Ziegler polymerization of 4‐methyl‐1‐pentene

Polymerization of 4‐methyl‐1‐pentene was carried out at 40°C. in n‐heptane with the use of catalysts prepared from TiCl4 and triethylaluminum or triisobutylaluminum. Yield of polymer at the end of a fixed time (4 hr.) was used as a measure of catalyst activity. Solubility of the polymer in boiling heptane was used as a measure of stereospecificity. Both activity and stereospecificity are strongly affected by the ratio of aluminum alkyl to titanium tetrachloride in the catalyst. Yield was greatest for catalysts in which Al/Ti was between 1.2 and 2.0. Highest percentage of heptane‐insoluble polymer was obtained at Al/Ti equals; 1. Stereospecificity was little affected by the monomer/catalyst ratio in the ranges studied. Catalysts prepared from triethylaluminum gave slightly higher percentages of heptane‐insoluble polymer than did triisobutylaluminum.