Process for production of di- and polyamines of the diphenylmethane series

Abstract

Process for the production of di- and poly(diamino diphenyl methane) comprising the steps of (a) reacting aniline and formaldehyde in the presence of an acid catalyst to produce a reaction mixture containing di- and polyamines; (b) neutralizing the reaction mixture containing di- and polyamines; (c) separating the neutralized reaction mixture into an organic phase containing di- and polyamines and an aqueous phase; (d) further treating the organic phase separated off in step (c) by (d1) washing with water followed by (d2) separating the washed mixture into an organic phase and an aqueous phase and (d3) further fractionation of the organic phase to produce purified di- and polyamines on the one hand and aniline/water on the other hand; (e) further treating the aqueous phase separated off in step (c) by (e1) washing with aniline followed by (e2) separating the washed mixture into an aqueous phase and an organic phase and (e3) further treatment of the aqueous phase to remove the aniline thereby leaving an effluent stream; wherein phase separation in step (c) and/or step (d2) is facilitated by using any of the following methods either on its own or in combination with one or more of the other methods: (A) removal of some of the aromatic amine from the neutralized reaction mixture obtained in step (b) or the organic phase separated in step (c); (B) addition of di- and polyamine to the organic phase separated in step (c); (C) return of some of the organic phase obtained in step (d2) or (d3) to the washed mixture in step (d1).

Dependencies are inferred from the claim text.