Simplified low-energy separation of high-purity 6-aminocapronitrile from its mixtures with adiponitrile and hexamethylenediamine by a three-step distillative method

摘要

6-Aminocapronitrile (6-ACN) is separated from its mixtures with adiponitrile and hexamethylenediamine (HMDA) by a 3-step distillative process. Distillative separation of 6-aminocapronitrile (6-ACN) from its mixtures with adiponitrile and hexamethylenediamine (HMDA) comprises: (a) separating out HMDA to give a mixture (M-I) of HMDA content below 1 wt.%; (b) partly or completely separating out 6-ACN from (M-I) to give a mixture (M-II) containing less than 1 wt.% of materials which are higher boiling than 6-ACN under distillation conditions and which cannot be formed by heat dimerization of 6-ACN; and (c) partly or completely separating out any existing HMDA from (M-II) to give a mixture (M-III) with a HMDA content higher than (M-II) and a mixture (M-IV) with a HMDA content lower than (M-II).