公开(公告)号：IN172064B

公开(公告)日：1993-03-27

申请号：IN687MA1988

申请日：1988-10-04

Applicant: BASF AG

Inventor： GERALD NEUBAUER ,  EMILE DE DECKER ,  HUGO FUCHS ,  BERNHARD HOLZKNECHT ,  JOSEF RITZ

IPC: C07D201/16 ,  C07D223/00

Abstract: Caprolactam is recovered from caprolactam distillation low boilers or high boilers or mixtures thereof by the following steps: (a) crystallizing a low or high boiler or a mixture thereof to form purified capro-lactam crystals and a mother liquor, (b) separating off the purified caprolactam crystals to leave a mother liquor, (c) recycling from 5 to 90% by weight of the mother liquor of stage (b) into stage (a) and transferring the remainder of the mother liquor into the subsequent stage (d), (d) crystallizing the remaining mother liquor portion from stage (c) to form caprolactam crystals and a mother liquor, separating off the caprolactam crystals of stage (e) (d) and recycling the same into stage (a) to leave a mother liquor, (f) recycling from 20 to 99% by weight of mother liquor of stage (e) into stage (d) and channeling out the remainder of the impurity-containing mother liquor of stage (e).