Theoretical–Experimental Study of the Release of Chlorine during the Synthesis of BHET in the Presence of PVC

Abstract

This work studies the chlorine (Cl) release during the esterification of terephthalic acid (TPA) and ethylene glycol (EG) due to the addition of different amounts of polyvinyl chloride (PVC) that emulates its presence as an impurity. With the aim to explore the possible effects of PVC presence and its dehydrochlorination during the syntheses of bis(2‐hydroxyethyl) terephthalate (BHET) and with the aid of a mathematical model, the evolution releasing of Cl during PVC dehydrochlorination is analyzed. Theoretical results present a good correlation with experimental data that indicate the presence of Cl in the composition of the final product because the dehydrochlorination is incomplete. Additionally, the model predicts the temperature in that Cl can be completely released avoiding its presence in BHET. These kinds of studies are of particular interest when products with a high degree of purity are required, and Cl is detrimental to end applications.