PROCESS FOR THE PRODUCTION OF DI-AND POLYAMINES OF THE DIPHENYLMETHANE SERIES

摘要

Preparation of di- and polyamine of the diphenylmethane series comprises transferring aniline and formaldehyde to a reaction mixture containing di- and polyamine, in the presence of an acid catalyst, neutralizing the reaction mixture containing di- and polyamine, introducing the neutralized reaction mixture containing di- and polyamine into an organic phase containing di- and polyamine and an aqueous phase, distillatively separating water and aniline form the organic phase, and cooling the obtained di- and polyamine. Preparation of di- and polyamine of the diphenylmethane series comprises: (a) transferring aniline and formaldehyde to a reaction mixture containing di- and polyamine, in the presence of an acid catalyst, (b) neutralizing the reaction mixture containing di- and polyamine, (c) introducing the neutralized reaction mixture containing di- and polyamine into an organic phase containing di- and polyamine and an aqueous phase, (d) distillatively separating water and aniline form the organic phase, where the distillation in step (d) comprises at least a pre-evaporation step and at least a distillation step; in the pre-evaporation step aniline and water are partially separated from the organic phase containing di- and polyamine by open evaporation; the further aniline and water are removed in the subsequent distillation step and the obtained di- and polyamine contains less than 1000 ppm of water and less than 200 ppm of aniline, based on the weight of di- and polyamine, and (e) cooling the obtained di- and polyamine. An independent claim is included for the preparation of di- and polyisocyanate of the diphenylmethane series comprising preparing di- and polyamine and subsequently reacting the amine with a phosgene.