Melamine-based mesoporous organic polymers as metal-Free heterogeneous catalyst: Effect of hydroxyl on CO2 capture and conversion

The development of cost-effective heterogeneous catalytic system for the synthesis of organic carbonate from CO2 and epoxide is of great importance. A series of mesoporous organic polymers (MOP-0, MOP-1, MOP-2, and MOP-3) were prepared through facile one-pot polycondensation of commercially available, low-cost melamine and monoaldehydes. These MOPs represent a novel kind of metal-free, recyclable heterogeneous catalysts for the reaction of CO2 with epoxides to form cyclic carbonates through hydrogen-bonding interaction. Moreover, hydroxyl functionalities in MOPs show a critical effect on their performance in CO2 capture and conversion. The CO2 adsorption capacity of these MOPs can be significantly enhanced by increasing the -OH portions in MOPs. Particularly, by introducing -OH group into the MOP structure (MOP-3 vs. MOP-0), the CO2 adsorption capacity under 1 bar at 273 K can be increased by 39% from 82.4 mg g(-1) (MOP-0) to 114.4 mg g(-1) (MOP-3).