Recovery of isophoronediamine, useful in production of e.g. polyurethanes, comprises distillation of the crude diamine into a fraction having a cis/trans ratio of greater than 73/27 and a fraction having a cis/trans ratio of less than 66/34

摘要

Recovery of isophoronediamine (IPDA) comprises preparation of IPDA having a cis/trans isomer ratio of less than 73/27 and separation into at least 5 fractions by distillation including an IPDA fraction having a cis/trans ratio of greater than 73/27 and a fraction having a cis/trans ratio of less than 66/34. A process for the recovery of 3-aminomethyl-3,5,5-trimethylcyclohexylamine (isophoronediamine, IPDA) comprises; (a) preparation of IPDA having a cis/trans isomer ratio of less than 73/27; (b) introduction of IPDA to the middle region of a distillation column having inserts and distillation of IPDA at 5-300 degreesC and 10-2000 mbar; (c) optionally further purification of the IPDA from (b) by distillation in at least one further column whereby the IPDA from step (b) and (c) are separated into at least 5 fractions comprising an organic fraction (1a) containing impurities having a lower b. pt. than trans-IPDA, an aqueous fraction (1b) containing impurities having a lower b. pt. than trans-IPDA, a fraction (2) containing impurities having a higher b. pt. than cis-IPDA, an IPDA fraction (3) having a cis/trans ratio of greater than 73/27 and an IPDA fraction (4) having a cis/trans ratio of less than 66/34.