The most efficient catalyst for the synthesis of polypropylene from propylene monomer is the Ziegler-Natta catalyst. Ziegler-Natta catalysts are a class of organometallic catalysts that consist of a transition metal compound usually titanium, vanadium, or zirconium and an organoaluminum compound usually an alkyl aluminum compound . The most common Ziegler-Natta catalyst used for polypropylene synthesis is a combination of titanium trichloride TiCl3 and triethylaluminum Al C2H5 3 .The concentration of the Ziegler-Natta catalyst in the polymerization reaction affects the yield and properties of the resultant polypropylene. The catalyst concentration has a direct impact on the polymerization rate, molecular weight, and molecular weight distribution of the polypropylene.1. Yield: Higher catalyst concentration generally leads to a higher yield of polypropylene. This is because the catalyst promotes the polymerization reaction, and more catalyst molecules mean more active sites for the reaction to occur. However, there is an optimal concentration beyond which the yield may not increase significantly, as the reaction may become diffusion-limited or the catalyst may deactivate due to side reactions.2. Molecular weight: The molecular weight of the polypropylene is influenced by the catalyst concentration. Higher catalyst concentration can lead to a lower molecular weight, as there are more active sites for the polymerization reaction, resulting in shorter polymer chains. Conversely, lower catalyst concentration can result in higher molecular weight, as there are fewer active sites, leading to longer polymer chains.3. Molecular weight distribution: The molecular weight distribution of the polypropylene is also affected by the catalyst concentration. Higher catalyst concentration can lead to a broader molecular weight distribution, as there are more active sites for the polymerization reaction, resulting in a wider range of polymer chain lengths. A narrower molecular weight distribution can be achieved with lower catalyst concentrations.In summary, the concentration of the Ziegler-Natta catalyst plays a crucial role in determining the yield and properties of the resultant polypropylene. It is essential to optimize the catalyst concentration to achieve the desired polymer properties for specific applications.