Selective epoxidation of cyclohexene to cyclohexene oxide catalyzed by Keggin-type heteropoly compounds using anhydrous urea–hydrogen peroxide as oxidizing reagent and acetonitrile as the solven

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• 作者：Ding ; Yong ; Gao ; Qiang ; Li ; Guixian ; Zhang ; Hanpeng ; Wang ; Jianmin ; Yan ; Liang ; Suo ; Jishuan
• 关键词：Epoxidation ; Cyclohexene ; Urea&ndash ; hydrogen peroxide ; Keggin-type heteropoly compounds ; Acetonitrile
• 刊名：Journal of Molecular Catalysis A ; Chemical
• 出版年：2004
• 期刊代码：57_13811169
• 类别：ch
• 出版时间：August 24, 2004
• 卷：218
• 期：2
• 页码：161-170
• 文件大小：159 K

摘要

The epoxidation of cyclohexene catalyzed by Keggin-type heteropoly compounds (HPAs) were investigated using anhydrous urea–hydrogen peroxide adduct (UHP) as an oxidant and acetonitrile as a solvent. Among a series of Keggin-type heteropoly compounds, tris(cetylpyridinium)12-tungstophosphate (CWP) showed the highest activity. By optimizing the reaction conditions, 80%conversion of cyclohexene and 97%selectivity for cyclohexene oxide could be achieved in the UHP/CH₃CN system. When aqueous 30%hydrogen peroxide (H₂O₂, HP) was used, the cyclohexene conversion and cyclohexene epoxide selectivity were inferior to those obtained with the UHP/CH₃CN system. The reaction of UHP with CWP has been studied by UV-Vis and ³¹P NMR spectroscopy, which has revealed that the Keggin-type heteropoly compounds CWP is degraded in the presence of excess UHP to form a considerable amount of phosphorus-containing species.