Pyrrolidine-2,5-dione-derived ionic liquids promoted efficient transformation of flue gas CO2 into α-alkylidene cyclic carbonates at room temperature

The combination of pyrrolidine-2,5-dione-derived ionic liquids with silver acetate (AgOAc) were developed as binary catalysts for conversion of simulated flue gas CO 2 and propargylic alcohols to α-alkylidene cyclic carbonates. By tuning different catalyst components, the [HTMG][Pyrro]/AgOAc system was confirmed to be the most efficient and exhibited an excellent synergistic action in facilitating the carboxylic cyclization under room temperature and solvent-free conditions. The influence of reaction parameters on carboxylic cyclization of CO 2 with 2-methylbut-3-yn-2-ol were optimized. Under the determined conditions, the [HTMG][Pyrro]/AgOAc system was stable enough to show durable high activity in eight recycles, and also versatile in carboxylic cyclization of flue gas CO 2 with other propargylic alcohols. Moreover, a thorough comparison of [HTMG][Pyrro]/AgOAc with the reported catalysts was provided and evaluated, the results suggested that the developed catalytic system has significant advantages in practical application. Finally, the mechanistic details for the conversion of CO 2 into α-alkylidene cyclic carbonates catalyzed by [HTMG][Pyrro]/AgOAc was also elucidated on the basis of reactants activation. Binary [HTMG][Pyrro]/AgOAc system was developed for conversion of flue gas CO 2 into α-alkylidene cyclic carbonates at room temperature. • [HTMG][Pyrro]/AgOAc system is developed for direct CO 2 conversion from flue gases. • The system realizes ambient and clean synthesis of α-alkylidene cyclic carbonates. • [HTMG][Pyrro]/AgOAc system shows higher activity than most reported catalysts. • The catalytic system is easily separated and exhibits durable high-activity. • Detailed activation behaviors and synergistic catalytic mechanism are revealed.