of Study: Literature Review; Type of Wastewater Used: Industrial Wastewater; Results of Study: Effluent concn of 30 ppm TOC achieved; 98% removal; (at contact time of 55 min 0.15 MGD flow; pretreatment including pH adjustment).
Chemical Treatability of Benzene; Concentration Process: Activated Carbon; Chemical Classification: Aromatic; Scale of Study: Isotherm Test; Type of Wastewater Used: Pure Compound; Results of Study: Effluent Character (ppm): 500, 95% removal; 250, 91% removal; 50, 60% removal; (24 hr contact time, carbon dose was 10 times chemical concn).
Chemical Treatability of Benzene; Concentration Process: Activated Carbon; Chemical Classification: Aromatic; Scale of Study: Literature Review; Type of Wastewater Used: Unknown; Results of Study: 95% removal at 0.5% carbon dose.
A good candidate for liquid injection incineration at a temperature range of 650 to 1,600 deg C and a residence time of 0.1 to 2 seconds. A good candidate for rotary kiln incineration at a temperature range of 820 to 1,600 deg C and residence times of seconds for liquids and gases, and hours for solids. A good candidate for fluidized bed incineration at a temperature range of 450 to 980 deg C and residence times of seconds for liquids and gases, and longer for solids.
Full-scale activated carbon column treatment: Influent concn: 28,000 ug/l; Effluent concn: 1)

Use and Manufacturing

【Use and Manufacturing】
Methods of Manufacturing

Worldwide, approximately 30% of commercial benzene is produced by catalytic reforming, a process in which aromatic molecules are produced from the dehydrogenation of cycloparaffins, dehydroisomerization of alkyl cyclopentanes, and cyclization and subsequent dehydrogenation of paraffins. The benzene product is most often recovered from the reformate by solvent extraction techniques.
The production of benzene by reforming-separation processes is assoc with the production of toluene and xylene (BTX plants). The relative production of the various aromatic hydrocarbons is a function of the feedstock, reactor conditions, catalyst, and, primarily, of the boiling range of the prod fraction subjected to solvent extraction. ... In reforming processes, cycloparaffins, such as cyclohexane, methylcyclohexane, and dimethylcyclohexanes are converted to benzene by dehydrogenation or by dehydrogenation and dealkylation, and methylcyclopentane and dimethylcyclpentanes are converted to benzene by isomerization, dehydrogenation, and dealkylation. Straight-chain paraffins such as hexane are converted to benzene by cyclodehydrogenation. The process conditions & the catalyst determine which reaction predominate and their kinetics (Hydrocarbon Process 55 (9): 171-8 (1976); and P Bonnifay and co-workers, Oil Gas J 74 (3): 48 (1976)).
Two molecules of toluene are converted into one molecule of benzene and one molecule of mixed xylene isomers in a sequence called transalkylation or disproportionation. Economic feasibility of the process strongly depends on the relative prices of benzene, toluene, and xylene. Operation of a transalkylation unit is practical only when there is an excess of toluene and a strong demand for benzene. In recent years, xylene and benzene prices have generally been higher than toluene prices so transalkylation is presently an attractive alternative to hydrodealkylation.
Benzene has been recovered from coal tar. The lowest boiling fraction is extracted with caustic soda to remove tar acids. The base washed oil is then distilled and further purified by hydrodealkylation.
Benzene is produced from the hydrodemethylation of toluene under catalytic or thermal conditions. The main catalytic hydrodealkylation processes are Hydeal and DETOL. Two widely used thermal processes are HDA and THD. These processes contribute 25-30% of the world's total benzene supply.
The steam cracking of heavy naphthas or light hydrocarbons such as propane or butane to produce ethylene yields a liquid by-product rich in aromatic content called pyrolysis gasoline, dripolene, or drip oil. A typical pyrolysis gasoline contains up to about 65% aromatics, about 50% of which is benzene. Approximately 30-35% of benzene produced worldwide is derived from pyrolysis gasoline.
Purification by washing with water: British patent 863,711 (1961 to Schloven-Chemie and Koppers gmbh), Chem Abstr 55: 16971f (1961). Lab prepn from aniline: Gattermann-Wieland, Praxis des Organischen Chemikers (de Gruyter, Berlin, 40th ed: 247 (1961)).
U.S. Exports

