Béchamp reduction

What is Béchamp reduction?

The reduction of aromatic nitro compounds to their corresponding aromatic amines can be achieved through the use of iron, ferrous salts, or an iron catalyst in aqueous acid. This reaction is commonly known as the Béchamp reduction, first reported by Béchamp in 1854.

Béchamp reduction
Béchamp reduction

Although zinc and tin can also be used in the presence of an acid, the reduction process may stop at intermediate stages, producing hydroxylamines, hydrazines, azoarenes, or azoxyarenes, indicating aspects of the reaction mechanism. The Béchamp reduction has a slow reaction rate and requires costly steam distillation, but it exhibits higher selectivity for the desired product than catalytic hydrogenation of aromatic nitro compounds. The addition of neutral organic solvents such as acetonitrile and propylene carbonate to the aqueous reaction mixture can improve the reaction yield. Recently, a highly chemoselective catalytic hydrogenation of nitrobenzenes using homogeneous iron complex catalysts has been developed.

References

Béchamp, A. J. “De l’action des protosels de fer sur la nitronaphtaline et la nitrobenzine.” [On the action of iron protosalts on nitronaphthaline and nitrobenzine.Nouvelle méthode de formation des bases organiques artificielles de Zinin Ann Chim Phys 42 (1854): 186-96.

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