Highly efficient CO2 fixation into cyclic carbonate by hydroxyl-functionalized protic ionic liquids at atmospheric pressure

Abstract We report an efficient strategy for CO2 fixation into cyclic carbonates catalyzed by hydroxyl-functionalized protic ionic liquids (PILs) without any solvent and additive. Excellent yields of cyclic carbonates are obtained for the varied substrates under mild conditions (1 bar and 60°C). Mechanism studies have shown that hydroxyl promoted the activation of epoxide molecules through hydrogen bonding interaction, so that CO2 can be easily converted into the desired product of cyclic carbonates. In addition, the hydroxyl-functionalized PILs can also be recycled repeatedly. This hydroxyl-functionalized PILs-catalyzed process is proved to be a promising scheme for the chemical conversion of CO2.