A mathematical model for computer simulation of the production of unsaturated polyesters with catalysts

Abstract

A new method is described for following the polyesterification of propylene glycol with adipic acid or with maleic anhydride/adipic acid (70:30) by using p-toluensulphonic acid or zinc acetate as catalyst. This method is based on the volumetric measurement of the water produced during the polyesterification following appropriate heating programs. The kinetics of the reaction according to the measurements in the isothermal phases were examined; it was found that the reaction order was two in all cases and that the activation energy E and the frequency factor k o have lower values than in the case of the exclusive use of adipic acid, and also by using p-toluensulphonic acid as compared to the corresponding cases using zinc acetate. The values of E, k o and order consititute the fundamental parameters of a mathematical equation including also a correction factor Z (depending mainly on the heating rate). According to this equation, the water produced at various stages can be very well simulated. There are obvious applications of this method in connection with the automation for the industrial production of unsaturated polyesters by using a catalyst having the advantages of carrying out the reaction at lower temperatures and reduced total time in comparison with the corresponding non-catalyzed reaction.