Catalyst decomposition is achieved with the addition of an alcohol. The catalyst is not completely used in the polymerization process. The slurry solution is passed to a catalyst decomposition bed where the catalyst is deactivated. This type of polymerization is called slurry polymerization or suspension polymerization. Therefore, the polyethylene formed is in the solid phase. The melting point of high-density polyethylene is approximately 130 degrees Celsius. The solvent must not vaporize or react with any of the compounds in the reactor (inert solvent). The ethylene reacts with the active site of the catalyst to produce polyethylene. The boiling point of ethylene is approximately –100 degrees Celsius. Ethylene is introduced into the reactor vessel in the gas phase.

The pressure of the reaction vessel is between atmospheric and 20 atm. titanium tetrachloride) is reacted in a reaction vessel with a metal alkyl at a temperature between 100-130 degrees Celsius in the presence of a solvent. The following reactions show the initiation step that creates the active site for polymerization, and the propagation step for the production of polyethylene:Ī brief description of the Ziegler process will be explained in the following paragraph. Natta explained the mechanism by explaining that the reactive site of the catalyst is the Ti-C bond and not the Al-C bond formed during the initiation step. Because of this, the catalyst’s used today to create polyethylene and other types of polymers are referred to as the Ziegler-Natta catalyst. The catalyst created is very similar to the catalyst Ziegler created to produce high-density polyethylene. After creating the catalyst, Natta introduced propylene to create polypropylene. He created polypropylene by reacting an organometallic with a metal alkyl to create an active site for polymerization. Natta worked alongside Ziegler in a laboratory in Germany. Today, the theory put forth by Natta is most credibly believed. The question that persists is where the active site of the polymerization takes place. The mechanism of the reaction to create high-density polyethylene is still not fully understood today. How did this polymerization occur? The question is still debated today.

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