METHOD FOR OBTAINING HEXAMETHYLENE DIAMINE FROM MIXTURES CONTAINING HEXAMETHYLENE DIAMINE

摘要

The invention relates to a method for obtaining hexamethylene diamine (I) from a mixture (II) containing (I) hexamethylene diamine, (III) hexamethylenimine, (IV) a compound selected from the group consisting of 2-aminomethyl cyclopentylamine and 1,2-diaminocyclohexane, (V) an imine, and (VI) adipodinitrile and 6-aminocaproic acid nitrile. According to said method, (a) a mixture (II) is subjected to distillation, yielding (a1) a low-boiling fraction which essentially contains (III), (a2) a medium-boiling fraction (VII) containing (I), (IV) and (V), and (a3) a high-boiling fraction containing (V) and (VI); (b) a mixture (VII) is subjected to distillation, yielding (b1) an overhead which essentially contains (IV) and (b2) a mixture (VIII) containing (I) and (V) as bottom residue; and (c) a mixture (VIII) is subjected to distillation, yielding (c1) (I) as overhead and (c2) a bottom residue which contains the essential part of (V).