(154af) Polymer-Based Catalyst for Efficient Glycolysis of Poly (ethylene terephthalate) (PET)

Glycolysis is one of the advanced recycling methods for Polyethylene Terephthalate (PET) that can handle feedstock not recycled by mechanical recycling. It has the potential to create a more sustainable future for PET fibers used in clothing. Glycolysis reaction involves breaking down of the PET in excess ethylene glycol into Bis (2- hydroxyethyl) terephthalate (BHET), which can further be converted into PET. Glycolysis typically requires the use of a catalyst to break down the PET polymer into its constituent monomers. Since catalysts are crucial to the glycolysis process, it is important to recover them efficiently for reuse. This study aims to develop a catalyst for glycolysis of PET that does not require extensive and expensive recovery techniques such as distillation. We developed a catalyst by combining a polymeric acid (polyacrylic acid) and a super base 1,8-diazabicyclo [5.4.0] undec-7- ene (DBU) and investigated its effectiveness and selectivity. The impact of reaction time, temperature, catalyst/PET, and EG/PET ratios on PET conversion and BHET yield were monitored. Ultrafiltration method was used to selectively separate the polymer-based catalyst from other components of the reaction mixture, in order to recover and reuse. A reaction mechanism for glycolysis of PET using polymer-based catalyst was proposed and confirmed by FTIR and NMR methods.