Process for preparing para-phenylenediamine derivatives

摘要

An improvement in a process for the preparation of a p-aminodiarylamine by reduction of the corresponding nitroso or nitro compound with hydrogen in a hydrogenator in the presence of a catalyst is disclosed. The invention includes equipping the hydrogenator with filtration means capable of separating the p-aminodiarylamine product from the catalyst, whereby the p-aminodiarylamine product can be removed from the hydrogenator while the catalyst is retained therein, thereby permitting the reaction to be run semicontinuously or continuously.