The synthesis of nylon-6,6 from adipic acid and hexamethylenediamine involves a condensation polymerization reaction, where water is eliminated as a byproduct. The optimum reaction conditions for this process are typically a temperature between 250-285C and a pressure of 1-5 atm.At these conditions, the reaction rate is increased, leading to a higher yield of nylon-6,6. The elevated temperature helps to overcome the activation energy barrier, allowing the reaction to proceed more efficiently. Additionally, the pressure range of 1-5 atm helps to maintain a suitable environment for the reaction to occur, as it is not too high to cause unwanted side reactions or too low to hinder the reaction rate.The reaction yield and purity of nylon-6,6 are affected by these conditions in the following ways:1. Temperature: Higher temperatures increase the reaction rate, leading to a higher yield of nylon-6,6. However, if the temperature is too high, it can cause thermal degradation of the polymer, resulting in a lower molecular weight and reduced mechanical properties. Therefore, it is essential to maintain an optimum temperature range to balance the reaction rate and product quality.2. Pressure: The pressure affects the reaction equilibrium and the rate of water removal from the reaction mixture. A higher pressure can help shift the equilibrium towards the formation of nylon-6,6, increasing the yield. However, if the pressure is too high, it can lead to unwanted side reactions and impurities in the final product. Therefore, maintaining a moderate pressure range is crucial for achieving a high yield and purity of nylon-6,6.In summary, the optimum reaction conditions for the synthesis of nylon-6,6 from adipic acid and hexamethylenediamine are a temperature between 250-285C and a pressure of 1-5 atm. These conditions help to achieve a high reaction yield and purity while minimizing the risk of thermal degradation and unwanted side reactions.