The synthesis of polyethylene from ethylene monomer using a Ziegler-Natta catalyst involves the following steps:1. Catalyst preparation: The Ziegler-Natta catalyst is typically a combination of a transition metal compound e.g., titanium tetrachloride, TiCl4 and an organometallic compound e.g., triethylaluminum, Al C2H5 3 . These two components are mixed together to form the active catalyst.2. Initiation: The organometallic compound reacts with the transition metal compound, resulting in the formation of an active catalyst site. An ethylene monomer coordinates to the active catalyst site, and the bond between the transition metal and one of the ligands e.g., a chloride ion is broken. This results in the formation of a metal-alkyl bond and the initiation of the polymer chain.3. Chain propagation: Additional ethylene monomers coordinate to the active catalyst site and insert themselves into the metal-alkyl bond, forming a longer polymer chain. This process continues, with each new ethylene monomer inserting itself into the metal-alkyl bond, until the polymer chain reaches the desired length.4. Chain termination: The polymer chain is terminated when the active catalyst site is deactivated, either by reacting with a terminating agent e.g., hydrogen or by transferring the growing polymer chain to another active catalyst site. The resulting polymer is then separated from the catalyst.The molecular weight of the resulting polyethylene can be influenced by several factors, including:1. Catalyst concentration: Higher catalyst concentrations can lead to a higher number of active catalyst sites, which can result in shorter polymer chains and lower molecular weights.2. Reaction temperature: Higher reaction temperatures can increase the rate of chain termination, leading to shorter polymer chains and lower molecular weights. Conversely, lower reaction temperatures can result in longer polymer chains and higher molecular weights.3. Reaction time: Longer reaction times can allow for more chain propagation, resulting in longer polymer chains and higher molecular weights. However, if the reaction is allowed to proceed for too long, the catalyst may become deactivated, leading to shorter polymer chains and lower molecular weights.4. Monomer concentration: Higher monomer concentrations can lead to faster chain propagation and longer polymer chains, resulting in higher molecular weights. Conversely, lower monomer concentrations can result in shorter polymer chains and lower molecular weights.5. Termination agents: The presence and concentration of termination agents can influence the molecular weight of the resulting polymer. Higher concentrations of termination agents can lead to shorter polymer chains and lower molecular weights, while lower concentrations can result in longer polymer chains and higher molecular weights.