(1978) 1.52X10+11 G
(1983) 3.66X10+10 G
(1979) 1.3 million lb
(1985) 3.77X10+10 g
Exports were thought to be less than 10 million gallons.
U.S. Imports

(1978) 2.26X10+11 G
(1979) 1.6 billion kg
(1983) 4.93X10+11 G
(1985) 4.96X10+11 g
(1986) 4.72X10+11 g
(1986) 1.56X10+8 lb
Imports in 1987 were estimated to total 175 million gallons.
U.S. Production

(1967) 9.6X10+8 gal (data reported by tar distillers are not included)
(1977) 4.80X10+12 G
(1980) 1.5X10+9 gal (data reported by tar distillers are not included)
(1981) 4.3X10+11 GRAMS
(1981) 1.3X10+9 gal (all grades produced from light-oil distillates of tar and tar crudes)
(1982) 3.55X10+12 G
(1983) 1.227X10+8 gallons
(1984) 1.312X10+8 gallons
(1988) 1.776X10+8 gallons (from petroleum), 5.25X10+7 gallons (from coal)
(1985) 3.74X10+9 g (98-100% pure from petroleum and natural gas)
(1985) 5.16X10+8 g (90-97.9% pure from petroleum and natural gas)
(1986) 4.39X10+11 g
(1986) 1.39X10+9 gal
(1987) 1.59X10+9 gal (est)
(1989) 5,414,072,000 kg (all grades)
Benzene ranks 16th in production volume for chemicals produced in the USA, with approx 9.9 billion lb being produced in 1984, 9.1 billion lb in 1983, and 7.8 billion lb in 1982.
(1990) 12.45 billion lb
(1991) 11.49 billion lb
(1992) 11.27 billion lb
(1993) 12.32 billion lb
Consumption Patterns

