Synergistic effects of hydroxyl and tertiary amine in the catalytic carbonatization of epoxides with CO2 at atmospheric pressure

Abstract

Fixation of carbon dioxide is a key issue for the sustainable synthesis of chemical compounds. A catalyst system for the preparation of cyclic carbonates by the fixation of carbon dioxide (CO₂) onto epoxides is presented. This system is designed for easy application due to the availability of the compounds on an industrial scale as well as moderate reaction conditions. Notably, it avoids the use of metal-halogen catalysts and instead employs a tertiary amine as the catalytic center, in conjunction with an alcohol acting as a hydrogen bond donor (HBD). The kinetics of the cycloaddition reaction between epoxides and CO₂ were thoroughly investigated using IR spectroscopy. Remarkably, optimization of the amino-to-alcohol group ratio and the amine structure was carried out to enhance the overall performance of the catalyst system showing a synergistic effect between the tertiary amine and the hydroxyl. Most notably, this entire process is conducted without the use of solvents and operates at ambient pressure, underscoring its significant ecological advantages.