Imidazolium‐Functionalized Ionic Hypercrosslinked Porous Polymers for Efficient Synthesis of Cyclic Carbonates from Simulated Flue Gas

Abstract The rapid growth of CO 2 emissions, especially from power plants, has led to the urgent need to directly capture and fix CO 2 in the flue gas after simple purification rather than energy‐intensive gas separation. Herein, imidazolium‐functionalized ionic hypercrosslinked porous polymers (HCPs) bearing adjustable surface groups were straightforwardly synthesized through co‐hypercrosslinking of benzylimidazole salts and crosslinker through Friedel–Crafts alkylation. Abundant microporosity and relatively high ionic moieties were obtainable in the ethyl‐group‐tethered ionic HCP, giving a remarkably selective CO 2 capture performance with a CO 2 uptake of 3.05 mmol g −1 and an ideal adsorbed solution theory (IAST) CO 2 /N 2 selectivity as high as 363 (273 K, 1 bar). This ionic polymer demonstrated high efficiency in the synthesis of cyclic carbonates from the coupling of various epoxides with the simulated flue gas (15 % CO 2 and 85 % N 2 ), giving high yields, large turnover numbers (up to 4800), and stable reusability under additive‐ and solvent‐free conditions.