摘要
研究了酮与环糊精手性协同催化作用下,用非手性酮与过氧硫酸氢钾(商品名Oxone)原位产生的二氧杂环丙烷实现了对包合在环糊精手性微反应器中苯乙烯的不对称环氧化反应,考察了α-环糊精、β-环糊精、γ-环糊精与不同的酮协同催化反应效果,并对协同催化反应机理进行了探讨.结果表明,β-环糊精和甲基异丁基酮(MIBK)及Oxone原位形成的二氧杂环丙烷具有较好的协同催化作用;MIBK用量、碳酸氢钠用量、反应时间和温度等因素对反应产物的收率和对映体选择性有一定的影响.在优化条件下,环氧苯乙烷的ee值可达46%.
The asymmetric epoxidation of styrene included by cyclodextrins with dioxirane produced in situ from ketones and potassium peroxymonosulfate （Oxone ） was achieved. The effects of different cyclodextrins and ketones on the epoxidation of styrene were investigated, and the possible mechanism for the synergistic catalysis of cyclodextrins and ketones was suggested. The results indicated that β-cyclodextrin had good ability of chiral recognition to dioxirane that was generated in situ from methyl isobutyl ketone （MIBK） and Oxone . Various factors, such as molar ratio of MIBK to cyclodextrin inclusion complex, NaHCO3 amount, reaction time, and reaction temperature, that affected the enantiometric excess of the reaction products were examined, and the maximum enantiometric excess of 1,2-epoxyethylbenzene was up to 46 % under the optimal reaction conditions.
出处
《催化学报》
SCIE
CAS
CSCD
北大核心
2007年第5期469-473,共5页
基金
湖南省自然科学基金(05JJ30024).
关键词
苯乙烯
环糊精
包合物
二氧杂环丙烷
环氧化
协同催化
环氧苯乙烷
styrene
cyclodextrin
inclusion complex
dioxirane
epoxidation
synergistic catalysis
epoxyethylbenzene
