Conductometric measurement technique has been deployed to study the kinetic behavior during the reaction of poly(ethylene terepthalate) (PET) and NaOH. A laboratory made arrangement with facility of continuous stirring was used to carry out experiments at desired temperature. With conductometry, the determination of kinetic as well as thermodynamic parameters becomes more simple and faster as compared to gravimetry. Chemical kinetics of this reaction shows that it is a second order reaction with reaction rate constant ？g？1？s？1 at 70°C. The specific reaction rates of the saponification reaction in the temperature range at various temperatures (50–80°C) were determined. From the data, thermodynamic parameters such as activation energy, Arrhenius constant (frequency factor), activation enthalpy, activation entropy, and free energy of activation obtained were 54.2？KJ？g？1, ？min？1, 90.8？KJ？g？1, 126.5？JK？1？g？1, and 49.9？KJ？g？1, respectively. 1. Introduction The saponification of poly(ethylene terephthalate) (PET) is one of the known reactions in polymer chemistry and it is represented as an example of pseudofirst order in the literature dealing with chemical kinetics [1, 2]. This reaction has been studied by several investigators at different temperatures using different techniques and reagents. Alcoholysis has been carried out by different workers [3–9]. Hydrolysis of PET gives terephthalic acid (TPA) and ethylene glycol (EG) as a reaction product [10–13]. Aminolysis and methanolysis [14–16] give dimethyl terephthalate (DMT) and terephthalamide as a reaction product. Acid alkali and water hydrolysis of PET waste in organic solvent have been reported by several workers [17–21]. Kinetics of a phase transfer catalyzed alkaline hydrolysis of PET has been studied by Kosmidis et al. [22, 23]. They have used trioctylmethylammonium bromide as phase transfer catalyst. The method is useful because, nowadays, terephthalic acid is replacing dimethyl terephthalate as the main monomer in the industrial production of PET. Chemical recycling of PET has been carried out by Karayannidis and Achilias [24]. They found an effective way for production of secondary value-added materials. Alkaline hydrolysis of PET belongs to relatively frequently investigated reactions. Most often, the course of reaction is studied by gravimetry in withdrawn samples. The error in the kinetic and thermodynamic parameters are more in gravimetry as compared to conductometry. Another disadvantage of this method is high Inplace of labouriosity change time and considerable consumption of chemicals.
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