A mathematical model for computer simulation of a direct continuous esterification process between terephthalic acid and ethylene glycol: Part 1. Model development

Abstract

A new mathematical model has been developed for the continuous esterification process of terephthalic acid (TPA) and ethlene glycol (EG) with consideration of oligomer characteristics. The liquid weight fraction in the reaction mixture, β, has been selected as a principal parameter in this model. The solubility of TPA in EG and bis β‐hydroxyethyl terephthalate (BHET) has been measured in order to estimate more precisely the concentration of each component. Good agreement has been obtained by plotting the log of solubility data of TPA in EG and BHET against the reciprocal of the absolute temperature with correlation coefficients of 0.998 and 0.989, respectively. The validity of these data has been verified in comparison with other data.

A mathematical model for a continuous esterification process with recycle between terephthalic acid and ethylene glycol

“…( 4 ) ; for the formation of the DEG end group, two molecules are generated from eqs. (5) to ( 7 ) . An oligomer with the polymerization degree of P , comprises the polymer chains with the EG linkages of ( P , -1 ) / ( 1 + e ) and DEG linkages of ( P , -l ) e / ( 1 + e ) , and the bifunctional end groups with the carboxyl end groups of 2 ( 1 -4 ) and hydroxyl endgroups of 24; the hydroxyl end groups comprise of EG molecules of 24/( 1 + e ) and the DEG molecules of 24e/( 1 + e ) .…”

“…When the recycle ratio ( CYFB), 7 value, inlet heating medium temperature (tsi), and overall heat transfer coefficient ( V ) are given, from the reaction simulation results by eqs. (38) through (84), and the heat balances of eqs.…”

Effect of diantimony trioxide on direct esterification between terephthalic acid and ethylene glycol

“…6 It was found that the effect of Sb,O, on reaction rate constants are expressed as follows. In other words, it is understood that in this way the effect of Sb,O, on the continuous esterification of TPA and EG can be obtained with fair accuracy.…”

Solubility of terephthalic acid in the reaction system oligomeric bishydroxybutyl terephthalates—1,4‐butanediol

“…Similar to the reaction between TPA and ethylene glycol, the reaction between TPA and BD is heterogeneous [8], it can be assumed that the esterification occurs only in the liquid phase [9,10]. So the solubility of TPA in the liquid phase has a significant effect on the esterification rate.…”