Bechamp reduction


The Bechamp reduction is used to reduce aromatic nitro compounds to their corresponding anilines, using iron and hydrochloric acid.
This reaction was originally used to produce large amounts of aniline for industry, but catalytic hydrogenation is the preferred method. The Bechamp reaction is of interest as a route to iron oxide pigments.

Reaction history and scope

The reaction was first used by Antoine Béchamp to reduce nitronaphthalene and nitrobenzene to naphthylamine and aniline, respectively. The Bechamp reduction is broadly applicable to aromatic nitro compounds.
Aliphatic nitro compounds are however more difficult to reduce, often remaining as the hydroxylamine. Tertiary aliphatic nitro compounds, however, are converted in good yield to the amine compound using the Bechamp reduction.

Proposed mechanism

The reduction is thought to proceed in a multistep manner. First, the nitro group is reduced to a nitroso group, followed by a hydration reaction to a hydroxylamino group. Another reduction step then yields the amine.