1066. Benzene

Nomenclature

CAS number: 71-43-2
Benzol; cyclohexatriene.
C6H6; mol wt 78.11.
C 92.26%, H 7.74%.

Description and references

Natural component of petroleum, usually <1.0% by weight. Discovered by Faraday in compressed oil gas in 1825. Obtained in the coking of coal and in the production of illuminating gas from coal. Manuf by catalytic reforming and separation of aromatic compounds, thermal or catalytic dealkylation of toluene, toluene disproportionation; from pyrolysis gasoline. Purification by washing with water: GB 863711 (1961 to Schloven-Chemie and H. Koppers GmbH), C.A. 55, 16971f (1961). Lab prepn from aniline: Gattermann-Wieland, Praxis des Organischen Chemikers (de Gruyter, Berlin, 40th ed., 1961) p 247. Production of pure benzene: French, Ind. Chem. 39, 9-12 (1963). Manuf: Faith, Keyes & Clark's Industrial Chemicals, F. A. Lowenheim, M. K. Moran, Eds. (Wiley-Interscience, New York, 4th ed., 1975) pp 126-137. Physical properties: Thorne et al., Ind. Eng. Chem. Anal. Ed. 17, 481 (1945). Solubility studies: F. P. Schwarz, Anal. Chem. 52, 10 (1980). Toxicity data: Kimura et al., Toxicol. Appl. Pharmacol. 19, 699 (1971). Review: W. Fruscella in Kirk-Othmer Encyclopedia of Chemical Technology vol. 4 (Wiley-Interscience, New York, 4th ed., 1992) pp 73-103. Reviews of toxicology: R. Snyder et al., Rev. Biochem. Toxicol. 3, 123-154 (1981); D. J. Paustenbach et al., Environ. Health Perspect. 101, Suppl. 6, 177-200 (1993); and human exposure: Toxicological Profile for Benzene (PB98-101157, 1997) 463 pp. Symposia on metabolism, toxicity and carcinogenesis: Environ. Health Perspect. 82, 3-310 (1989); ibid. 104, Suppl. 6, 1121-1441 (1996).

Chemical structure

Properties

Clear, colorless, volatile liquid; characteristic odor. d415 0.8787. bp 80.1°. mp 5.5°. nD20 1.50108. Flash pt, closed cup: 12°F (11°C). Soly in water at 23.5°C (w/w): 0.188%. Flammable. Miscible with alcohol, chloroform, ether, carbon disulfide, carbon tetrachloride, glacial acetic acid, acetone, oils. Keep in well-closed containers in a cool place and away from fire. LD50 orally in young adult rats: 3.8 ml/kg (Kimura).

Derivative

Sodium salt.

Nomenclature

CAS number: 1623-99-0
Phenyl sodium.
C6H5Na; mol wt 100.09.
C 72.00%, H 5.04%, Na 22.97%.

Description and references

Prepn: Schlosser, Angew. Chem. 76, 267 (1964).

Properties

Solid mass, dec by water, acids, alkalies. Sol in liquid ammonia, tetrahydrofuran.

Caution

Potential symptoms of overexposure by inhalation or ingestion are dizziness, headache, vomiting, visual disturbances, staggering gait, hilarity, fatigue, anorexia, lassitude, CNS depression, loss of consciousness, respiratory arrest. Chronic exposure has been associated with bone marrow depression and leukemia. Direct contact may cause irritation of eyes, nose, respiratory system and skin; dermititis may develop due to defatting action. Aspiration into the lung may lead to chemical pneumonitis. See Patty's Industrial Hygiene and Toxicology vol. 2B, G. D. Clayton, F. E. Clayton, Eds. (Wiley-Interscience, New York, 4th ed., 1994) pp 1306-1326; NIOSH Pocket Guide to Chemical Hazards (DHHS/NIOSH 97-140, 1997) p 26. Benzene is listed as a known human carcinogen: Report on Carcinogens, Eleventh Edition (PB2005-104914, 2004) p III-26.

Use

Manuf of industrial chemicals such as polymers, detergents, pesticides pharmaceuticals, dyes, plastics, resins. Organic solvent for waxes, resins, oils, natural rubber, etc. Reference for quantitating compds. Gasoline additive.

Therapeutic Category (Veterinary)

Has been used as a disinfectant.