The optimum reaction time and temperature for the synthesis of polyethylene terephthalate PET from terephthalic acid TPA and ethylene glycol EG depend on the specific process being used. Generally, the synthesis of PET from TPA and EG occurs in two main steps: esterification and polycondensation.1. Esterification: In this step, TPA reacts with EG to form bis 2-hydroxyethyl terephthalate BHET . The esterification reaction is typically carried out at temperatures between 240-260C. The reaction time for this step can range from 60 to 120 minutes, depending on the specific conditions and catalysts used.2. Polycondensation: In this step, BHET undergoes polymerization to form PET. The polycondensation reaction is typically carried out at temperatures between 270-290C under vacuum to remove the generated ethylene glycol. The reaction time for this step can range from 2 to 4 hours, depending on the desired molecular weight of the PET and the specific conditions used.The yield and molecular weight of the resulting PET polymer are affected by the reaction time and temperature:- Yield: Higher reaction temperatures and longer reaction times generally result in higher yields of PET. However, excessive reaction times and temperatures can lead to side reactions and degradation of the polymer, reducing the overall yield.- Molecular weight: The molecular weight of the PET polymer is directly related to the reaction time and temperature during the polycondensation step. Longer reaction times and higher temperatures result in higher molecular weights, as more BHET monomers are incorporated into the polymer chain. However, excessive reaction times and temperatures can also lead to degradation of the polymer, reducing the molecular weight.In conclusion, the optimum reaction time and temperature for the synthesis of PET from TPA and EG depend on the specific process and conditions used. Generally, esterification is carried out at temperatures between 240-260C for 60-120 minutes, while polycondensation is carried out at temperatures between 270-290C for 2-4 hours. These parameters affect the yield and molecular weight of the resulting PET polymer, with higher reaction times and temperatures generally resulting in higher yields and molecular weights, but also increasing the risk of side reactions and degradation.