Consumption by chemical industry in USA, 1977: 1.4 billion gallons annually.
CHEM INT FOR ETHYLBENZENE, 49.1%; CHEM INT FOR CUMENE, 18.4%; CHEM INT FOR CYCLOHEXANE, 15.1%; CHEM INT FOR NITROBENZENE, 4.5%; CHEM INT FOR MALEIC ANHYDRIDE, 2.8%; CHEM INT FOR CHLOROBENZENES, 2.5%; CHEM INT FOR DETERGENT ALKYLATE, 2.4%; EXPORTS, 2.7%; OTHER USES, 2.5% (1981 NON-GASOLINE USES)
Demand: (1980) 1,586 Million Gal; /Projected demand for/ (1984): 1,708 Million Gal
BENZENE RANKED 17TH IN 1981 & 1982 IN THE TOP 50 CHEMICAL PRODUCTION: BILLIONS OF LB: 7.87 (1982), 9.61 (1981).
Ethylbenzene/styrene, 52%; cumene/phenol, 22%; clyclohexane, 15%; nitrobenzene/aniline, 4.5%; detergent alkylate, 2.5%; chlorobenzenes, maleic anhydride and other, 3%; exports, 1% (1984)
USA benzene demand /is projected to/ climb /from/ 3.8% in 1987, to 5.7 million tons, and reach 6 million tons in 1990 (1987 and 1990)
In future, coal will increasingly replace petroleum and natural gas as a source of hydrocarbons both for fuel and petrochemicals. Processes such as USA Steel Corporation's Clean Coke process, which yields 38% coke and 20% chemical by-products compared to 73% coke and 2% chemical by-products in conventional coking technology, should soon be used commercially. New coking, liquefaction, and gasification processes for coal are all potential sources of benzene.
CHEMICAL PROFILE: Benzene. Ethylbenzene/styrene, 55%; cumene/phenol, 21%; cyclohexane, 14%; nitrobenzene/aniline, 5%; detergent alkylate, 3%; chlorobenzenes, exports and others, 2%.
CHEMICAL PROFILE: Benzene. Demand: 1986: 1,603 million gal; 1987: 1,667 million gal; 1991 /projected/: 1,790 million gal. (Includes imports; 155 million gal were imported in 1986.)
World benzene production rose to 6X10+6 tons (1.8X10+9 gallons) in 1988. The United States is the largest producer of benzene and accounts for about 30% of world production.
U.S. demand: 2,000 million gallons in 1995; 1,900 million gallons 1996; predicted 2,100 million gallons 2000.
【Sampling Procedures】
ANALYTE: BENZENE; MATRIX: AIR; RANGE: 13 TO 51.8 PPM; PROCEDURE: ADSORPTION ON CHARCOAL, DESORPTION WITH CARBON DISULFIDE, GC. PRECISION: COEFFICIENT OF VARIATION 0.059 FOR TOTAL ANALYTICAL & SAMPLING METHOD IN RANGE OF 13 TO 51.8 PPM.
Analyte: Benzene by portable GC; Matrix: air; Sampler: air bag (Tedlar); Flow rate: 0.02 to 0.05 l/min or higher; Stability: approx 4 hr
Analyte: Benzene; Matrix: air; Sampler: Solid sorbent tube (coconut shell charcoal, 100 mg/50 mg); Flow rate: approx 0.20 l/min; Vol: max: 30 l; Stability: at least 2 wk; Bulk sample: 1 to 10 ml, ship in separate containers from samples.
Analyte; Benzene; Matrix: air; Sampler: Solid sorbent tube (coconut shell charcoal, 100 mg/50 mg); Flow rate: approx 0.20 l/min; Vol: max: 30 l; Stability: not determined; Bulk sample: 1 to 10 ml, ship in separate containers from samples.

