文献类型：期刊文献

英文题名：Inclusion complexes of organic salts with β-cyclodextrin as organocatalysts for CO2 cycloaddition with epoxides

作者：Li, Kun[1];Wu, Xiaohui[1];Gu, Qingwen[1];Zhao, Xiuge[1];Yuan, Mingming[1];Ma, Wenbao[1];Ni, Wenxiu[1];Hou, Zhenshan[1]

机构：[1]East China Univ Sci & Technol, Sch Chem & Mol Engn, Res Inst Ind Catalysis, Key Lab Adv Mat, Shanghai 200237, Peoples R China

年份：2017

卷号：7

期号：24

起止页码：14721

外文期刊名：RSC ADVANCES

收录：;EI(收录号：20171103436854);WOS:【SCI-EXPANDED(收录号:WOS:000396150900049)】；

基金：The authors are grateful for support from the National Natural Science Foundation of China (21373082) and innovation Program of Shanghai Municipal Education Commission (15ZZ031), and the Fundamental Research Funds for the Central Universities.

语种：英文

外文关键词：Additives - Carbon dioxide - Organocatalyst

摘要：The inclusion complexes between beta-cyclodextrin (beta-CD) and the organic bases 1,8-diazabicyclo-[5.4.0] undec-7-ene (DBU)-based phenolates have been prepared by a simple method and also characterized by FT-IR, H-1 NMR, F-19 NMR, TGA etc. Among these inclusion complexes, DBU-based 2,3,4,5,6-pentafluorophenolate as a guest compound bound by beta-CD ([DBUH][PFPhO]/beta-CD) has been employed as an easily-separable organocatalyst for the cycloaddition of CO2 into cyclic carbonate and exhibited the best catalytic performance. High conversion of epoxides and excellent selectivity to carbonates could be achieved at 130 degrees C and under the 3.0 MPa CO2 without additional organic solvents or additives. Additionally, the organocatalyst [DBUH][PFPhO]/beta-CD exhibited the better recycability in consecutive catalytic recycles, as compared with that of corresponding DBU-based phenolates. The beta-CD played a crucial role in immobilizing catalytically active species and thus improving the recyclability of the present organocatalysts. The detailed characterization indicated that phenolate anions had been bound inside the cavity of beta-CD, while the [DBUH](+) cation was located outside of beta-CD. More interestingly, it was observed that phenolate anions could dissociate from the beta-CD cavity under the reaction temperature, but the inclusion compound could form on cooling the reaction mixture after reaction, which was extremely attractive for separation and recycling of the supramolecular organocatalysts. Finally, on the basis of the characterization above, a reaction mechanism for the present organocatalysts has been proposed.