The optimal reaction temperature and time for the synthesis of nylon-6,6 from adipic acid and hexamethylenediamine to achieve maximum yield and purity typically involve a two-step process: the formation of nylon salt hexamethylene adipamide salt and the polymerization of the nylon salt.1. Formation of nylon salt:This step is usually carried out at room temperature around 25C with a stoichiometric ratio of adipic acid and hexamethylenediamine. The reaction time for this step is relatively short, typically ranging from a few minutes to an hour, depending on the concentration of the reactants and the efficiency of mixing.2. Polymerization of nylon salt:The polymerization step is carried out at elevated temperatures, typically between 250C and 285C, under a nitrogen atmosphere to prevent oxidation. The reaction time for this step can vary depending on the desired molecular weight and degree of polymerization. Generally, the reaction time ranges from 2 to 4 hours for a high degree of polymerization.It is important to note that the optimal reaction conditions may vary depending on the specific setup and equipment used in the synthesis process. Therefore, it is recommended to perform a series of experiments to determine the best conditions for a particular system.