Method for producing diamines and polyamines of the diphenylmethane series

摘要

The invention relates to a method for producing diamines and polyamines of the diphenylmethane series, wherein first aniline and formaldehyde are reacted in the absence of an acidic catalyst to form a reaction mixture containing animal and water and, after the water has been separated the aminal is reacted by acid catalysis to form a reaction mixture containing diamines and polyamines of the diphenylmethane series, wherein the separation of the water from the aminal is supported by the use of a coalescence aid. According to the invention, a filter bed made front coalescence fiber material is used an coalescence aid.

主权项

1. A process for the preparation of di- and polyamines of the diphenylmethane series, comprising:
a) converting aniline and formaldehyde in the absence of an acidic catalyst to a reaction mixture comprising aminal and water, b) removing water at least in part from the reaction mixture obtained in step a), giving an organic phase (1) comprising the aminal, c) converting the organic aminal-comprising phase (1) obtained in step b) in the presence of an acidic catalyst, giving a reaction mixture comprising di- and polyamines of the diphenylmethane series, and d) neutralizing the reaction mixture comprising di- and polyamines of the diphenylmethane series obtained in step c) and then subjecting the neutralized reaction mixture to a work-up involving washing and distillation,wherein the separation of the water from the reaction mixture obtained in step a) comprises
b.1) separating the reaction mixture obtained in step a) in a separating container into an aqueous and an organic phase (1a), and then b.2) passing the aqueous phase obtained in step b.1)
through a filter bed of coalescence fiber material andthen separating the aqueous phase obtained thereby into an aqueous phase and an organic phase (1b), and then b.3) combining the organic phase (1b) obtained in step b.2) with the organic phase (1a) obtained in step b.1) to give the organic phase (1).