Reduction of nitro compounds with aqueous solutions of a formate

In a process for the reduction of aromatic nitro compounds selected from the class consisting of nitronaphthalene monosulphonic acids, nitronaphthalene disulphonic acids, nitronaphthalene trisulphonic acids, nitrobenzene sulphonic acids, dinitrobenzene sulphonic acids, dinitromesitylene sulphonic acid, substituted nitrobenzene sulphonic acids in which the substituents are selected from acetylamino, methyl, methoxy, hydroxy, aminoanilino, methoxyanilino, cyclohexylamino and .beta.-(nitro-sulphophenyl)-ethenyl, and substituted nitrobenzene carboxylic acids in which the substituents are selected from acetylamino, hydroxy and sulphonic acid, the improvement which consists of treatment of said compounds with an aqueous solution of a formate in the presence of a hydrogenation catalyst based on platinum, palladium or ruthenium at a temperature up to the boiling point and at a pH of 2 to 12.