Efficient chemical conversion of CO2 to cyclic carbonates on a functionalized zwitterionic polymer

Conversion of greenhouse gas carbon dioxide to valuable products is important to reach carbon balance and sustainability, of which catalytic cycloaddition of CO2 to cyclic carbonates has attracted much attention. Here, a biomass-derived zwitterionic polymer has been synthesized and characterized. The prepared polymer with porous structure was employed for the catalytic cycloaddition of atmospheric CO2 and epoxides in excellent yields with a broad substrate scope under solvent-, co-catalyst, and metal-free conditions. The synthesized polymer with good thermostability could be readily recovered and recycled four times at least. Moreover, this catalytic system provided satisfactory performance with up to 96% yield of cyclic carbonate even in the gram-level scale-up reaction under the optimal standard conditions. The catalytic mechanism has also been preliminarily discussed.