Upcycling PET waste into high value-added p-xylylenediamine (PXDA): A route to diversify PET-derived chemicals

The upcycling of polyethylene terephthalate (PET) waste into value-added chemicals is of great interest. However, the diversity of currently accessible PET-derived high-value products remains limited, posing a significant challenge to expanding their scope. Herein, we report a three-step catalytic process for converting PET waste into p-xylylenediamine (PXDA)—an essential monomer for producing high-market-value polyamides, polyimides, and nonisocyanate polyurethanes. Specifically, PET is first transformed into terephthalamide (TP) via ammonolysis, and subsequently dehydrated to terephthalonitrile (TPN), the key intermediate for PXDA synthesis. Successful separation of each intermediate ensures efficient hydrogenation of TPN to PXDA, achieving an overall PXDA yield of 54.5 % from PET. Furthermore, the transformation of common real plastic waste and scale-up experiments demonstrate the robustness and substantial industrial potential of this catalytic route. This study establishes a viable and promising strategy for upcycling PET waste into high value-added product PXDA, significantly broadening the scope of PET-derived chemicals and stimulating further exploration of other valuable derivatives.