The optimum reaction conditions for the synthesis of polystyrene from styrene monomer to yield a maximum percentage yield and molecular weight are as follows:1. Temperature: The ideal temperature range for the polymerization of styrene is between 60-120C. Higher temperatures can lead to faster reaction rates, but may also result in lower molecular weight polymers. A temperature of around 100C is often used to balance the reaction rate and molecular weight.2. Pressure: The polymerization of styrene is typically carried out under atmospheric pressure. However, in some cases, slightly elevated pressures e.g., 1-5 bar can be used to increase the reaction rate and improve the yield.3. Catalyst: The most common catalysts used for the synthesis of polystyrene are free-radical initiators, such as benzoyl peroxide BPO or azobisisobutyronitrile AIBN . The concentration of the initiator should be optimized to achieve the desired molecular weight and reaction rate. Typically, a concentration of 0.1-1 wt% based on the weight of styrene is used.4. Solvent: The polymerization of styrene can be carried out in bulk without solvent or in solution. When a solvent is used, it should be non-polar and inert, such as toluene or xylene. The use of a solvent can help control the reaction rate and molecular weight distribution.5. Inhibitors: To prevent premature polymerization during storage and handling of styrene, inhibitors such as tert-butylcatechol TBC or hydroquinone are often added. However, these inhibitors must be removed or neutralized before the polymerization process to ensure a high yield and molecular weight.6. Reaction time: The reaction time should be optimized to achieve the desired conversion and molecular weight. Typically, the polymerization of styrene takes several hours to complete.In summary, the optimum reaction conditions for the synthesis of polystyrene from styrene monomer are a temperature of around 100C, atmospheric pressure, the use of free-radical initiators as catalysts, and the optional use of a non-polar solvent. The reaction time, initiator concentration, and removal of inhibitors should be optimized to achieve the maximum percentage yield and molecular weight.