Biomedical Effects and Toxicity

【Pharmacological Action】
Dizziness, excitation, pallor, followed by flushing, weakness, headache, breathlessness, chest constriction, nausea, and vomiting. Coma and possible death.
【Therapeutic Uses】
MEDICATION (VET): HAS BEEN USED AS A DISINFECTANT. /FORMER USE/
【Biomedical Effects and Toxicity】
BENZENE IS READILY ABSORBED VIA LUNG, & ABOUT 40-50% IS RETAINED. ... IT IS TAKEN UP PREFERENTIALLY BY FATTY & NERVOUS TISSUES, & ABOUT 30-50% ... IS EXCRETED UNCHANGED VIA LUNG; A 3-PHASE EXCRETION PATTERN IS SEEN AT ... /APPROX/ 0.7-1.7 HR, 3-4 HR, & 20-30 HR.
When benzene was placed on skin under closed cup it was absorbed at rate of 0.4 mg/sq cm/hr (Hanke et al 1961) ...
MICE TREATED SC WITH 2 ML (3)H-LABELED BENZENE/KG CONTAINED IRREVERSIBLY BOUND RADIOACTIVITY WITH DECREASING BINDING MAGNITUDE IN THE FOLLOWING ORGANS: LIVER, BRAIN, KIDNEY, SPLEEN, FAT. MICE TREATED WITH 2 DAILY SC DOSES OF 0.5 ML (3)H-BENZENE/KG FOR 1-10 DAYS SHOWED A RADIOACTIVITY BINDING WITH LIVER & BONE MARROW RESIDUES WHICH INCREASED WITH TREATMENT DURATION, EXCEPT IN THE CASE OF BINDING TO BONE MARROW WHICH DECREASED AFTER DAY 6. [SNYDER R ET AL; RES COMMUN CHEM PATHOL PHARMACOL 20 (1): 191-4 (1978)] PubMed Abstract
When administered to mice subcutaneously, 72% of dose is recovered in expired air. [Andrews LS et al; Biochem Pharmacol 26: 293 (1977)] PubMed Abstract
Rats were exposed to 500 ppm benzene for 30 min to eight hr. Benzene concentrations reached steady state within four hr in blood (steady-state concn= 11.5 ug/g), six hr in fat (concn= 164.4 ug/g), and two hr in bone marrow (concn= 37.0 ug/g). Lesser concn were detected in the kidney, lung, liver, brain, and spleen. [Rickert DE et al; Toxicol Appl Pharmacol 49: 417-23 (1979)] PubMed Abstract
Benzene is absorbed from the gastrointestinal tract when ingested.
BENZENE CROSSES THE HUMAN PLACENTA, & LEVELS IN CORD BLOOD ARE SIMILAR TO THOSE IN MATERNAL BLOOD. ... THE MOST FREQUENT ROUTE BY WHICH HUMANS ARE EXPOSED TO BENZENE IS VIA INHALATION. TOXIC EFFECTS IN HUMANS HAVE BEEN ATTRIBUTED TO COMBINED EXPOSURE BY BOTH RESPIRATION & THROUGH THE SKIN ... IT IS ELIMINATED UNCHANGED IN EXPIRED AIR ... IN MEN & WOMEN EXPOSED TO 52-62 PPM (166-198 MG/CU M) BENZENE FOR 4 HR, A MEAN OF 46.9% WAS TAKEN UP, 30.2% WAS RETAINED & THE REMAINING 16.8% EXCRETED AS UNCHANGED BENZENE IN EXPIRED AIR. ... WHEN HUMANS WERE EXPOSED TO 100 PPM (300 MG/CU M) BENZENE, IT WAS DETECTED IN EXPIRED AIR 24 HR LATER, SUGGESTING THAT IT IS POSSIBLE TO BACK-EXTRAPOLATE TO THE BENZENE CONCENTRATION IN THE INSPIRED AIR.
... In female & male rats with large body fat content, benzene was eliminated more slowly & stored longer than in lean animals. ... Distribution in rabbit was highest in adipose tissue, high for bone marrow, & lower for brain, heart, kidney, lung, & muscle, although direct binding was higher in liver than in bone marrow.
The solubility characteristics of benzene are such that it is easily taken up by the stratum corneum. Once in the stratum corneum, it does not meet many restraining forces to impede its movement and diffuses easily. The permeability constant for benzene, as determined in vitro, is higher than that of many other small molecules, particularly those having one or more polar groups. ... Even though these uncertainties exist, and more data are needed to support the ... conclusion that there is good overall agreement between in vitro and in vivo data. ... An adult working in ambient air containing 10 ppm of benzene, with 100 cm of glaborous skin in contact with gasoline containing 5% benzene, and his entire skin (2 sq m) in contact with ambient air, will absorb in an hr, 7.5 ul of benzene from inhalation, 7.0 ul from contact with gasoline, and 1.5 ul from body exposure to ambient air. Since ... in vitro techniques measure the penetration of benzene through strongly hydrated stratum corneum, the calculated flux may be higher than under some in vivo conditions. Nevertheless, it seems that unless good hygiene is maintained and care is taken to prevent lengthy exposure to solvents containing benzene, significant amounts of benzene may enter the body through the skin.
