The synthesis of polyethylene from ethylene monomer can be achieved through two main processes: high-pressure free-radical polymerization LDPE and low-pressure coordination polymerization HDPE and LLDPE . The optimal temperature, pressure, and catalyst ratio depend on the specific process and desired properties of the final product.1. High-Pressure Free-Radical Polymerization LDPE :- Temperature: 150-300C 302-572F - Pressure: 1000-3000 atm 14,500-43,500 psi - Catalyst: Free-radical initiators, such as organic peroxides or azo compounds, are used in this process. The optimal concentration of the initiator depends on the desired molecular weight and reaction rate. Generally, a lower initiator concentration results in a higher molecular weight.2. Low-Pressure Coordination Polymerization HDPE and LLDPE :- Temperature: 60-100C 140-212F for HDPE and 80-120C 176-248F for LLDPE- Pressure: 10-50 atm 145-725 psi - Catalyst: Ziegler-Natta or metallocene catalysts are used in this process. The optimal catalyst ratio depends on the specific catalyst system and desired properties of the final product. Generally, a higher catalyst concentration results in a higher molecular weight and a narrower molecular weight distribution.It is important to note that the optimal conditions for the synthesis of polyethylene may vary depending on the specific reactor design, catalyst system, and desired properties of the final product. Therefore, it is crucial to conduct experiments and optimize the process parameters for each specific case.