METHOD OF CONTINUOUS PURIFICATION OF RAW CAPROLACTAM PREPARED BY REACTING 6-AMINOCAPRONITRILE WITH WATER Russian patent published in 2000 - IPC

FIELD: chemical industry. SUBSTANCE: process comprises separation of low-boiling and high-boiling components from raw caprolactam, hydrogenation followed by treatment in acid medium and distillation in alkaline medium. After separation of low-boiling and high-boiling components, raw caprolactam is treated with hydrogen at temperature from 50 to 150 C and pressure from 1.5 to 250 bar in the presence of hydrogenation catalyst and, optionally, solvent. The resulting mixture A is allowed to pass is solvent at temperatures form 30 to 80 C and pressure from 1 to 5 bar through ion exchanger containing acid groups to prepare mixture B1, or distilled in the presence of sulfuric acid. Prior to addition of sulfuric acid. Solvent is optionally removed to prepare mixture B2. Solvent is water. Mixture of B1 or B2 is distilled off in the presence of base to prepare pure caprolactam. EFFECT: increased yield and higher purity of the caprolactam. 2 cl, 1 tbl