(Mg–Zn)–Al layered double hydroxide as a regenerable catalyst for the catalytic glycolysis of polyethylene terephthalate

Abstract

(Mg–Zn)–Al layered double hydroxide (LDH) was prepared by the coprecipitation method at low super saturation conditions. The prepared (Mg–Zn)–Al LDH was analyzed using XRD, FTIR, N2 adsorption–desorption, TGA and DSC, confirming the formation of pure LDH phase. The extent of polyethylene terephthalate (PET) degradation by the glycolysis process was studied using the prepared (Mg–Zn)–Al LDH. The glycolysis process was optimized in terms of catalyst concentration, temperature, time, ethylene glycol dosage. Under the optimal conditions of 1.0wt.% of catalyst with 20g of ethylene glycol (EG) in the presence of 2.0g of PET at 196°C after 3h of glycolysis, complete PET conversion was achieved and the yield of bis (2-hydroxyethyl) terephthalate (BHET) reached 75%.