Synthesis of cyclic carbonates by addition of CO2 to epoxides at atmospheric pressure

The fixation of carbon dioxide (CO 2 ) is a critical challenge for the sustainable synthesis of chemical compounds. This study presents a highly effective catalytic system for the synthesis of cyclic carbonates through the fixation of CO 2 on epoxides. The system is designed for ease of use, facilitated by the industrial-scale availability of the compounds and the moderate reaction conditions. The catalyst system employs tertiary amines in conjunction with halogenated alkali metal salts. Detailed kinetic studies of the cycloaddition reaction between epoxides and CO 2 were conducted using NMR spectroscopy. The reaction mechanism was thoroughly investigated and elucidated. The catalyst system demonstrates high efficacy with different kind of epoxides achieving high yields (>90 %) and high selectivity (>90 %). Notably, the entire process is conducted without solvents and at ambient pressure, highlighting its significant ecological benefits. Highly efficient catalytic system for the fixation of CO 2 into epoxides is based on a combination of alkali metal salts and tertiary amines. The synthesis is conducted at ambient pressure (1 bar) and without the use of solvents. • A catalytic system comprising a tertiary amine and halogenated alkali metal salts. • Facilitates the cycloaddition of CO₂ to epoxides with high yield and selectivity (>90 %). • The synthesis is performed at ambient pressure (1 bar) and does not require solvents. • Ionic liquid is formed in situ by reaction of epoxide, tertiary amine, and salt, which serves as the catalytic system. • Effective with different kind of epoxides.