| abstract |
The invention relates to a method for producing diphenylmethandiamine, comprising the steps of a) reacting aniline with formaldehyde in the presence of an acid, b) neutralizing most of the acid with ammonia and/or aqueous ammonia solution, c) separating the reaction mixture from step b) into an aqueous and an organic phase, d) neutralizing the remaining part of the acid in the organic phase with aqueous alkali hydroxide solution, e) separating the reaction mixture from step d) into an aqueous and an organic phase, f) treating the aqueous phase obtained in step c) or optionally the unified aqueous phases from steps c) and e) with at least one oxide or hydroxide of an alkaline earth metal, and g) separating the ammonia obtained in step f). |