Heterogeneous Transfer Dehydrogenation for Catalytic Upcycling of Polyethylene

Polyethylene is the most widely produced plastic globally and a major component of plastic waste. In this work, a chemical recycling process is proposed, yielding telechelic macromonomers as useful building blocks for the polymer industry. Polyethylene was partially dehydrogenated using a reusable, heterogeneous platinum catalyst at moderate temperatures, employing ethylene as a convenient hydrogen acceptor. Various support materials and reaction conditions were investigated, with Pt/ZnO showing the best performance under a constant flow of ethylene. Dehydrogenated samples were subjected to olefin cross-metathesis with ethyl acrylate using a homogeneous Ru catalyst and then hydrogenated without additional catalyst. The final products, ester-terminated polyethylene macromonomers, have potential as building blocks for recyclable polyethylene-like materials and specialized block copolymers. The partially unsaturated polyethylene constitutes a versatile intermediate in the chemical recycling of polyethylene.