The role of hydroxyl groups in poly(ionic liquid)s on <scp>CO₂</scp> cycloaddition with epoxides in the view of catalytic kinetics

Abstract The cycloaddition of CO 2 and epoxides can produce high‐value cyclic carbonates. This study developed a series of hydroxyl functional imidazolium‐based poly(ionic liquid)s (PILs) by copolymerization of ionic liquids ([HeVIM]Br or [BVIM]Br), 4‐vinylphenol, and divinylbenzene. The as‐synthesized PILs were investigated as catalysts for the cycloaddition of CO 2 with epichlorohydrin, and higher catalytic activity was observed over PILs with the cooperative activation effect between imidazolium and hydroxyl groups. The optimized PILs could achieve a 92.9% yield of cyclic carbonate in 2 h at 1.0 MPa CO 2 and 393 K, and a considerable cyclic carbonate formation rate of 1.7–2.8 h −1 at ambient reaction conditions (0.5 MPa CO 2 and 303 K). Kinetic experiments and theoretical calculations indicate that the presence of a hydrogen bond network lowers the energy barrier of the ring‐opening step in CO 2 cycloaddition, further facilitating the CO 2 conversion over imidazolium groups.