Process for preparing alkylated p-phenylenediamines

摘要

A process for preparing alkylated p-phenylenediamine having the steps of reacting aniline and nitrobenzene in presence of a complex base catalyst to obtain 4-aminodiphenylamine intermediates, hydrogenating the 4-aminodiphenylamine intermediates to 4-aminodiphenylamine in presence of a hydrogenation catalyst, and reductively alkylating the 4-aminodiphenylamine to alkylated p-phenylenediamine.

主权项

1. A process for preparing alkylated p-phenylenediamine, comprising
reacting aniline and nitrobenzene in a condensation reaction in presence of a complex base catalyst to obtain 4-aminodiphenylamine intermediates, hydrogenating the 4-aminodiphenylamine intermediates to 4-aminodiphenylamine in presence of a hydrogenation catalyst, and reductively alkylating the 4-aminodiphenylamine to alkylated p-phenylenediamine, wherein the aniline is in excess to the nitrobenzene in the condensation reaction; the complex base catalyst comprises a tetraalkyl ammonium hydroxide and a salt thereof, and an alkali metal hydroxide or oxide; molar ratio of total molar amount of the tetraalkyl ammonium hydroxide and the salt thereof to molar amount of the alkali metal hydroxide or oxide in the complex base catalyst is in a range of 2.5 to 5:1, and the salt of the tetraalkyl ammonium hydroxide is represented by
[(R1)(R2)(R3)(R4)N]+nXn− wherein R1, R2, R3, and R4, identical or different, respectively, is an alkyl having from 1 to 4 carbon atoms and said alkyl being optionally substituted by a hydrophilic substitute; and Xn− is selected from the group consisting of carbonate radical, bicarbonate radical, C1-C2-alkyl carbonate radical, and C1-C2-alkyl sulfate radical; n is 1 or 2.