Catalytic Pyrolysis of Poly(Ethylene Terephthalate) in the Presence of Metal Oxides for Aromatic Hydrocarbon Recovery Using Tandem µ-Reactor-GC/MS

Poly(ethylene terephthalate) (PET) pyrolysis products and those produced from their subsequent catalytic reactions under various metal oxides (ZnO, MgO, TiO2, and ZrO2) were evaluated qualitatively and semiquantitatively using a tandem μ-reactor-gas chromatography-mass spectrometry (TR-GC/MS) system. The catalytic reaction products were analyzed in situ to determine the duration and temperature dependence of their production. In the TR-GC/MS, a reactor with two-tier, independent heat sources was linked directly to a GC/MS device. PET pyrolysis was carried out at 450 °C, whereas the pyrolysis products were reacted in the presence of metal oxides at 700 °C. ZnO, which has high base strength, promoted decarboxylation of the principal pyrolysis products of benzoic acid and terephthalic acid (TPA) selectively and at a low temperature. The proportion of oil components made up by benzene was up to 88.8 area%. On the other hand, MgO, TiO2, and ZrO2 have lower base strengths than ZnO. So, their capabilities for be...