Modelling of the terephthalic acid - disodium terephthalate - sodium chloride - sodium hydroxide - ethylene glycol – water system

The Extended UNIQUAC electrolyte activity coefficient model was used for modeling the aqueous terephthalic acid, disodium terephthalate, sodium chloride, sodium hydroxide, ethylene glycol system. Data for solid-liquid equilibrium (SLE) and vapor-liquid equilibrium (VLE) was used for determining the parameters of the model. Model parameters were determined for terephthalic acid and for the terephthalate ion. Parameters for other species have previously been published and were used in this work. The modeling results are in close agreement with existing experimental data. It has an accurate outcome up to 90 °C based on available experimental measurements; however, the model predicts the reasonable performance of thermodynamics up to several hundred °C. Furthermore, this model can be used to perform simulation and process design of sustainable PET plastic recycling.