Effects of metal oxides on the pyrolysis of poly(ethylene terephthalate)

摘要

Metal oxides as Ca(OH)_2, NiO, Fe_2O_3 or TiO_2 showed different effects on the pyrolysis of PET. The experiments were carried out at 700℃ in a helium atmosphere using a laboratory equipment. Ca(OH)_2 led to the hydrolysis of the PET and the following dccarboxylation of the resulting terephthalic acid to benzene in a high amount up to 31 wt.%. By this means a yield of 77% related to the terephthalic acid content in the PET. The addition of Fe_2O_3 led to a similar but weaker effect. Nickel oxide showed less influence on the pyrolysis products of PET. With titanium dioxide considerably less gaseous products were obtained. When a mixture of Ca(OH)_2 and NiO was used PET was converted to synthesis-gas with a high hydrogen and carbon monoxide content and a gas amount of about 70%. The experiments with mixtures of Fe_2O_3 or TiO_2 with Ca(OH)_2 showed little differences to the experiments with pure Ca(OH)_2.