Ionic Polymer Microspheres Bearing a CoIII–Salen Moiety as a Bifunctional Heterogeneous Catalyst for the Efficient Cycloaddition of CO2 and Epoxides |
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| Authors: | Prof?Dr Yan Leng Dan Lu Chenjun Zhang Prof?Dr Pingping Jiang Weijie Zhang Prof?Dr Jun Wang |
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| Affiliation: | 1. The Key Laboratory of Food Colloids and Biotechnology, Ministry of Education, School of Chemical and Material Engineering, Jiangnan University, Wuxi, P. R. China;2. State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemistry and Chemical Engineering, Nanjing Tech University, Nanjing, P. R. China |
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| Abstract: | We report a unique strategy to obtain the bifunctional heterogeneous catalyst TBB‐Bpy@Salen‐Co (TBB=1,2,4,5‐tetrakis(bromomethyl)benzene, Bpy=4,4’‐bipyridine, Salen‐Co=N,N’‐bis({4‐dimethylamino}salicylidene)ethylenediamino cobalt(III) acetate) by combining a cross‐linked ionic polymer with a CoIII–salen Schiff base. The catalyst showed extra high activity for CO2 fixation under mild, solvent‐free reaction conditions with no requirement for a co‐catalyst. The synthesized catalyst possessed distinctive spherical structural features, abundant halogen Br? anions with good leaving group ability, and accessible Lewis acidic Co metal centers. These unique features, together with the synergistic role of the Co and Br? functional sites, allowed TBB‐Bpy@Salen‐Co to exhibit enhanced catalytic conversion of CO2 into cyclic carbonates relative to the corresponding monofunctional analogues. This catalyst can be easily recovered and recycled five times without significant leaching of Co or loss of activity. Moreover, based on our experimental results and previous work, a synergistic cycloaddition reaction mechanism was proposed. |
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| Keywords: | bifunctional catalysts carbon dioxide fixation CoIII– salen complexes cycloaddition ionic polymers |
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