Imidazolium-Based Deep Eutectic Solvents Catalyzed Cycloaddition Reaction of Epoxide with CO2 in Simulated Flue Gas

The development of catalytic systems capable of in situ capturing carbon dioxide (CO₂) from flue gas under ambient pressure and subsequently converting it into high-value chemicals holds significant practical importance for reducing atmospheric CO₂ levels and advancing the chemical industry. In this study, deep eutectic solvents (DESs) composed of an imidazolium salt and 3-aminobenzyl alcohol were synthesized and employed to catalyze the cycloaddition of CO₂ from simulated flue gas (15% CO₂ + 85% N₂) with epoxides. This catalytic system exhibited excellent catalytic activity, the yield of cyclic carbonate reached up to 94.3% upon reacting under simulated flue gas conditions at 55 °C and 1 atm for 24 h. The effects of temperature, reaction time and catalyst dosage on catalytic efficiency were investigated. The scope of various epoxides was also explored. Furthermore, the catalytic system is readily recyclable, maintaining nearly consistent catalytic activity over five cycles. The catalytic mechanism was clarified via FT-IR and NMR spectroscopic analyses, and a plausible cycloaddition reaction pathway was proposed.

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