Process for preparing caprolactam and laurolactam.

摘要

There is disclosed a process for preparing caprolactam and laurolactam simultaneously by subjecting a mixture of cyclohexanone oxime and cyclododecanone oxime with a weight ratio of 40/60 to 70/30 to Beckmann rearrangement continuously in the presence of sulfuric acid and fuming sulfuric acid, under the conditions that amounts of the sulfuric acid and fuming sulfuric acid to be used in a rearrangement reaction solution are adjusted so as to satisfy the following formulae: 0.5 % by weight </= free SO3 concentration </= 4 % by weight and 1.2 < m </= 1.75 wherein m = (molar number of sulfuric acid + molar number of free SO3)/(molar number of cyclohexanone oxime + molar number of cyclododecanone oxime> and the rearrangement reaction is carried out at a temperature of 85 to 100 DEG C and a reaction time of 1 to 3 hours.