Subjects who inhaled concentrations of 340 mg/cu m (106 ppm) benzene in air for 5 hr excreted 29% as phenol, 3% as catechol and 1% as hydroquinone in the urine, mostly as ethereal sulfates. Most of the phenol and catechol was excreted within 24 hr, and the hydroquinone within 48 hr.
In men and women exposed to 52-62 ppm (166-198 mg/cu m) benzene for 4 hr, a mean of 46.9% was taken up, 30.2% was retained and the remaining 16.8% excreted as unchanged benzene in expired air.
In animals, expired air is the main route of elimination of unmetabolized benzene, while urine is the major route of excretion of benzene metabolites (with very little fecal excretion).
In a series of experiments conducted in a single-family residence from June 11 to 13, 1991, exposure to benzene through contaminated residential water was monitored. The residential water was contaminated with benzene and other hydrocarbons in 1986. Exposure was monitored for a person taking a 20-min shower and for people in other parts of the house during and after the shower. An average dermal dose of 168 ug was calculated for a 20-min shower using this water. The total benzene dose resulting from the shower was estimated to be approximately 281 ug (40% via inhalation, 60% via dermal), suggesting a higher potential exposure to benzene via dermal contact from the water than through vaporization and inhalation. This exposure was 2-3.5 times higher than the mean 6-hr inhalation dose received by the sampling team members in other parts of the house.
In Sprague-Dawley rats administered a single dose of 0.15, 1.5, 15, 150, or 500 mg/kg of 14C-benzene by gavage, benzene was rapidly absorbed and distributed to various organs and tissues within 1 hr of administration. One hour after rats were dosed with 0.15 or 1.5 mg/kg of benzene, tissue distribution of benzene was highest in liver and kidney, intermediate in blood, and lowest in the Zymbal gland, nasal cavity tissue, and mammary gland. At higher doses, beginning with 15 mg/kg, benzene disproportionately increased in the mammary glands and bone marrow. Bone marrow and adipose tissue proved to be depots of benzene at the higher dose levels. The highest tissue concentrations of benzene's metabolite hydroquinone 1 hr after administration of 15 mg/kg of benzene were in the liver, kidney, and blood, while the highest concentrations of the metabolite phenol were in the oral cavity, nasal cavity, and kidney. The major tissue sites of benzene's conjugated metabolites were blood, bone marrow, oral cavity, kidney, and liver for phenyl sulfate and hydroquinone glucuronide; muconic acid was also found in these sites. Additionally, the Zymbal gland and nasal cavity were depots for phenyl glucuronide, another conjugated metabolite of benzene. The Zymbal gland is a specialized sebaceous gland and a site for benzene-induced tumors. Therefore, it is reasonable to expect that lipophilic chemicals like benzene would partition readily into this gland. However, benzene did not accumulate in the Zymbal gland; within 24 hr after administration, radiolabel derived from 14C-benzene in the Zymbal gland constituted less than 0.0001% of the administered dose.
Monkeys were dosed intraperitoneally with 5-500 mg/kg radiolabeled benzene, and urinary metabolites were examined. The proportion of radioactivity excreted in the urine decreased with increasing dose, whereas the dose increased, more benzene was exhaled unchanged. This indicated saturation of benzene metabolism at higher doses. Phenyl sulfate was the major urinary metabolite. Hydroquinone conjugates and muconic acid in the urine decreased as the dose increased.

