<p>Glycolysis of various PET waste materials reduces environmental threats and recovers the starting raw materials, which in turn accelerates the process of rapid and selective depolymerization of PET waste. This chemical recycling process is crucial for the circular economy of plastic waste. The conversion of PET is carried out with two different types of alcoholysis solvents (ethylene glycol and diethylene glycol) in the presence of a new catalytic system (zinc acetate with dimethyl aniline as co-catalyst), aiming to maximize the conversion and degradation of PET waste for high-yield production of intermediate monomers. The recovered raw materials were used as precursors to prepare unsaturated polyester resins with maleic anhydride and styrene monomers as reactive diluents. In this study, two different grades of polyethylene terephthalate (PET) waste materials were depolymerized through glycolysis to produce bis-hydroxyethyl terephthalate (BHET) using ethylene glycol (EG) or bis (2(2-hydroxy ethoxy) ethyl) terephthalate (BHDET) using diethylene glycol (DEG). The effects of reaction temperature, amount of co-catalyst, glycolysis time, and glycol/PET ratio on the conversion of PET waste materials and the isolated yield of intermediate monomers BHET and BHDET were investigated. FTIR, ¹H NMR, ¹³C NMR, GPC, DSC, and mechanical testing were used to characterize the properties of the reaction products in each step. It was found that the glycolysis of PET waste in the presence of a co-catalytic system proceeded faster than the zinc acetate-catalyzed reaction, as well as the unsaturated polyester resins synthesis.</p> Graphical abstract <p></p>