Multicyclic metallocycle metallocenes and their use

A process for producing a new metallocene comprising reacting a first metallocene which has a cyclodiene group having an olefinically unsaturated substituent with about two molar equivalents of an alkali metal alkyl, catalyst systems resulting from the combination of the resulting metallocene and an organoaluminum cocatalysts, and polymerization processes using such catalyst systems are disclosed.

EXAMPLE 1 A metallocene was prepared by reacting 1-(9-fluorenyl)-1-(3-butenylcyclopentadienyl)-1,1-dimethyl methane zirconium dichloride with two molar equivalents of n-butyl lithium in toluene at −78° C. The reaction product was filtered and the solvent was removed from the filtrate and the solvent was removed to recover the metallocene. The NMR of the resulting metallocene was consistent with a metallocene of the above general formula wherein n is 2, L is cyclopentadienyl, L′ is 9-fluorenyl, M is Zr, andY is dimethyl methylene. The resulting metallocene was combined with a toluene solution of methyl aluminoxane and used to evaluate the effectiveness of the metallocene in the polymerization of ethylene. The aluminoxane was used in such an amount that the Al/Zr molar ratio was 3000:1. The polymerization was conducted in pentane for 1 hour at 60° C. and an ethylene pressure of 10 bar. The polyethylene recovered demonstrated that the catalyst system had an activity of 41,600 grams of polyethylene per gram of Zr per hour. In addition it was noted that there was only minor fouling observed, which lead to the conclusion that the novel metallocene self immobilized to form a catalyst system that was insoluble in the polymerization medium. Accordingly, the metallocene is a good canditate for preparing solid particulate prepolymerized catalyst systems that would be useful in commercial slurry polymerization processes. Another of polymerization was conducted in the same manner except for replacing the inventive metallocene with the metallocene 1-(9-fluorenyl)-1-(3-butenylcyclopentadienyl)-1,1-dimethyl methane zirconium dichloride. In that case the catalyst system was slightly more active, i.e. 58,700 grams of polyethylene per gram of Zr per hour but there were significant amounts of fouling.