The synthesis of polyvinyl chloride PVC from vinyl chloride monomer VCM is typically carried out through a polymerization process called suspension polymerization. The optimal reaction conditions and catalysts for this process are as follows:1. Temperature: The reaction temperature for PVC synthesis is usually maintained between 40-60C. Higher temperatures can lead to side reactions and degradation of the polymer, while lower temperatures can result in incomplete polymerization.2. Pressure: The pressure is generally kept at atmospheric pressure or slightly above, as the reaction is exothermic and generates heat. Maintaining a suitable pressure helps control the reaction rate and avoid excessive heat buildup.3. Initiator/Catalyst: The polymerization of VCM to PVC is initiated by free-radical initiators, which are typically organic peroxides or azo compounds. Common initiators include benzoyl peroxide, di-tert-butyl peroxide, and azobisisobutyronitrile AIBN . The initiator concentration is usually in the range of 0.01-0.1 wt% of the monomer.4. Reaction Time: The reaction time for PVC synthesis can vary depending on the desired molecular weight and degree of polymerization. Typical reaction times range from a few hours to 24 hours.5. Agitation: Proper agitation is essential for maintaining a uniform suspension of the polymer particles in the reaction medium. This helps ensure a consistent particle size distribution and prevents the formation of large aggregates.6. Inhibitors: Inhibitors such as hydroquinone or monomethyl ether of hydroquinone MEHQ are often added to the reaction mixture to prevent premature polymerization during storage and transportation of the monomer.The yield and purity of the PVC product are affected by these factors in the following ways:1. Temperature: Maintaining an optimal temperature ensures complete polymerization and minimizes side reactions, leading to a higher yield and purity of the PVC product.2. Pressure: Controlling the pressure helps regulate the reaction rate and heat generation, which in turn affects the yield and purity of the PVC.3. Initiator/Catalyst: The choice and concentration of the initiator can influence the reaction rate, molecular weight, and degree of polymerization of the PVC, ultimately affecting the yield and purity.4. Reaction Time: A longer reaction time can result in a higher degree of polymerization and yield, but may also increase the risk of side reactions and impurities.5. Agitation: Proper agitation ensures a uniform particle size distribution and prevents the formation of large aggregates, which can affect the yield and purity of the PVC product.6. Inhibitors: The use of inhibitors helps prevent premature polymerization, ensuring a controlled reaction and a higher yield and purity of the PVC product.