Method of influencing the cis/trans isomer ratio of isophoronediamine in its preparation from isophoronenitrile

摘要

A method of controlling the cis/trans isomer ratio in the preparation of isophoronediamine by the aminating hydrogenation of isophoronenitrile in the presence of ammonia, H2 and a catalyst. The reaction takes place in two temperature steps, initially at 10 DEG to 90 DEG C. and then at above 90 DEG to 150 DEG C. with a temperature difference of at least 30 DEG C. between the two steps, the contact time being shorter in the first step than in the second. The cis/trans ratio is increased by lowering the temperature of the first step.