The depolymerization of polyethylene terephthalate

The depolymerization of polyethylene terephthalate(PET) in supercritical methanol was carried out using a stainless stirred autoclave. PET was decomposed into its monomers, dimethyl terephthalate and small amounts of methyl-(2-hydroxyethyl) terephthalate, bis (hydroxyethyl) terephthalate, ethylene glycol and methanol. The reaction products were analyzed using high performance liquid chromatography and gas chromatography. The yield of dimethyl terephthalate and the degree of PET depolymerization was mainly depending on weight ratio of methanol to PET, temperature, dimethyl terephthalate yield and reaction time, whilst the pressure has insignificant influence when it is above the critical point of methanol. The Chinese market was investigated under the optimal depolymerization conditions are