Catalytic Non-redox Carbon Dioxide Fixation in Cyclic Carbonates

Abstract

To stop global warming, we must introduce a variety of CO₂ reuse pathways. Redox chemistry is not trivial; reduction of CO₂ back to methane requires up to 8 electrons per molecule, leading to heavy energy demand. Non-redox paths have low energy needs and could provide a quick relief. A promising non-redox CO₂ product, cyclic carbonate is a versatile building block for green plastics and solvents. Although studies date back as early as 1969, no industrially viable process has since been introduced, mainly because of the lack of an effective catalyst for direct addition of CO₂ to the epoxides. Conceptually, the ideal catalyst should (1) be free of metals; (2) be free of co-catalysts; (3) be free of high pressure requirements; (4) provide quantitative selectivity to cyclic carbonate (5) provide a wide substrate scope, including very hard substrates; (6) provide reusability; and (7) be inexpensive. The imidazolinium catalyst that we developed herein addresses all 7 qualities and offers rapid implementation for CO₂ reclamation.