The most effective catalyst for the synthesis of polypropylene from propylene monomer is the Ziegler-Natta catalyst. This catalyst is a combination of a transition metal compound usually titanium-based, such as titanium trichloride, TiCl3 and an organometallic compound usually an aluminum alkyl, such as triethylaluminum, Al C2H5 3 .Optimal reaction conditions for the synthesis of polypropylene using the Ziegler-Natta catalyst are as follows:1. Temperature: The reaction is typically carried out at a temperature range of 60-80C 140-176F . Higher temperatures can lead to faster reaction rates, but may also result in the formation of undesirable by-products.2. Pressure: The polymerization reaction is usually performed under moderate pressure, typically in the range of 1-10 atmospheres. Higher pressures can lead to increased molecular weight of the polymer, but may also result in increased reactor costs and safety concerns.3. Solvent: The reaction is often carried out in an inert solvent, such as hexane or heptane, to help control the reaction rate and improve heat transfer. The solvent should be free of impurities that could interfere with the catalyst or the polymerization process.4. Catalyst concentration: The concentration of the Ziegler-Natta catalyst should be optimized to achieve the desired polymer properties, such as molecular weight and polydispersity. Typically, a catalyst concentration of 0.1-1.0 mol% based on the monomer is used.5. Reaction time: The polymerization reaction is usually carried out for several hours to achieve a high conversion of the propylene monomer to polypropylene. The reaction time can be adjusted to control the molecular weight and other properties of the polymer.6. Inert atmosphere: The polymerization reaction should be carried out under an inert atmosphere such as nitrogen or argon to prevent the oxidation of the catalyst and the formation of undesirable by-products.By optimizing these reaction conditions, it is possible to achieve high yields and desired properties of polypropylene from the propylene monomer using the Ziegler-Natta catalyst.