Patent ID: 7943724

Claim:
A process for preparing diamino diphenyl methane and poly(diamino diphenyl methane) comprising: (i) preparing an aniline/water mixture having a water content ranging from 0.1 to 7 wt%; (ii) introducing hydrogen chloride gas to the mixture of step (i) such that the hydrogen chloride gas is absorbed into the aniline; (iii) introducing, optionally with simultaneous mixing, formaldehyde into the mixture of step (ii) in one or more stages, optionally with cooling, to yield an intermediate mixture; (iv) heating said intermediate mixture to produce the desired mixture of primary amine isomers and homologues; (v) neutralizing the acid typically a sodium hydroxide solution, separation and washing of the organic and brine phases, followed by removal and recycling of excess unreacted aniline.