Solventless, ambient-pressure production of bio-based lactones over earth-abundant, mixed metal oxide catalysts for circular polyesters.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41690923.
- Also identified by DOI 10.1038/s41467-026-69362-8 and PMC identifier 13021922.
- Licence recorded as CC BY-NC-ND.
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Abstract
Transitioning to a circular plastics economy will require use of renewable feedstocks, energy-efficient processes, and closed-loop recyclable polymers, such as polyesters. A key challenge lies in sustainably sourcing monomers used to make recyclable polyesters. This work presents a catalytic platform utilizing earth-abundant Cu<sub>(x)</sub>Ca<sub>(1-x)</sub>O mixed metal oxides for the oxidative dehydrocyclization of bio-based diols to lactones, which are advantaged for energy-efficient ring-opening polymerization. Operating below 200 °C, at ambient pressure, and without solvent, the process uses air as the sole oxidant, achieving high yields of lactones across a broad substrate scope of C<sub>4-8</sub> diols in the liquid phase. The oxidative dehydrocyclization reaction is thermodynamically downhill due to water formation and energy-efficient compared to incumbent, non-redox pathways utilized in fossil carbon-based industrial processes for lactone production. Mechanistic studies reveal facile redox cycling of Cu<sup>2+</sup>-O(Ca<sup>2+</sup>)-Cu<sup>2+</sup> interfacial sites unique to the developed catalyst. Techno-economic analysis and life cycle assessment estimate 40% lower energy demand and 15% lower GHG intensity per mass of butyrolactone produced compared to the fossil carbon-based route. Liquid-phase oxidative dehydrocyclization offers a promising approach for scalable lactone production from renewable, bio-based diols to enable circular polyesters.