Restrictive Regulation of Quaternary Ammonium Salt Dropping into Sba-15 Pore Channel for Efficient Conversion of Carbon Dioxide

Abstract

The cycloaddition reaction of CO 2 and epoxides is an efficient way of carbon fixation. Herein, a new type of catalyst SBA-M based on a quaternization reaction was synthesized. The different amount of ionic liquid was added into SBA-15 by the post-grafting method, by which ionic liquid can been grafted into pore channel restrictively. SBA-Mn (0.2) with metal and halogen active sites into the pore channel shows exactly high PC (propylene carbonate) yield and selectivity for the wide range of epoxides under relative ambient conditions. Notably, SBA-Mn (0.2) has been demonstrated to maintain its catalytic activity and stability for over six cycles. Besides, we proposed a reaction mechanism for cycloaddition of CO 2 with epoxides by density-functional theory, showing that the metal is coordinated to oxygen atom of epoxide, and the halogen attacks the β carbon of epoxide. Moreover, the theoretical calculations and synthesis strategy shows great potential for CO 2 conversion.

Keywords: SBA-15, ionic liquid, Cycloaddition reaction, Immobilization, DFT