Aniline is a toxic organic compound with the formula C6H5NH2. Consisting of a phenyl group attached to an amino group, aniline is the prototypical aromatic amine. Its main use is in the manufacture of precursors to polyurethane and other industrial chemicals. Like most volatile amines, it possesses the odor of rotten fish. It ignites readily, burning with a smoky flame characteristic of aromatic compounds.[4]

Production[edit]

Industrial aniline production involves two steps. First, benzene is nitrated with

a concentrated mixture of nitric acid andsulfuric acid at 50 to 60 °C to

yield nitrobenzene. The nitrobenzene is then hydrogenated (typically at 200–

300 °C) in the presence of metal catalysts.

The reduction of nitrobenzene to aniline was first performed by Nikolay

Zinin in 1842 using inorganic sulfide as a reductant (Zinin reaction ).

Aniline can alternatively be prepared from ammonia and phenol derived from

the cumene process .[4]

In commerce, three brands of aniline are distinguished: aniline oil for blue,

which is pure aniline; aniline oil for red, a mixture of equimolecular quantities

of aniline and ortho- and para-toluidines; and aniline oil for safranine, which

contains aniline and ortho-toluidine, and is obtained from

the distillate (échappés) of the fuchsine fusion.[citation needed]

Related aniline derivatives[edit]

Many analogues of aniline are known where the phenyl group is further

substituted. These include toluidines, xylidines,chloroanilines, aminobenzoic

acids, nitroanilines, and many others. They often are prepared by nitration of

the substituted aromatic compounds followed by reduction. For example, this

approach is used to convert toluene into toluidines and chlorobenzene into 4-

chloroaniline.[4]

Reactions[edit]

The chemistry of aniline is rich because the compound has been cheaply

available for many years. Below are some classes of its reactions.

Oxidation[edit]

The oxidation of aniline has been heavily investigated, and can result in

reactions localized at nitrogen or more commonly results in the formation of

new C-N bonds. In alkaline solution, azobenzene results, whereas arsenic

acidproduces the violet-coloring matter violaniline. Chromic acid converts it

into quinone, whereas chlorates, in the presence of certain metallic salts

(especially of vanadium), give aniline black. Hydrochloric acid and potassium

chlorate give chloranil. Potassium permanganate in neutral solution oxidizes it

to nitrobenzene, in alkaline solution toazobenzene, ammonia and oxalic acid,

in acid solution to aniline black. Hypochlorous acid gives 4-aminophenol and

para-amino diphenylamine. Oxidation with persulfate affords a variety

of polyanilines compounds. These polymers exhibit rich redox and acid-base

properties.