Acid-base bifunctional catalyst: Carboxyl ionic liquid immobilized on MIL-101-NH2 for rapid synthesis of propylene carbonate from CO2 and propylene oxide under facile solvent-free conditions

In terms of ‘green chemistry’ and ‘atom economy’, the cycloaddition of CO 2 to yield cyclic carbonate without any additive is an eco-friendly way to utilize CO 2 . Unfortunately, the low CO 2 capture quantity of common catalysts limited its catalytic efficiency. Herein, a novel acid-base bifunctional catalyst was successfully prepared by immobilizing ionic liquid on MIL-101-NH 2 (IL/MIL-101-NH 2 ) and tested for propylene carbonate (PC) rapid and facile synthesis from CO 2 and propylene oxide (PO). The synergetic interaction between Lewis base with strong CO 2 chemical capture capacity and Brønsted acid with strong hydrogen bond donor leads to the high catalytic efficiency of IL/MIL-101-NH 2 for carbonate synthesis from CO 2 and PO without any additive. The immobilization mode between MIL-101-NH 2 and IL is energetically supported by the density functional theory (DFT) calculations. This design idea of specific catalyst and the acid-base synergetic strategy provides new insights into the design of powerful catalyst systems for the CO 2 conversion.