METHOD FOR THE PRODUCTION OF PURIFIED CAPROLACTAM FROM THE BECKMANN REARRANGEMENT OF CYCLOHEXANONE OXIME

摘要

The present invention is a method for preparing purified caprolactam, a) extracting crude caprolactam obtained from Beckmann rearrangement of cyclohexanone oxime with an organic extracting agent, b) separating the organic phase from step a), c) A distillation separation step in which an organic extractant is distilled off from the organic phase of step b) to obtain a hydrous lactam extract, in which an aqueous alkali metal hydroxide solution is added in an amount of 0 to 10 mmol/kg of caprolactam prior to the distillation separation. Phosphorus phase, d) adding 0 to 30 mmol of alkali metal hydroxide per kg of caprolactam to the hydrous lactam extract of step c), e) distilling water from the hydrous lactam extract treated with an alkali metal hydroxide of step d), f) removing by distillation from the caprolactam of step e) a by-product having a boiling point lower and a higher boiling point than caprolactam It includes, and in steps c) and d) to add a total of 1.5 mmol or more alkali metal hydroxide per kg of caprolactam, it provides a method for producing a purified caprolactam.