KINETIC-MODEL FOR THE HOMOGENEOUSLY CATALYZED POLYESTERIFICATION OF DICARBOXYLIC-ACIDS WITH DIOLS

A generally applicable stoichiometric and kinetic model was developed for the polyesterification of unsaturated dicarboxylic acid with diols in the presence of a homogeneous acid catalyst. The model also incorp orates, besides the esterification, the cis-trans isomerization and th e double-bond saturation reactions. Rate equations based on plausible mechanistic reaction steps were derived, and the parameters of the rat e equations were determined with nonlinear regression analysis using t he polyesterification of maleic acid with propylene glycol at 150-190 degrees C as a demonstration system. Comparisons of the model predicti ons with the experimental data showed that the approach is useful in p redicting the polyesterification kinetics and the product distribution .