| Bechamp reduction | |
|---|---|
| Named after | Antoine Béchamp |
| Reaction type | Organic redox reaction |
| Identifiers | |
| RSC ontology ID | RXNO:0000498 |
TheBéchamp reduction (orBéchamp process) is achemical reaction that convertsaromaticnitro compounds to their correspondinganilines usingiron as the reductant:[1]
This reaction was once a major route to aniline, buthydrogenation ofnitrobenzene usingpalladium on charcoal is the preferred method.[2]
The reaction was first used byAntoine Béchamp to reduce2-nitronaphthalene andnitrobenzene to2-naphthylamine andaniline, respectively.[3] The Béchamp reduction is broadly applicable to aromatic nitro compounds.[4][5]Aliphatic nitro compounds are however more difficult to reduce, often remaining as ahydroxylamine. Tertiary aliphatic nitro compounds, however, are converted in good yield to amines using the Béchamp reduction.[6]
The reduction proceeds in a multistep manner. First, the nitro group is reduced tonitroso, which undergoes hydrogenation to ahydroxylamino group prior to further reduction to the amine.[7]
The traditional Béchamp reduction cogenerates gray-black iron oxides. TheLaux process is based on the finding that the oxide coproduct is strongly affected by various additives, such asferrous chloride,aluminium chloride, and even simplysulfuric acid, which are added before heating the iron-nitrobenzene mixture. The innovations from Laux have shifted the emphasis of the Béchamp reduction for the manufacture of anilines to the production of valuableiron oxide pigments.[8] The method is still effective for reduction of nitroaromatics.[9]