The optimal reaction temperature and catalyst concentration for the synthesis of polyacrylonitrile PAN from acrylonitrile monomer using ammonium persulfate APS as the initiator can vary depending on the specific reaction conditions and desired properties of the resulting polymer. However, some general guidelines can be provided based on previous research and studies.1. Reaction Temperature: The polymerization of acrylonitrile using APS as the initiator is typically carried out at temperatures between 50-70C. Higher temperatures can lead to faster reaction rates, but may also result in lower molecular weight polymers and increased side reactions. A common temperature used in many studies is 60C, which provides a good balance between reaction rate and polymer properties.2. Catalyst Concentration: The concentration of APS initiator can also affect the reaction rate and properties of the resulting PAN polymer. A typical concentration range for APS in the polymerization of acrylonitrile is 0.5-2.0 wt% relative to the monomer. Lower concentrations may result in slower reaction rates and higher molecular weight polymers, while higher concentrations can lead to faster reaction rates and lower molecular weight polymers. A concentration of 1.0 wt% APS is often used as a starting point, and can be adjusted based on the desired reaction rate and polymer properties.It is important to note that these guidelines are not absolute, and the optimal reaction conditions may vary depending on the specific application and desired properties of the PAN polymer. It is recommended to perform a series of experiments to determine the best reaction temperature and catalyst concentration for your specific needs.