The optimal reaction conditions for the synthesis of polyethylene terephthalate PET from terephthalic acid and ethylene glycol involve a two-step process: esterification and polycondensation. 1. Esterification: In this step, terephthalic acid reacts with ethylene glycol to form bis 2-hydroxyethyl terephthalate BHET . The optimal reaction conditions for this step are: - Temperature: 220-260C - Pressure: Atmospheric pressure - Catalyst: Zinc acetate or titanium IV butoxide2. Polycondensation: In this step, BHET undergoes polymerization to form PET. The optimal reaction conditions for this step are: - Temperature: 270-290C - Pressure: Reduced pressure 0.1-1.0 mmHg to facilitate the removal of ethylene glycol by-product - Catalyst: Antimony trioxide Sb2O3 or titanium IV butoxideThese conditions should provide high yield and purity of polyethylene terephthalate. However, it is essential to note that the exact conditions may vary depending on the specific process and equipment used.