Chemical Recycling of Poly(Cyclohexene Carbonate) Using a Di-MgII Catalyst

Frances N Singer; Arron C Deacy; Thomas M McGuire; Charlotte K Williams; Antoine Buchard

doi:10.1002/anie.202201785

Chemical Recycling of Poly(Cyclohexene Carbonate) Using a Di-Mg^II Catalyst

Angew Chem Int Ed Engl. 2022 Jun 27;61(26):e202201785. doi: 10.1002/anie.202201785. Epub 2022 May 5.

Authors

Frances N Singer¹, Arron C Deacy², Thomas M McGuire², Charlotte K Williams², Antoine Buchard¹

Affiliations

¹ Department of Chemistry, University of Bath, Centre for Sustainable and Circular Technologies, Claverton Down, Bath, BA2 7AY, UK.
² Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Rd, Oxford, OX1 3TA, UK.

Abstract

Chemical recycling of polymers to true monomers is pivotal for a circular plastics economy. Here, the first catalyzed chemical recycling of the widely investigated carbon dioxide derived polymer, poly(cyclohexene carbonate), to cyclohexene oxide and carbon dioxide is reported. The reaction requires dinuclear catalysis, with the di-Mg^II catalyst showing both high monomer selectivity (>98 %) and activity (TOF=150 h^-1 , 0.33 mol %, 120 °C). The depolymerization occurs via a chain-end catalyzed depolymerization mechanism and DFT calculations indicate the high selectivity arises from Mg-alkoxide catalyzed epoxide extrusion being kinetically favorable compared to cyclic carbonate formation.

Keywords: Carbon Dioxide; Catalysis; Depolymerization; Epoxide; Recycling.

Abstract

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