The optimum reaction conditions for synthesizing nylon-6,6 from adipic acid and hexamethylenediamine are as follows:1. Temperature: The reaction is typically carried out at elevated temperatures, ranging from 250-285C. This temperature range allows for efficient removal of water, which is a byproduct of the reaction, and promotes the formation of the nylon-6,6 polymer.2. Pressure: The reaction is performed under atmospheric pressure or slightly above 1-2 atm to facilitate the removal of water and prevent the formation of side products.3. Reactant ratio: The stoichiometric ratio of adipic acid to hexamethylenediamine should be 1:1 to ensure the highest yield and quality of the nylon-6,6 product. This is because each adipic acid molecule reacts with one hexamethylenediamine molecule to form the nylon-6,6 polymer.In summary, the optimum reaction conditions for synthesizing nylon-6,6 from adipic acid and hexamethylenediamine are a temperature of 250-285C, a pressure of 1-2 atm, and a 1:1 reactant ratio. These conditions will help achieve the highest yield and quality of the nylon-6,6 product.