Efficient and Selective Chemical Recycling of CO 2 -Based Alicyclic Polycarbonates via Catalytic Pyrolysis.

Chemical recycling of polymers to their constituent monomers is the foremost challenge in building a sustainable circular plastics economy. Here, we report a strategy for highly efficient depolymerization of various CO 2 -based alicyclic polycarbonates to epoxide monomers in solvent-free conditions by a simple Cr III -Salen complex mediated catalytic pyrolysis process. The chemical recycling of the widely studied poly(cyclohexene carbonate) exhibits excellent reactivity (TOF up to 3000 h -1 , 0.1 mol % catalyst loading) and high epoxide monomer selectivity (>99 %). Mechanistic investigation reveals that the process proceeds in a sequential fashion via a trans-carbonate intermediate.