Patent ID: 7084302

Claim:
A process for preparing 4-aminodiphenylamine comprising reacting nitrobenzene and aniline in presence of a complex base catalyst for condensation reaction to form a reaction mixture comprising 4-nitrodiphenylamine and 4-nitrosodiphenylamine; hydrogenating the reaction mixture in presence of hydrogen, a powdery composite catalyst, and a hydrogenation solvent to obtain a hydrogenation reaction product; separating, recovering, and reusing the complex base catalyst and the powdery composite catalyst from the hydrogenation reaction product; separating, recovering, and reusing aniline, and optionally water, from the hydrogenation reaction product; refining the hydrogenation reaction product to obtain 4-aminodiphenylamine, wherein the complex base catalyst comprises tetraalkyl ammonium hydroxide, alkali metal hydroxide or oxide, and tetraalkyl ammonium salt, the powdery composite catalyst comprises nickel, aluminum, and a component A that is at least one selected from the group consisting of Fe, Cu, Co, Mn, Cr, Mo, B and P.