Ziegler-Natta polymerization of {alpha}-olefins with organoyttrium compounds

Conference · Fri Dec 31 04:00:00 EST 1993

OSTI ID:141046

Coughlin, E B; Bercaw, J E ^[1]

---

1. 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--
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
40 CHEMISTRY
ALKENES
CATALYTIC EFFECTS
CRYSTAL STRUCTURE
ORGANOMETALLIC COMPOUNDS
POLYMERIZATION
YTTRIUM COMPOUNDS