Metaboric acid-catalyzed synthesis of cyclic carbonates from epoxides and CO2

Carbon dioxide stands out as the most prevalent greenhouse gas on Earth, presenting itself as not only abundant but also as a resource that is inexpensive, and renewable.Consequently, extensive research has been conducted on the conversion of CO2, with particular emphasis on the cycloaddition reaction involving CO2 and epoxides, resulting in the formation of cyclic carbonates.In this study, we report a metaboric acid/tetrabutylammonium bromide system for catalyzing the cycloaddition reaction.Employing HBO2 (1.25 mol %) and tetrabutylammonium bromide (3 mol %) as catalysts, the cycloaddition reaction between 4-vinylcyclohexene oxide and CO2 exhibited exceptional efficiency, yielding a 96% yield in 5 hours at 140 C under 14 bar pressure in solvent-free conditions.Notably, this catalytic system exhibited commendable efficacy in facilitating cycloaddition reactions with various mono-and disubstituted epoxides.