A six-carbon aromatic annulene in which each carbon atom donates one of its two 2p electrons into a delocalised pi system. A toxic, flammable liquid byproduct of coal distillation, it is used as an industrial solvent. Benzene is a carcinogen that also damages bone marrow and the central nervous system.
Benzene is also converted to cyclohexane, which is used to produce nylon and synthetic fibers.
Benzene occurs in coal and coal-tar distillationproducts and in petroleum products suchas gasoline. It is also found in the gases andleachates of landfills for industrial wastes,construction debris, and landscaping refuse(Oak Ridge National Laboratory 1989). Traceamounts of benzene, toluene, xylenes, andother volatile organics have been found inthe soils and groundwaters near many sanitarylandfills (U.S. EPA 1989a,b). Kramer(1989) has assessed the level of exposuresto benzene during removal, cleaning, pumping,and testing of underground gasoline storagetanks. The average human exposureswere 0.43–3.84 ppm (in 1.5–6 hours) and thehighest short-term (15–minute) exposure was9.14 ppm. Benzene also occurs in the tobaccosmoke (Hoffmann et al. 1989); thus the riskof its exposure may enhance from inhalingsuch smoke.
Benzene is used as a solvent for waxes,resins, and oils; as a paint remover; as a diluentfor lacquers; in the manufacture of dyes,pharmaceuticals, varnishes, and linoleum;and as a raw material to produce a numberof organic compounds.
Melting point | 5.5 °C (lit.) |
Boiling point | 80 °C (lit.) |
density | 0.874 g/mL at 25 °C (lit.) |
vapor density | 2.77 (vs air) |
vapor pressure | 166 mm Hg ( 37.7 °C) |
refractive index | n20/D 1.501(lit.) |
Fp | 12 °F |
storage temp. | room temp |
solubility | Miscible with alcohol, chloroform, dichloromethane, diethyl ether, acetone and acetic acid. |
pka | 43(at 25℃) |
form | Liquid |
color | APHA: ≤10 |