Deep Eutectic Solvents as Efficient Catalysts for Fixation of CO2 to Cyclic Carbonates at Ambient Temperature and Pressure through Synergetic Catalysis

A series of deep eutectic solvents (DESs), consisting of protic ionic liquids (PILs) and amines, feature effective catalytic activity for the fixation of CO2 to cyclic carbonates at ambient temperature and pressure without any solvents and additives. Good yields of cyclic carbonates are achieved (up to 99%), and no obvious deactivation in catalytic activity is found after five cycles. Mechanistic research reveals that CO2 and epoxides are activated simultaneously through the synergistic catalysis of PILs and amines.