Metalloporphyrin Polymers with Intercalated Ionic Liquids for Synergistic CO₂ Fixation via Cyclic Carbonate Production

Abstract

Multifunctionalization of organic polymers for acting synergistically on substrate is of wide interest in the field of modern catalysis, but it is still a significant challenge. Herein, two novel bifunctional polymers were first designed and synthesized by combining ionic liquids (ILs) with zinc(II) porphyrin through simple and reversible Schiff base reactions. The fabricated polymers with flexible structures and nitrogen-rich environments presented high affinity toward CO2 molecules at ambient conditions. Owing to the cooperative nature of intercalated ILs and Lewis acidic metal sites, these materials could serve as efficient heterogeneous catalysts for the insertion of CO2 into epoxides to produce cyclic carbonates. As expected, these polymers exhibited good catalytic performance, robust constancy, excellent recyclability, and good substrate expansibility for this reaction in the absence of cocatalyst under mild or even ambient conditions. Notably, the selected catalyst SYSU-Zn@IL2 could directly convert diluted CO2 (15% CO2 in N2) into cyclic carbonate at 80 °C and 3.0 MPa, further offering the great application potential for recycling real-world carbon resource.