Continuous-flow synthesis of cyclic carbonates with polymer-supported imidazolium-based ionic liquid (Im-PSIL) catalysts

Abstract

Carbon dioxide (CO₂), a major greenhouse gas emitted through human activities, represents a valuable carbon source for chemical production. However, maximizing its efficient utilization requires novel methods for CO₂ conversion that leverage the advantages of heterogeneous catalysis in continuous-flow systems. Herein, we report polymer-supported ionic liquids (PSILs) as efficient and recyclable catalysts for the continuous-flow synthesis of cyclic carbonates from epoxides and CO₂. We designed imidazolium-based PSIL catalysts specifically for this purpose. These catalysts demonstrated remarkable stability for over 160 h under continuous-flow conditions with gaseous CO₂, achieving an average yield of over 90% throughout the reaction. Furthermore, they exhibit broad applicability to 12 different epoxide substrates, yielding moderate to excellent yields. This work suggests an environmentally friendly pathway for the sustainable and scalable production of cyclic carbonates.