A mathematical model for computer simulation of a direct continuous esterification process between terephthalic acid and ethylene glycol

Abstract

AbstractTo study the effect of potassium titanium oxyoxalate on the esterification reaction of terephthalic acid (TPA) and ethylene glycol (EG) in the first tank reactor of TPA/EG continuous esterification, experiments at various addition rates of potassium titanium oxyoxalate were made in the pilot plant. Potassium titanium oxyoxalate accelerated the esterification reaction of TPA and EG. Also, reaction rate constants of the reaction scheme reported in a previous report were fitted with the experimental results, and the calculated values of physical properties of oligomers obtained from these reaction rate constants showed relatively good agreement with experimentally obtained physical properties of the oligomers. The effect of potassium titanium oxyoxalate on the reaction rate constants was expressed by a set of seven equations: equation image Using the resultant reaction rate constants, the esterification reaction at various addition rates of potassium titanium oxyoxalate were stimulated and the following conclusions drawn: Under low pressure close to atmospheric, when the amount of water in the reaction mixture is very low, the decomposition of potassium titanium oxyoxalate proceeds slowly and decomposition can be practically neglected. Potassium titanium oxyoxalate accelerates the esterification reaction. Potassium titanium oxyoxalate mainly accelerates the main reactions and its effects on side reactions are rather weak. As a result, the higher the addition rate of potassium titanium oxyoxalate, the lower the values of AV and DEG, as is preferable.