PROCESS FOR CONTINUOUS PURIFICATION OF CRUDE CAPROLACTAM PREPARED FROM 6-AMINOCAPRONITRILE

Cleaning raw caprolactam by hydration, subsequent treatment in an acid mediu m and final distillation in an alkaline medium, in which (a) 6-amino capronitrile is converted into raw caprolactam by reaction with water, (b) difficultly and easily boiling components are removed from the raw caprolactam from step (a); (c) the raw caprolactam from step (b) is treated with hydrogen at a temperature in the 50 to 150 .degree.C range and a pressure in the 1.5 to 250 bar range in the presence of a hydration catalyst and, if desired, a solvent, to give a mixture A;(d1) mixture A is taken at a temperature in the 30 to 80 .degree.C range and a pressure in the 1 to 5 bar range over an ion exchanger containing acid terminal groups to give a mixture B1 or (d2) mixture A is distilled in the presence of sulphuric acid, in which any solvent is removed before the addition of the sulphuric acid to give a mixture B2; a nd (e) mixture B1 or B2 is distilled in the presence of a base to yield pure caprolactam.