Ziegler-Natta polymerization of {alpha}-olefins with organoyttrium compounds
- California Institute of Technology, Pasadena, CA (United States)
The single component iso-specific olefin polymerization catalyst [rac-Me{sub 2}Si(2-SiMe{sub 3}-4-CMe{sub 3}-C{sub 5}H{sub 2})Y-H]{sub 2}, [rac-BpY-H]{sub 2}, has recently been described. {sup 13}C NMR spectra of the resulting polymers show a high degree of isotacticity for all polymer samples, >97% mmmm for polypropylene. A preliminary X-ray crystal structure determination of the bridging hydride dimer, [rac-BpY-H]{sup 2}, has shown it to be homochiral (RR and SS enantiomers) as expected based upon steric considerations. Improved polymerization rates can be acheived by the hydrogenolysis of rac-BpY-CH(SiMe{sub 3}){sub 2}, in the presence of an {alpha}-olefin, without adversely effecting the polymer isotactivity. The alkyl, rac-BpY-CH(SiMe{sub 3}){sub 2}, is also an excellent catalyst for the copolymerization of ethylene and 1-butene. The synthesis and polymerization activity of various rac-BpY-R catalysts will be presented, as well as efforts designed towards probing the factors responsible for the resulting high isotacticities.
- OSTI ID:
- 141046
- Report Number(s):
- CONF-930304-; TRN: 93:003688-0719
- Resource Relation:
- Conference: 205. American Chemical Society national meeting, Denver, CO (United States), 28 Mar - 2 Apr 1993; Other Information: PBD: 1993; Related Information: Is Part Of 205th ACS national meeting; PB: 1951 p.
- Country of Publication:
- United States
- Language:
- English
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