Task-Specific Ionic Liquids Catalysts Efficiently Catalyze Atmospheric CO2 Gas Mixture to Cyclic Carbonates Under Mild Conditions

The conversion of atmospheric carbon dioxide (CO2) gas mixtures and epoxides to cyclic carbonates is an environmentally beneficial execution strategy, which is a useful platform chemical. However, this reaction is overly dependent on harsh reaction conditions including temperature and/or CO2 pressure in the traditional conversion process. We report a series of facilely prepared functionalized ionic liquids (ILs) for the one-pot synthesis of styrene carbonate (SC) from pure/diluted CO2 with styrene oxide (SO). Which achieved a yield up to 99% under atmospheric CO2 conditions. In addition, with the assistance of a small amount of catalyst, the product yield remained at 99% under diluted CO2 conditions. This result demonstrates that functionalized ILs could effectively catalyze the cycloaddition reaction of low-pressure CO2 without any co-catalysts such as metals, organic solvents, and active additives. The density functional theory (DFT) calculations combined with experimental results revealed that the highest catalytic ability of Cat.2 was ascribed to the synergic catalysis between positive charge delocalized cations and Br- anions to efficiently activate the substrates. Furthermore, the best ILs catalyst can be reused five times without significant reduction in catalytic activity, which shows its great potential for chemical conversion of atmospheric CO2.