Tuning Ionic Liquid-Based Catalysts for CO 2 Conversion into Quinazoline-2,4(1 H ,3 H )-diones.

Carbon capture and storage (CCS) and carbon capture and utilization (CCU) are two kinds of strategies to reduce the CO 2 concentration in the atmosphere, which is emitted from the burning of fossil fuels and leads to the greenhouse effect. With the unique properties of ionic liquids (ILs), such as low vapor pressures, tunable structures, high solubilities, and high thermal and chemical stabilities, they could be used as solvents and catalysts for CO 2 capture and conversion into value-added chemicals. In this critical review, we mainly focus our attention on the tuning IL-based catalysts for CO 2 conversion into quinazoline-2,4(1 H ,3 H )-diones from o -aminobenzonitriles during this decade (2012~2022). Due to the importance of basicity and nucleophilicity of catalysts, kinds of ILs with basic anions such as [OH], carboxylates, aprotic heterocyclic anions, etc., for conversion CO 2 and o -aminobenzonitriles into quinazoline-2,4(1 H ,3 H )-diones via different catalytic mechanisms, including amino preferential activation, CO 2 preferential activation, and simultaneous amino and CO 2 activation, are investigated systematically. Finally, future directions and prospects for CO 2 conversion by IL-based catalysts are outlined. This review is benefit for academic researchers to obtain an overall understanding of the synthesis of quinazoline-2,4(1 H ,3 H )-diones from CO 2 and o -aminobenzonitriles by IL-based catalysts. This work will also open a door to develop novel IL-based catalysts for the conversion of other acid gases such as SO 2 and H 2 S.