Hence, both unusually highly isotactic polypropylene as well as isotactic polybutene can be produced with 1 and methylalumoxane; the activity of the catalyst is high. The narrow molecular weight distribution, an additional effect, might be of interest from an industrial processing point of view.
Experimental
I : Tetrahydrofuran (THF) (60 mL) was distilled into a three-necked flask at -196°C and treated, with stirring, with 4.9 g (21 mmol) of ZrCI,. A solution of the dilithium salt of his(l-indeny1)ethane (21 mmol) in T H F (50 mL) was then added dropwise to the mixture under N:, at room temperature. After 2 hours' stirring, hydrogen chloride was passed into the mixture and, immediately thereafter, the excess HCI was removed in vacuo. The mixture was then treated with diethyl ether (20 inL) and petroleum ether (10 mL). The resulting light-yellow, crystalline product was filtered off and washed successively with 4 N hydrochloric acid, water, ethanol, and diethyl ether and dried in vacuo: yield 3.1 g of (R,S)-ethylenebis(1-indeny1)zirconium dichloride. I g of this substance was hydrogenated, as described for the analogous titanium compound [4], for 30 min with 75 mg Pt02 and 25 mL CH2CIZ at 100 bar H,; yield 650 mg of 1 (characterized by X-ray structure analysis 151).
Polymerization of propene: A solution of methylalumoxane (320 mg, 5.6 mmol Al) and 1 (3.3 x 10 -' mol) in I mL of toluene was added to 330 m L toluene contained in a 1 L glass autoclave fitted with a thermostat and magnetic stirrer and previously dried out and purged with argon. After 20 minutes' ageing, purified propene (70 mL) was distilled into the contents of the autoclave at 20°C. The solution gradually clouded, and white polypropylene precipitated out. After 120 min the contents of the autoclave were treated with ethanol, filtered, and the filter cake washed with dilute HCI and dried in vacuo; yield 31.3 g of isotactic polypropylene. On removal of toluene from the filtrate there remained a further 0.3 g of polypropylene.