Phenylamine

Phenylamine (C₆H₅NH₂), colourless liquid, slightly soluble in water and soluble in organic solvents. Formerly known as aniline, it was first prepared in 1826 as one of the products obtained by heating indigo to a high temperature. The word aniline is derived from the specific name, anil, of the indigo plant, which in turn is derived from the Sanskrit word nila (indigo).

In 1856 the British chemist Sir William Henry Perkin, while attempting to synthesize quinine, treated impure phenylamine with potassium dichromate and obtained a violet substance that could be used as a dye. Perkin named this material mauve and set up a factory to manufacture it. The enterprise was highly successful, and in a short time other synthetic dyestuffs, prepared from phenylamine or from other derivatives of coal tar, were competing with natural dyes.

Phenylamine is most readily prepared for commercial use by the reduction of nitrobenzene by iron and hydrochloric acid. It is also prepared commercially by the action of ammonia under high pressure on chlorobenzene in the presence of a catalyst. The raw material in both cases is made from benzene.

Currently, the principal use of phenylamine is in making an important class of plastics called polyurethanes. It also has important uses in making dyes, drugs (for example, sulphanilamide), explosives, and many other synthetic chemicals.

Phenylamine melts at -6.2° C (20.8° F) and boils at 184.3° C (363.8° F).