Coupling Electrocatalytic CO₂ Reduction with Thermocatalysis Enables the Formation of a Lactone Monomer

Carbonylation reactions that generate high-value chemical feedstocks are integral to the formation of many industrially significant compounds. However, these processes require the use of CO, which is invariably derived from fossil-fuel-reforming reactions. CO may also be generated through the electroreduction of CO₂ , but the coupling of these two processes is yet to be considered. Merging electrocatalytic reduction of CO₂ to CO with thermocatalytic use of CO would expand the range of the chemicals produced from CO₂ . This work describes the development of a system coupling a high-pressure CO₂ electrolytic cell containing a bimetallic ZnAg catalyst at the cathode for production of CO with a reactor with a Faradaic efficiency of >90 % where high pressure CO is used for carbonylating propylene oxide into β-butyrolactone by thermal catalysis, the latter step having a reaction yield above 80 %. Although the production of monomers and polymers from CO₂ is currently limited to organic carbonates, this strategy opens up the access to lactones from CO₂ , for the formation of polyesters.