- Process for the catalytic hydrogeneration of aromatic nitro compounds
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PCT No. PCT/EP96/01889 Sec. 371 Date Nov. 13, 1997 Sec. 102(e) Date Nov. 13, 1997 PCT Filed May 7, 1996 PCT Pub. No. WO96/36597 PCT Pub. Date Nov. 21, 1996One object of the invention is a process for the catalytic hydrogenation of aromatic nitro compounds in solution or in melt in the presence of hydrogen and at least one noble metal catalyst, nickel catalyst or cobalt catalyst, in which process a catalytic amount of at least one vanadium compound is present, wherein the vanadium has the oxidation state 0, II, IV or V. It has been found that in the catalytic hydrogenation of aromatic nitro compounds the accumulation of hydroxylamines can be almost completely prevented by the addition of catalytic amounts of vanadium compounds, which usually results in concentrations of 1% hydroxylamine. The resulting hydrogenated products are whiter (purer) than those obtained without the addition of the vanadium compound because almost no azo or azoxy compounds are obtained. The hydrogenation, in particular the final phase, proceeds faster than without said addition. Accordingly, substantial advantages with respect to quality constancy and economy are obtained.
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