Process for the production of polyamine mixtures of the polyamino-polyaryl-polymethylene series

In a process for production of polyamines of the diphenylmethane series through a condensation reaction of aniline with formaldehyde in the presence of an acid catalyst, neutralization of the acid catalyst after reaction completion, and distillation of the resultant polyamine mixture, the improvement wherein:

• a) aniline is reacted with formaldehyde in the mole ratio of 1.5:1 to 10:1 at temperatures between 10.degree. and 150.degree. C.,
• b) an acid catalyst is thereafter added to the reaction mixture at a mole ratio of aniline to acid catalyst of from 2:1 to 100:1 (corresponding to a protonation degree of 1 to 50%) and the temperature is from 10.degree. to 150.degree. C., and wherein the water formed during the condensation reaction is removed either before step b) or after step b),
• c) the temperature of the mixture obtained from b) is increased by at least 40.degree. C. in no more 15 minutes, and thereafter, if necessary, heating of the mixture is continued to a final temperature between 105.degree. and 200.degree. C., with the proviso that the reaction time is from 10 to 300 minutes after the temperature increase, and
• d) the reaction mixture from c) is distilled after neutralization of the acid catalyst.