PROCESS FOR MAKING POLYAMINOPOLYPHENYL METHANES USING A MIXED SOLID ACID CATALYST SYSTEM

A method for preparing aromatic polyamines comprising (1) preparing a non-aqueous aminal solution; (2) contacting the non-aqueous aminal solution and an acidic siliceous catalyst to form a benzylamine intermediate; (3) contacting the benzylamine intermediate and an ion exchange resin catalyst based on a styrene-divinylbenzene copolymer to form an aromatic polyamine reaction mixture containing a polyaminopolyphenyl methane product; and (4) recovering the polyaminopolyphenyl methane product from the aromatic polyamine reaction mixture. The method, which may be practiced continuously, offers high 4,4′-methylene dianiline yield, reduced impurities, extended catalyst life, and, therefore, improved economics, when compared with many conventional methods to prepare polyaminopolyphenyl methanes.