ABSTRACT

Aniline was identified as a constituent of coal tar over a hundred years ago. There are two routes to aniline in commercial production. These are: catalytic hydrogenation of nitrobenzene; and ammonolysis of phenol. Most world production of aniline is based on nitrobenzene, but two producers, Mitsui Petrochemical and USS Chemicals, utilize the phenol process. The organic layer has any remaining water removed in a drying tower before high-purity aniline is recovered by distillation. The aniline mixture is purified using vacuum distillation to remove high boiling compounds. Over 50% of aniline is consumed in the manufacture of diphenylmethane diisocyanate, formed by condensation with formaldehyde, which is used to produce rigid polyurethane foam. Aniline is toxic, readily absorbed by the skin and a suspected carcinogen. When handling aniline good ventilation is essential. Although it is a combustible liquid, aniline can normally be handled with little risk of fire.