文献类型：期刊文献

英文题名：Polyoxometalate-based protic alkylimidazolium salts as reaction-induced phase-separation catalysts for olefin epoxidation

作者：Qiao, Yunxiang[1];Hou, Zhenshan[1];Li, Huan[1];Hu, Yu[1];Feng, Bo[1];Wang, Xiangrui[1];Hua, Li[1];Huang, Qingfa[1]

机构：[1]E China Univ Sci & Technol, Res Inst Ind Catalysis, Key Lab Adv Mat, Shanghai 200031, Peoples R China

年份：2009

卷号：11

期号：12

起止页码：1955

外文期刊名：GREEN CHEMISTRY

收录：;WOS:【SCI-EXPANDED(收录号:WOS:000272382200007)】；

基金：The authors are grateful for the support from the National Natural Science Foundation of China (No. 20773037), the Commission of Science and Technology of Shanghai Municipality (No. 07PJ14023), China. The authors would also like to express their thanks to Prof. Walter Leitner's helpful suggestion and Dr Nils Theyssen's assistance.

语种：英文

摘要：Two protic alkylimidazolium polyoxometalates, together with two corresponding aprotic N-methyl-alkylimidazolium polyoxometalates were synthesized and characterized by the methods of NMR, IR and TGA etc. Then, these salts were employed as catalysts for the epoxidation of cyclooctene in different media. The novel protic N-dodecylimidazolium peroxotungstate [HDIm](2)[{W=O(O-2)(2)}(2)(mu-O)] was found to be a room temperature liquid molten salt (ionic liquid) and the most effective catalyst for the epoxidation of cyclooctene among these salts. The ionic liquid catalyst [HDIm](2)[{W=O(O-2)(2)}(2)(mu-O)] can also be extended to the epoxidation of some other substrates. On the basis of this experimental observation, an efficient reaction-induced phase-separation catalyst system has been developed in this work. The reaction system can switch from tri-phase to emulsion and then to biphase and finally to all the catalyst self-precipitating at the end of the reaction, which made the recovery and reuse of the present catalyst very convenient.