DBU-Based Ionic Liquid Grafted SBA-15 Dual-Functional Catalyst for the Cycloaddition Reaction of CO2 and Epoxide

The development of novel catalysts for the synthesis of cyclic carbonates under mild conditions remains a challenge. Herein, we designed the strategy of immobilizing DBU-based ionic liquid on mesoporous SBA-15 (DBU@SBA-15), due to the cooperative effect between silanol and bromide anion, DBU@SBA-15 exhibits high CO2 catalytic performance under solvent-free and metal-free and additive-free conditions. Typically, the yield of chloropropene carbonate was close to 100% from the reaction of epichlorohydrin and CO2 within 12 h at 80 degrees C and 2 MPa. Notably, the product yield could achieve 64.8% even at ambient pressure, and DBU@SBA-15 was recycled four times without significant loss of catalytic activity. Additionally, DFT studies revealed that the nucleophilic effect and the strong hydrogen bond together promote the ring-opening of epoxides, which was consistent with the possible reaction mechanism proposed based on experiments. [GRAPHICS]