Aspects of the Chemistry of Poly(ethylene Terephthalate). III. Transesterification of Dimethyl Terephthalate with Ethylene Glycol in the Presence of Various Catalytic Systems

Abstract
The transesterification of dimethyl terephthalate has been studied by measuring the amount of methanol formed as a function of time. The influence of various catalytic systems was investigated with regard to the nature and concentration of the metal ion and temperature. The order of decreasing activity was found to be Pb, Zn, Mn, Sn, Sb, Ti, and mixtures of Zn plus Pb and Zn plus Sb were found to be synergistic. The postulate that there is a correlation between the metal oxygen bond and the activity of the catalyst is discussed.