Acetolysis of waste PET for upcycling and life-cycle assessment study

Abstract To reduce environmental pollution and reliance on fossil resources, polyethylene terephthalate (PET) as the most consumed synthetic polyester needs to be recycled effectively. However, the existing recycling methods cannot process colored or blended PET materials for upcycling. Here we report a new efficient method for acetolysis of waste PET into terephthalic acid (TPA) and ethylene glycol diacetate (EGDA) in acetic acid. Since acetic acid can dissolve or decompose other components such as dyes, additives, blends, etc., TPA can be crystallized out in a high-purity form. On the other hand, EGDA can be hydrolyzed to ethylene glycol or directly polymerized with TPA to form PET, completing the closed-loop recycling. The life-cycle assessment shows that, compared with the petroleum route, 67% of global warming potential and 77% of non-renewable energy use can be reduced via acetolysis under optimum conditions. This is the lowest environmental impact of all chemical recycling options available today.