Zinc(II) porphyrin-based ionic porous organic polymers (iPOPs) having abundant dual-function sites for promoting cycloaddition of CO2 with epoxides

A series of zinc(II) porphyrin-based ionic porous organic polymers [ZnTPyPBr4/DVB(1:m)-iPOP (m = 10, 20, 30, 40)] were synthesized by the free-radical copolymerization of pyridinium-functionalized Zinc(II) porphyrin (ZnTPyPBr4) and divinylbenzene (DVB) through solvothermal method and characterized successfully. The iPOPs had high specific surface areas, relative high CO2 adsorption capacity, abundant dual-function sites (Zn and Br-) and high catalytic efficiency for the cycloaddition reaction of CO2 and epoxides under mild conditions (80 celcius, 0.5 MPa CO2). In particular, ZnTPyPBr4/DVB(1:30)-iPOP displayed the highest catalytic activity with a conversion of 99 % for the cycloaddition of CO2 and epichlorohydrin, wide applicability for different epoxides and could be recycled five times with almost no loss of activity. Notably, the kinetic experiments demonstrate that ZnTPyPBr4/DVB(1:30)-iPOP exhibited a low activation energy (22.64 kJ mol-1) for the cycloaddition reaction of CO2 and epichlorohydrin in the absence of solvent and cocatalyst.