One-Pot Efficient Fixation of Low-Concentration Co2 into Cyclic Carbonate by Mesoporous Pyridine- Functionalized Binuclear Poly(Ionic Liquid)S

Abstract

The direct conversion of low-concentration CO2 from flue gas avoids the energy-intensive purification and concentration of CO2 to implement next utilization, making it undoubtedly a green process. However, achieving low concentration of CO2 cycloaddition with epoxide over functionalized poly(ionic liquids) catalyst and understanding the relevant mechanism at the molecular level are still challenging. Here, novel mesoporous pyridine-functionalized binuclear poly(ionic liquid)s (PB-PIL)s were successfully synthesized by the polymerization of DVB, basic monomers and binuclear ionic liquid monomers, regulating the density of pyridine sites and binuclear halogen counterions to achieve the optimum balance between the active sites and pore structure of copolymerized materials. Remarkably, PB-PILs were active in the cycloaddition reaction of the low-concentration CO2 (15% CO2 + 85% N2) without any co-catalyst and gave 95% yield of cyclic carbonate. Relied on DFT theoretical calculation, the activation degree of pyridine to CO2 and the promotion of CO2 insertion were deeply explored, providing more broad ideas for the conversion of low concentration carbon dioxide.

Keywords: Low-concentration CO2, Pyridine, Binuclear PILs, Mesopore, Cyclic carbonate