Recent Advances on Imidazolium-Functionalized Organic Cationic Polymers for CO Adsorption and Simultaneous Conversion into Cyclic Carbonates.

The cycloaddition reaction of CO with various epoxides to generate cyclic carbonates is one of the most promising and efficient approaches for CO fixation. Typical imidazolium-based ionic liquids possessing electrophilic cations and nucleophilic halogen anions have been identified as excellent and environmentally friendly candidates for synergistically activating epoxides to convert CO . Therefore, the feasible construction of a series of imidazolium-functionalized organic cationic polymers can bridge the gap between homogeneous and heterogeneous catalysis, thereby obtaining highly selective CO adsorption and simultaneous conversion ability. This Review describes the recent advancements made with regard to the design and synthesis of this type of polymeric networks having imidazolium functionality. They are considered as an outstanding heterogeneous catalyst for the cycloaddition of CO to epoxides. Based on the perspective from the design of building blocks to the synthesis of cationic polymers, the focus mainly lies on how to introduce imidazole units into the material backbone via a covalent linking approach and how to incorporate other active sites capable of activating CO and/or epoxides into such polymeric materials.