(473g) Impact of Acid Modified DBU-Based Ionic Liquids As Catalysts on Glycolysis of Poly (ethylene terephthalate)

Polyethylene Terephthalate (PET) is one of the most popular packaging materials available worldwide for beverages. Even though mechanical recycling of PET is widely used in industry, due to the lack of availability of purer recycle streams, less percentage of PET waste is currently being recycled. Due to the increase in the generation of post-consumer PET, alternate recycling methods such as glycolysis is of interest. Glycolysis uses an excess of ethylene glycol as a solvent and reagent in the presence of a catalyst to break the ester bond and depolymerize the PET into Bis (2- hydroxyethyl) terephthalate (BHET). This BHET can then be converted back into PET. The aim of this study is to develop a series of 1,8-diazabicyclo [5.4.0] undec-7- ene (DBU) based salts as catalyst for the glycolysis of PET. The catalysts were developed by combining the super base DBU and a series of acids such as succinic acid, azelaic acid, and pimelic acid. The impact of reaction time, and catalyst/PET and EG/PET ratios on the conversion of PET and yield of BHET were monitored. The newly developed catalyst’s effectiveness and selectivity in the production of oligomers and BHET were compared to DBU during glycolysis. Effect of the presence of the acid group on catalyst activity was studied. A possible reaction mechanism is proposed and confirmed using FTIR and NMR analysis. Finally, the catalysts’ recoverability and reusability will also be discussed.