The optimal reaction conditions for synthesizing polyvinyl alcohol PVA from vinyl acetate monomer VAM involve a two-step process: the polymerization of VAM to polyvinyl acetate PVAc and the hydrolysis of PVAc to PVA.1. Polymerization of VAM to PVAc:Temperature: The optimal temperature for the polymerization of VAM to PVAc is typically in the range of 50-70C. Higher temperatures can lead to faster reaction rates but may also result in increased side reactions and lower molecular weight.Pressure: The polymerization of VAM is usually carried out under atmospheric pressure.Catalyst type: Free-radical initiators, such as azobisisobutyronitrile AIBN or benzoyl peroxide, are commonly used as catalysts for the polymerization of VAM.Catalyst concentration: The catalyst concentration can vary depending on the desired molecular weight and reaction rate. Generally, a concentration of 0.1-1 wt% based on VAM is used.2. Hydrolysis of PVAc to PVA:Temperature: The hydrolysis of PVAc to PVA is typically carried out at elevated temperatures, in the range of 60-90C. Higher temperatures can lead to faster hydrolysis rates but may also result in increased side reactions and degradation of the polymer.Pressure: The hydrolysis of PVAc is usually carried out under atmospheric pressure.Catalyst type: Alkaline catalysts, such as sodium hydroxide NaOH or potassium hydroxide KOH , are commonly used for the hydrolysis of PVAc to PVA.Catalyst concentration: The catalyst concentration can vary depending on the desired degree of hydrolysis and reaction rate. Generally, a concentration of 1-5 wt% based on PVAc is used.The reaction conditions can affect the yield and molecular weight of the resulting PVA:- Higher temperatures during the polymerization step can lead to lower molecular weight PVAc due to increased chain transfer and termination reactions.- Higher catalyst concentrations during the polymerization step can lead to higher molecular weight PVAc due to increased initiation and propagation reactions.- The degree of hydrolysis during the second step can affect the properties of the resulting PVA. A higher degree of hydrolysis results in a more hydrophilic and water-soluble PVA, while a lower degree of hydrolysis results in a more hydrophobic and less water-soluble PVA. The degree of hydrolysis can be controlled by adjusting the catalyst concentration and reaction time during the hydrolysis step.