C6H5NO2, the simplest aromatic nitro compound; an oily light yellow liquid. Melting point, 5.7°C; boiling point, 210.9°C; density, 1.987 g/cm3 at 25°C. It is poorly soluble in water but mixes well with organic solvents.
Upon reduction, nitrobenzene is converted to aniline or hydrazobenzene, depending on the conditions. Under the action of acids, hydrazobenzene isomerizes to benzidine. Nitration, sulfonation, and chlorination of nitrobenzene take place mainly at the meta- position to the nitro group, for example:
Nitrobenzene is produced by nitration of benzene by a nitrating mixture. It is poisonous, with a maximum permissible concentration in air of 3 mg/m3 in work areas and 0.008 mg/m3 in residential buildings.
Nitrobenzene is mainly used in the production of aniline. In small quantities, nitrobenzene is also used in the production of intermediates for dyes (methanilic acid and benzidine), and also certain dyes (for example, induline).