4-AMINODIPHENYLAMINE PRODUCTION PROCESS Russian patent published in 2004 - IPC

FIELD: industrial organic synthesis. SUBSTANCE: 4- aminodiphenylamine is obtained through intermediate 4-nitrodiphenylamine and/or 4-nitrosodiphenylamine, and/or their salts prepared by reaction of aniline with nitrobenzene in liquid medium at 50 to 130 C at atmospheric or reduced pressure of inert gas or in presence of air oxygen. 4-Nitrodiphenylamine or 4-nitrosodiphenylamine in presence of byproducts is then subjected to catalytic hydrogenation to give 4- aminodiphenylamine mixed with by- products. Unconverted starting compounds are recycled. Reaction of aniline with nitrobenzene is effected in reaction system including solution of salts of zwitter-ions with hydroxides having general formula HO^-[(R¹R²R³)N⁺-CHR⁴-(CH₂)_X-Y^-]Z⁺, where R¹ and R² represents radical from methyl to dodecyl; R³ represents methyl or ethyl; R⁴ hydrogen or methyl; n is integer from 0 to 5; Y^- represents CO-2

, SO-3, and Z⁺ alkali metal (Na, K, Cs) or tetrasubstituted quaternary ammonium (such as tetramethylammonium) cation, or their mixtures, provided that amount of both zwitter-ion salts and hydroxides is equal to at least equimolar amount regarding nitrobenzene amount and aniline-to-nitrobenzene molar ratio ranges from 6.4:1 to 9.4:1. Recycling involves at least half reaction mass. EFFECT: increased catalyst activity and optimized process parameters. 5 cl, 10 tbl, 21 ex