Ionic Liquid/Zn-PPh3 Integrated Porous Organic Polymers Featuring Multifunctional Sites: Highly Active Heterogeneous Catalyst for Cooperative Conversion of CO2 to Cyclic Carbonates

A series of ionic liquid (IL), zinc halide (ZnX2), and triphenylphosphine (PPh3) integrated porous organic polymers (POPs) featuring multifunctional sites were afforded through solvothermal synthesis for cyclic carbonate synthesis which utilizes epoxides and carbon dioxide (CO2). Owing to the cooperative effect of ionic liquid and homogeneously distributed Zn-PPh3 specie, which is probably strengthened by the confined microporous structure and flexible frameworks, these POPs catalysts exhibited high CO2 capture and conversion performance and provided the highest activity (initial turnover frequencies up to 5200 h(-1)) of heterogeneous catalysts reported to date within the context of cyclic carbonate formation. Even more surprising, very favorable turnover numbers (TONs) of 2120 and 720 were attained at 40 and 25 degrees C, respectively. The effect of reaction parameters (reaction time, temperature, CO2 pressure) on the catalytic performance as well as other epoxide substrates were also investigated in detail. Furthermore, the catalyst can be easily recovered and reused five times without a significant loss of activity. These ionic liquid and Zn-PPh3 constructed porous polymers may provide an industrial opportunity for cyclic carbonate products.