The synthesis of high molecular weight polyethylene oxide PEO from ethylene oxide EO monomer using a basic catalyst typically involves anionic ring-opening polymerization. The optimum reaction conditions for this process are as follows:1. Temperature: The reaction temperature should be maintained between 50-100C. Higher temperatures can lead to side reactions and chain transfer reactions, which can reduce the molecular weight of the resulting PEO. Lower temperatures can slow down the reaction rate.2. Pressure: The reaction is typically carried out under atmospheric pressure. However, it can also be performed under slightly elevated pressure up to 5 bar to improve the solubility of the ethylene oxide monomer in the reaction medium.3. Catalyst concentration: The concentration of the basic catalyst, such as potassium alkoxide e.g., potassium tert-butoxide , should be kept low, typically in the range of 0.1-1.0 mol% relative to the ethylene oxide monomer. Higher catalyst concentrations can lead to a faster reaction rate but may result in lower molecular weight PEO due to increased chain transfer reactions.4. Initiator: In addition to the basic catalyst, an initiator is often used to start the polymerization reaction. Common initiators include alcohols, such as methanol or ethanol. The concentration of the initiator should be kept low, typically in the range of 0.1-1.0 mol% relative to the ethylene oxide monomer.5. Solvent: The reaction is typically carried out in an aprotic solvent, such as toluene or tetrahydrofuran THF , to prevent side reactions and ensure good solubility of the reactants and products.By carefully controlling these reaction conditions, it is possible to synthesize high molecular weight polyethylene oxide with a narrow molecular weight distribution.