Patent ID: 7312362

Claim:
A process for the production of di- and polyamines of the diphenylmethane series comprising: 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 containing di- and polyamines into an organic phase containing di- and polyamines and an aqueous phase; d) separating by distillation the water and aniline from the organic phase containing di- and polyamines; wherein d1) the distillation in step d) comprises at least one pre-evaporation stage and at least one distillation stage, d2) aniline and water are partially separated off in the pre-evaporation stage from the organic phase containing di- and polyamines by flash evaporation, and d3) in the subsequent distillation stage, the remaining aniline and water are separated off, such that di- and polyamines containing less than about 1,000 ppm of water and less than about 200 ppm of aniline, based on the weight of the di- and polyamines, are obtained and e) cooling the di- and polyamines containing less than about 1,000 ppm of water and less than about 200 ppm of aniline.