Zeolite catalyzed glycolysis of poly(ethylene terephthalate) bottle waste

Polyethylene terephthalate (PET) bottle waste was depolymerized using excess of ethylene glycol (EG) in the presence of zeolites, beta-zeolite and Y-zeolite as transesterification catalyst. The glycolysis reaction was carried out under reflux in excess of ethylene glycol LIP to 8 h. The product of glycolysis was mainly the virtual monomer, bis(2-hydroxyethyl) terephthalate (BHET) admixed with dimer as residue. The BHET was obtained in pure crystalline form. Influence of the reaction time, PET : EG ratio, type, and concentration of catalyst on the yield of the glycolysis products was investigated. The characterization of the purified monomer was carried out by elemental analysis, melting point, IR spectroscopy, DSC, and NMR. The yield of BHET monomer was more than 60%, which is comparable with the conventionally used heavy metal catalysts such as zinc acetate and lead acetate. This process of glycolysis of PET is economically viable and the catalysts are environment friendly. (c) 200 Wiley Periodicals, Inc.