2011•Journal of Chemical Engineering of Chinese UniversitiesRequires access
Liquid-Phase Beckmann Rearrangement of Cyclohexanone Oxime Catalyzed by Acidic Ionic Liquid-Zinc Chloride
Baoquan Zhang
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Abstract
The liquid-phase Beckmann rearrangement of cyclohexanone oxime was effectively realized to prepare e-caprolactam by using acidic ionic liquid-zinc chloride(IL-ZnCl2) catalytic system in acetonitrile.The only by-product,cyclohexanone,could convert back to the raw material,cyclohexanone oxime,by ammoximation reaction.The effects of solvents,reaction temperature,reaction time,the amount of IL,the amount of ZnCl2 on the Beckmann rearrangement were studied.The optimized conditions were:[HSO3-b-N(CH3)3]HSO4 0.5mmol,ZnCl2 15 mmol,acetonitrile 10 mL,cyclohexanone oxime 10 mmol,80℃,4 h.The conversation of cyclohexanone oxime can reach 100%,the yield of e-caprolactam can reach 94.9%.The reaction mechanism of cyclohexanone oxime rearrangement over IL-ZnCl2 catalyst was also investigated by React IR IC-10.