Construction of pyridine-based porous ionic polymers with rich multifunctional sites for efficient CO2 cycloaddition

In this study, a sequence of pyridine-based hypercrosslinked ionic polymers (HIP-IBy, HIP-IByCA and HIP-IByBA) as heterogeneous catalysts were prepared using a two-step method for the CO2 cycloaddition reaction. The synthesized pyridine-based HIPs exhibit rich and uniform mesoporous structures, and abundant nucleophilic halide ions and hydrogen bond donors are successfully integrated into the HIPs skeleton. The prepared catalysts show the superior CO2 selective adsorption performance. In addition, the optimal catalyst HIP-IByBA(1:2) exhibits an excellent catalytic activity for the CO2 cycloaddition without the metals, cocatalysts and solvents. Especially, under the mild condition (70 degrees C, 1.0 MPa), the catalyst HIP-IByBA(1:2) also maintains a satisfactory catalytic performance, effectively capturing dilute CO2 (85 %N2/15 %CO2) and converting it into cyclic carbonates. The excellent catalytic activity as well as good recyclability and substrate universality makes prepared pyridine-based HIPs promising heterogeneous catalysts for CO2 cycloaddition reactions.