A process is described for preparing purified caprolactam, comprising the steps
a) extraction of crude caprolactam, obtained from the Beckmann rearrangement of cyclohexanone oxime, with an organic extractant,
b) removal of the organic phase from step a),
c) distillative separation of the organic extractant from the organic phase from step b) giving rise to water-containing lactam extract, being preceded by addition of the distillative separation, aqueous alkali metal hydroxide solution in an amount of from 0 to 10 mmol/kg of caprolactam,
d) addition of 0 to 30 mmol of alkali metal hydroxide/kg of caprolactam to the water-containing lactam extract from step c),
e) distillative removal of water from the water-containing lactam extract treated with alkali metal hydroxide from step d),
f) freeing the caprolactam from step e) from by-products lower- and higher-boiling than caprolactam by distillation,
with addition in steps c) and d) together of at least 1.5 mmol of alkali metal hydroxide/kg of caprolactam.
描述了一种制备纯化己内酰胺的工艺,包括以下步骤:a)用有机萃取剂提取从
环己酮肟的Beckmann重排得到的粗己内酰胺,b)从步骤a)中去除有机相,c)蒸馏分离从步骤b)中的有机相中的有机萃取剂,形成含
水的内酰胺萃取物,在蒸馏分离之前加入蒸馏分离,量为0至10毫摩尔/千克己内酰胺的
水溶性碱
金属氢氧化物溶液,d)向来自步骤c)的含
水内酰胺萃取物中加入0至30毫摩尔/千克己内酰胺的碱
金属氢氧化物,e)从经碱
金属氢氧化物处理的含
水内酰胺萃取物中蒸馏除去
水,f)通过蒸馏从步骤e)中释放出低于和高于己内酰胺的副产物,步骤c)和d)中至少添加1.5毫摩尔/千克己内酰胺的碱
金属氢氧化物。