氯铝酸离子液体催化环己酮肟Beckmann重排制己内酰胺

Caprolactam prepared by Beckmann rearrangement of cyclohexanone oxime catalyzed by chloroaluminate ionic liquid

以氯铝酸离子液体作为催化剂和反应介质,通过实验研制一种价格低廉且环保的环己酮肟Beckmann重排制己内酰胺的催化体系.结果表明:环己酮肟转化率和己内酰胺选择性随离子液体酸性的增强而逐渐增大,离子液体中溶解的HCl对环己酮肟Beckmann重排的影响不大;反应温度、反应时间和离子液体用量对环己酮肟Beckmann重排有着较大的影响;确定离子液体Et3NHCl-2AlCl3催化环己酮肟Beckmann重排反应的最佳条件,反应温度为100℃,反应时间为60min,离子液体与环己酮肟摩尔比为1∶1;在该反应条件下,环己酮肟转化率为99.7%,己内酰胺选择性为98.0%,己内酰胺收率为97.8%.

In order to develop a cheap and environmental friendly catalytic system for Beckmann rearrangement of cyclohexanone oxime(CHO) to caprolactam(CPL),chloroaluminate ionic liquids were used as catalyst and reaction media.Both CHO conversion and CPL selectivity increased with increasing acidity of ionic liquids,and the dissolved HCl in ionic liquids showed little influence on Beckmann rearrangement of CHO.Reaction temperature,reaction time and ionic liquid dosage showed great influence on Beckmann rearrangement of CHO.The optimal reaction conditions of Beckmann rearrangement of CHO catalyzed by the ionic liquid Et3NHCl-2AlCl3 were determined.The optimal reaction temperature,reaction time and mole ratio of ionic liquid to CHO were 100 °C,60 min and 1∶1,respectively.Under the optimal reaction conditions,CHO conversion reached 99.7%,CPL selectivity was 98.0%,and CPL yield was 97.8%.