The synthesis of polyethylene terephthalate PET from terephthalic acid and ethylene glycol typically involves two main steps: esterification and polycondensation. The optimal reaction temperature and time for each step can vary depending on the desired molecular weight and physical properties of the final product.1. Esterification: In this step, terephthalic acid reacts with ethylene glycol to form bis 2-hydroxyethyl terephthalate BHET . The optimal reaction temperature for esterification is usually between 220-260C. The reaction time can range from 1 to 3 hours, depending on the desired degree of conversion.2. Polycondensation: In this step, BHET undergoes a condensation reaction to form PET. The optimal reaction temperature for polycondensation is typically between 270-290C. The reaction time can range from 2 to 4 hours, depending on the desired molecular weight and physical properties of the PET.It is essential to note that the optimal reaction conditions may vary depending on the specific catalysts, reactants, and equipment used in the synthesis process. Additionally, the intended application of the PET product may require adjustments to the reaction conditions to achieve the desired molecular weight and physical properties.