PROCESS FOR THE PREPARATION OF P-AMINO-BENZOIC ACID

摘要

A two-stage process for producing para-aminobenzoic acid by first reacting certain lower alkyl or glycol monoesters of terephthalic acid or specific salts thereof or mixtures thereof with ammonia in liquid phase at elevated temperatures and pressures to obtain a terephthalic acid monoamide intermediate, removing substantially all ammonia from this intermediate and then converting it into the para-aminobenzoic acid product by the Hofmann reaction, preferably using a sodium hypochlorite solution. The para-aminobenzoic acid, either as the free acid or in the form of its salts or esters is a known product having many uses.