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Abstract The homogeneous Ziegler‐Natta–catalysts, consisting of a zirconocene compound and methyl‐aluminoxane, lead to extremely high polymerization activities. With bis(cyclopentadienyl)zirconium dichloride pure atactic polypropylene and polyethylene with activities up to 30.10 6 g PE/g Zr·h are formed. The higher the degree of oligomerization of the aluminoxane the more active are the catalysts. The density of polyethylene (LLDPE) can be lowered by using 1‐butene or 1‐hexene as comonomers. Incorporation of dienes gives EPDM‐elastomers. Highly isotactic polypropylene can be prepared by using chiral rac‐ethylene bis–(tetrahydroindenyl) zirconium dichloride together with methylaluminoxane as cocatalyst. The toluene soluble part here consists of less than 0.2 weight percent. After resolution of this racemate it is also possible to produce optically active polypropylene and polybutene.
Kaminsky et al. (Sun,) studied this question.