Abstract
Recent knowledge in chemistry has enabled the material utilization of greenhouse gas (CO2) for the production of organic carbonates using mild reaction conditions. Organic carbonates, especially cyclic carbonates, are applicable as green solvents, electrolytes in batteries, feedstock for fine chemicals and monomers for polycarbonate production. This review summarizes new developments in the ring opening of epoxides with subsequent CO2-based formation of cyclic carbonates. The review highlights recent and major developments for sustainable CO2 conversion from 2000 to the end of 2021 abstracted by Web of Science. The syntheses of epoxides, especially from bio-based raw materials, will be summarized, such as the types of raw material (vegetable oils or their esters) and the reaction conditions. The aim of this review is also to summarize and to compare the types of homogeneous non-metallic catalysts. The three reaction mechanisms for cyclic carbonate formation are presented, namely activation of the epoxide ring, CO2 activation and dual activation. Usually most effective catalysts described in the literature consist of powerful sources of nucleophile such as onium salt, of hydrogen bond donors and of tertiary amines used to combine epoxide activation for facile epoxide ring opening and CO2 activation for the subsequent smooth addition reaction and ring closure. The most active catalytic systems are capable of activating even internal epoxides such as epoxidized unsaturated fatty acid derivatives for the cycloaddition of CO2 under relatively mild conditions. In case of terminal epoxides such as epichlorohydrin, the effective utilization of diluted sources of CO2 such as flue gas is possible using the most active organocatalysts even at ambient pressure.
Highlights
Accepted: 4 March 2022Carbon dioxide capture and utilization (CCU technologies) has been recognized as a possible and cost-effective way to reduce worldwide greenhouse gas emissions [1–10].The use of CO2 as a raw material in chemical synthesis is a research area of great scientific, economic and ecological interest [1–14]
The nucleophile-based ring opening of oxirane activated by the catalyst with the subsequent addition of CO2 and five-membered ring closure accompanied by the release the utilization of metal-based catalysts is necessary for the direct formation of polycarbonates starting from CO2 and epoxides via ring-open6ing polymerization
The cyclic carbonate formation based on the cycloaddition of CO2 requires oxirane ring opening in the first reaction step, which is followed by insertion of CO2 in the second
Summary
Carbon dioxide capture and utilization (CCU technologies) has been recognized as a possible and cost-effective way to reduce worldwide greenhouse gas emissions [1–10]. Thering, nucleophile-based ring opening of oxirane activated by the catalyst with the subsequent addition of CO2 and five-membered ring closure accompanied by the release of nucleophile is described in Scheme 1, Path a. The catalytic carboxylation of epoxides may afford either cyclic carbonates (Scheme 2, Path a) or eventually polycarbonates (Scheme 2, Path b) [4,7,9], depending on the used catalyst and the reaction conditions. The nucleophile-based ring opening of oxirane activated by the catalyst with the subsequent addition of CO2 and five-membered ring closure accompanied by the release of nucleophile is described in Scheme 1, Path a. The nucleophile-based ring opening of oxirane activated by the catalyst with the subsequent addition of CO2 and five-membered ring closure accompanied by the release the utilization of metal-based catalysts is necessary for the direct formation of polycarbonates starting from CO2 and epoxides via ring-open6ing polymerization
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
