(154j) Selective and Efficient Glycolysis of Textile PET, Colored PET, and Multilayer PET Using Ionic Liquids

Chemical recycling of polyethylene terephthalate (PET) has gained significant attention due to the increasing concern over plastic waste pollution and the need for sustainable waste management practices. Among the various methods of advanced PET recycling, glycolysis has emerged as a promising approach. The importance of chemical recycling of PET by glycolysis lies in its potential to address the limitations of traditional mechanical recycling methods, such as contamination, color mismatch, and reduced mechanical properties. The role of catalysts in glycolysis of PET is critical, as they significantly improve the depolymerization process by accelerating the rate of reaction and reducing the reaction temperature. Catalysts can also enable the selective depolymerization of complex PET systems, allowing for the recovery of high-quality monomers for subsequent reuse in the production of new PET or other value-added chemicals. Ionic liquids (ILs) are a class of catalysts that can be tailored to have a specific chemical and physical properties including for use as recoverable catalysts. This study aimed to evaluate the efficiency of ILs based upon 1,8-diazabicyclo [5.4.0] undec-7-ene (DBU) in glycolysis of PET complex systems, including textile, colored, and multilayer PET. The approach involved depolymerizing the PET using glycolysis, with the assistance of the ILs. The resulting products were purified and re-polymerized to generate new PET. The study investigated the selectivity of ionic liquid catalysts towards the target reaction in production of the desired products and unwanted side products.