Co-upcycling of polyethylene terephthalate and polyoxymethylene into valuable chemicals

Abstract

The growing plastic pollution crisis calls for a greater focus on catalytic waste transformation. Among the plethora of plastics, polyethylene terephthalate (PET) is the most prevalent polyester, while polyoxymethylene (POM) is gaining traction as a widely utilized engineering plastic. In this study, we present a one-pot process for the simultaneous conversion of PET and POM plastic wastes with the use of a conventional acid catalyst. This process involves the condensation reaction of ethylene glycol (derived from PET) and formaldehyde (derived from POM), coupled with the prior depolymerization of PET and POM, resulting in the formation of 1,3-dioxolane and terephthalic acid as the major products. Notably, the catalytic reactions occur under mild conditions (no higher than 120°C) without the need for expensive catalysts or extreme environments, and all catalysts and solvents employed are recyclable. The proposed process could expand the application of waste PET and POM and inspire more upcycling strategies for plastic mixtures.