Patent ID: 8759585

Claim:
A process for preparing diphenylmethanediamine and more highly condensed polyphenylenepolymethylenepolyamines, comprising: a) reacting aniline with formaldehyde in the presence of an acid, b) neutralizing a first part of the acid with ammonia or an aqueous ammonia solution, to obtain a first reaction mixture, c) separating the first reaction mixture into a first aqueous phase and a first organic phase, d) neutralizing a second part of the acid, present in the first organic phase, with an aqueous alkali metal hydroxide solution, to obtain a second reaction mixture, e) separating the second reaction mixture into a second aqueous phase and a second organic phase, f) treating the first aqueous phase or optionally a combination of the first and second aqueous phases with at least one oxide or hydroxide of an alkaline earth metal, to obtain a third reaction mixture, comprising ammonia, and g) removing the ammonia from the third reaction mixture.