公开(公告)号：US3850910A

公开(公告)日：1974-11-26

申请号：US30172672

申请日：1972-10-30

Applicant: STAMICARBON

Inventor： GOETTSCH R ,  VOS H

IPC: C07D201/04 ,  C07D201/16 ,  C07D41/06

CPC classification number: C07D201/04 ,  C07D201/16

Abstract: 1. IN A PROCESS FOR THE RECOVERY PURE E-CAPROLACTAM CONTAINING LESS THAN 5 MEQ. OF IONOGENIC SUBSTANCES PER KG. OF LACTAM, OBTAINED BY INTRAMOLECULAR CONVERSION OF CYCLOHEXANONE OXIME WITH THE AID OF AN ACID CATALYST FROM THE GROUP CONSISTING OF SULFURIC ACID, OLEUM AND SULPHUR TRIOXIDE, AND EXTRACTION OF THE REACTION MIXTURE AFTER DILUTION WITH WATER AND, OPTIONALLY AFTER PARTIAL NEUTRALIZATION OF THE SULPHURIC ACID, WITH A WATER-IMMISCIBLE ORGANIC SOLVENT FOR THE LACTAM, THE IMPROVEMENT COMPRISING NEUTRALIZING THE RESULTING SOLVENT OF LACTAM IN THE ORGANIC SOLVENT WITH AQUEOUS AMMONIA TO A PH OF AT LEAST 4.5 (MEASURED AT 20* C.), THEREBY FORMING AN EMULSION OF AN AQUEOUS 15-40% WT. AMMONIUM SULPHATE SOLUTION EMULSIFIED IN THE ORGANIC SOLVENT, WASHING THE EMULSION WITH A COUNTERFLOW OF DEMINERALIZED WATER IN A WEIGHT RATIO OF 4-20 PARTS THEREBY REESTRACTING THE LACTAM FROM THE ORGANIC SOLVENT TO PRODUCE AN ECAPROLACTAM SOLUTION WITH LESS THAN 5 MEQ. OF IONOGENIC SUBSTANCES PER KG. OF LACTAM, WHILE THE RESULTING AQUEOUS LACTAM SOLUTION IS EVAPORATED, OPTIONALLY AFTER HAVING BEEN FREED OF ORGANIC IONGENIC COMPOUNDS ON CATION AND ANION EXCHANGERS.