Patent ID: 6139693
Filing Date: 2000-10-31
Classification: C07C,Y10S

Abstract:
A process for recovering hexamethylenediamine (I) from a mixture (II) comprising(I) hexamethylenediamine,(III) hexamethyleneimine,(IV) a compound selected from the group consisting of 2-aminomethylcyclopentylamine and 1,2-diaminocyclohexane,(V) an imine,(VI) adiponitrile and 6-aminocapronitrile,which comprises:(a) distilling a mixture (II) in a column at a pressure drop from the bottom to the top of from 1 to 500 mbar, a pressure in the bottom within the range from 1 to 500 mbar, a pressure at the top within the range from 1 to 500 mbar and a bottom temperature of from 100 to 300.degree. C. to obtain(a1) a low boiling fraction comprising essentially (III) as overhead product,(a2) a medium boiling fraction (VII) comprising (I), (IV) and (V) as sidestream takeoff, and(a3) a high boiling fraction comprising (V) and (VI) as bottom product,(b) distilling the mixture (VII) to obtain(b1) an overhead product comprising essentially (IV), and(b2) a mixture (VIII) comprising (I) and (V) as bottom product, and(c) distilling the mixture (VIII) to obtain(c1) (I) as overhead product, and(c2) a bottom product comprising (V).