Cyclic (Alkyl)(amino)carbene-Copper Supported on SBA-15 As an Efficient and Recyclable Catalyst for CO2 Hydrogenation to Formate

Recently, cyclic (alkyl)(amino)carbenes (CAACs) have been widely used as ligands to enhance the catalytic reactivity of center metal, but the problem of recycling this expensive ligand remains to be solved. In this work, the heterogeneous SBA-15-CAAC-Ir catalyst was prepared by a covalent attachment method, and using SBA-15 as the carrier. It shows high reactivity for the hydrogenation of CO2 to formate. After immobilization, the ordered mesoporous structure and the overall rod-like morphology of the original SBA-15 have been preserved very well. Using SBA-15-CAAC-Ir as catalyst, up to 21050 TON can be obtained at 60 degrees C. In addition, the catalyst can be separated easily by centrifugation, and the catalytic activity of SBA-15-CAAC-Ir can still remain very high after multiple cycles. (C) 2022 The Chemical Industry and Engineering Society of China, and Chemical Industry Press Co., Ltd. All rights reserved.