Basf Se Corporation

Klaus-Peter Metzner

Torsten Mattke

Kai Thiele

Kerstin Heinen

Viktor Ladnak

Silvia Tauro

A process for preparing an aromatic polyamine mixture including 4,4'-methylenedi(phenylamine) and higher homologues of MDA is provided. The process includes steps of (i) reaction of aniline with formaldehyde by means of an acid catalyst to form a crude product mixture (I), (ii) neutralization of the crude product mixture (I) and removal of the salts formed; (iii) isolation of aniline; (iv) distillation of the resulting crude product mixture so as to separate off (iv-1) a mixture (II) of MDA isomers (II-1) containing from 8 to 20% by weight of 4,4&#x2032;-methylenedi(phenylamine) and not more than 0.3% by weight of secondary components (II-2) and (iv-2) a low boiler mixture of at least 55% by weight of secondary components (II-2) and MDA isomers (II-1); and (v) recirculation of the mixture (II).

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Auburn Hills, MI, United States of America

Klaus-Peter Metzner