Patent ID: 8822726

Claim:
A process for preparing at least one bis(aminophenyl)alkane in a catalytic reaction, comprising reacting an aromatic amine, which may be substituted or unsubstituted, with a C 1 -C 3 aldehyde in the presence of a heterogeneous catalyst, wherein: the catalyst is a mesoporous acidic ion exchanger based on a divinylbenzene/styrene copolymer; the catalyst has acidic centers, measured in accordance with DIN 54 403, in a concentration of 2 to 6 eq/kg; an average pore diameter of catalyst particles, measured in accordance with ASTM D 4222, is 10 to 32 nm, and a polynuclear compound content of a reaction mixture formed is >10% and ≦15% by weight and N methyl compounds content is ≦1% by weight.