Environmental Fate and Exposure Potential

【Environmental Fate/Exposure Summary】
TERRESTRIAL FATE: Based on a classification scheme(1), a Koc value of 85(2), indicates that benzene is expected to have high mobility in soil(SRC). Volatilization of benzene from moist soil surfaces is expected to be an important fate process(SRC) given a Henry's Law constant of 5.56X10-3 atm-cu m/mole(3). The potential for volatilization of benzene from dry soil surfaces may exist(SRC) based upon a vapor pressure of 94.8 mm Hg(4). Benzene is expected to biodegrade in soils based on a biodegradation study in a base-rich para-brownish soil where 20 ppm benzene was 24% degraded in 1 week, 44% in 5 weeks, and 47% in 10 weeks(5). Anaerobic degradation of benzene in soil is not expected to be an important loss process based on various studies(6,7). In one study of chemical biotransformation under nitrate- and sulfate-reducing conditions, benzene was found to be stable for 60 days(6). In a related study, benzene did not undergo biodegradation in situ nor in laboratory controlled soil samples under denitrifying conditions(7).
AQUATIC FATE: Based on a classification scheme(1), a Koc value of 85(2), indicates that benzene is not expected to adsorb to sediment and suspended solids in water(SRC). Volatilization from water surfaces is expected(3) based upon a Henry's Law constant of 5.56X10-3 atm-cu m/mole(4). Using this Henry's Law constant and an estimation method(3), volatilization half-lives for a model river and model lake are 1 hr and 3.5 days, respectively(SRC). Anaerobic degradation of benzene in water is not expected to be an important loss process based on various studies(5). In one study of chemical biotransformation under nitrate- and sulfate-reducing conditions, benzene was found to be stable for 60 days(5). In aqueous solution, benzene will react with hydroxyl radical at a reaction rate of 7.8X10+9 L/mol sec; using the average OH radical concentration (1.0X10-17 molec/cu cm), benzene would have a half-life of 103 days(6). According to a classification scheme(7), a BCF ranging from 1.1-20(8) suggests the potential for bioconcentration in aquatic organisms is low.
AQUATIC FATE: Evaporation was the primary loss mechanism in winter in a mesocosm experiment which simulated a northern bay where the half-life was 13 days(1). In spring and summer the half-lives were 23 and 3.1 days, respectively(1). In these cases biodegradation plays a major role and takes about 2 days(1). However, acclimation is critical and this takes much longer in the colder water in spring(1). According to one experiment, benzene has a half-life of 17 days due to photodegradation(2) which could contribute to benzene's removal. In situations of cold water, poor nutrients, or other conditions less conducive to microbial growth, photolysis will play a important role in degradation(SRC). The half-life of benzene in sea water is about 5 hrs(3) based on its high Henry's Law constant of 5.56X10-3 atm-cu m/mole(4).
ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), benzene, which has a vapor pressure of 94.8 mm Hg at 25 deg C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase benzene is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be 13 days(SRC), calculated from its rate constant of 1.23X10-12 cu cm/molecule-sec at 25 deg C(3). The half-life in polluted atmospheres which contain nitrogen oxides or sulfur dioxide has been observed to shorten to 4-6 hrs(4). Vapor-phase benzene is also degraded in the atmosphere by atmospheric ozone radicals at an extremely slow rate; the half-life for this reaction in air is estimated to be 170,000 days(5). The reaction rate of benzene with nitrate radical in the atmosphere is estimated to be less than 0.3X10-16 cu cm/molecule sec at 25 deg C(3); the half-life for this reaction in air is estimated to be greater than or equal to 111 days based on an average concentration of nitrate radicals of 2.4X10+8 molec/cu cm(6). Benzene has a maximum absorbance frequency of 253 nm suggesting that direct photolysis will not be an important degradation process(7). Due to benzene's high water solubility, it may be removed from the atmosphere by rainfall(8).

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Phenoxyethane;Phenyl ethyl ether;Phenetole;Phenetole(8CI);Ethoxybenzene;Ethyl phenyl ether;NSC 406706;Phenetol;1-Phenyl ethyl alcohol;1-Phenyl ethyl a...

Benzene, dodecyl-

Dodecane,1-phenyl- (8CI);1-Dodecylbenzene;1-Phenyl-n-dodecane;1-Phenyldodecane;Alkylate P 1;Detergent Alkylate No. 2;Laurylbenzene;NSC102805;NSC 4584;...

Benzene, tridecyl-

Tridecane,1-phenyl- (6CI,7CI,8CI); 1-Phenyl-n-tridecane; 1-Phenyltridecane; DetergentAlkylate No. 5; Tridecylbenzene; Tridecylbenzol; n-Tridecylbenzen...

Benzene,(difluoromethoxy)-

(Difluoromethoxy)benzene;Anisole, α,α-difluoro- (6CI,7CI,8CI);Difluoromethyl phenyl ether;Phenyl difluoromethyl ether;α,α-Difluoroanisole;