Synergistic Catalysis of Diverse Imidazolium Ionic Liquids and <scp>ZnO</scp> for Enhanced <scp>PET</scp> Glycolysis: A Sustainable Approach to Plastic Recycling

ABSTRACT The development of efficient catalytic systems for the glycolysis of PET is crucial for enhancing the recovery of valuable monomers from PET waste. In this study, a series of hybrid catalysts was prepared by combining imidazolium‐based ionic liquids (IL's) with zinc oxide (ZnO) nanoparticles for PET glycolysis. The IL–ZnO composites were synthesized using ultrasonication and examined under the same reaction conditions. Among the catalysts assessed, the [Amim][DCA]–ZnO hybrid exhibits the highest activity, achieving complete PET conversion and an 87.4% yield of bis(2‐hydroxyethyl) terephthalate (BHET) at 195°C within 60 min. Spectroscopic and microscopic analyses, supported by density functional theory (DFT) calculations, indicate that the enhanced performance arises from cooperative interactions at the IL–ZnO interface. Coordination of the [DCA] − anion to Lewis‐acidic Zn 2+ sites, together with non‐covalent interactions involving the imidazolium cation, facilitates polymer swelling and reduces the apparent activation energy to 67.8 kJ/mol. Differences in catalytic efficiency among the IL systems correlate with anion coordination strength and ionic liquid fluidity at the reaction temperature. A conceptual process scale‐up for PET glycolysis was evaluated using Aspen modeling. These results demonstrate that IL–ZnO hybrid catalysts provide a practical approach for PET glycolysis, supporting chemical recycling strategies aligned with circular economy principles.