Synthetic and Mechanistic Investigations of Polymerization Catalyzed for Early Transition Metal Compounds
The objectives of the research program are (1) to discover new types of chemical transformations between hydrocarbons and transition-metal compounds, (2) to investigate their mechanisms; and (3) to explore the possibilities of coupling these transformations with others to catalyze chemical reactions for the preparation of fuels, commodity chemicals and polymeric materials. A current focus is the catalytic polymerization of alpha-olefins. New and superior polymers with different microstructures and potentially very useful kinetic resolutions of abundant, racemic alpha-olefins could be realized, if sufficient control over the polymerization process could be achieved. Well defined, yttrocene catalysts have been synthesized, some with known absolute configurations, and their reactions with an isotopically chiral 1-pentene monomer have been examined. These experiments have revealed the absolute olefin facial preferences for 1-pentene addition to Y-H and Y-pentyl bonds. A new class of zirconocene catalysts having doubly-linked cyclopentadienyl ligands has been developed, which allow the preparation of polypropylenes varying from isotactic to syndiotactic. These catalysts are highly reactive, permitting the polymerization of normally unreactive monomers such as 3-substituted alpha olefins. Chiral versions effect polymerization of such racemic monomers with useful kinetic resolutions.
- Research Organization:
- California Institute of Technology (CalTech), Pasadena, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC); Office of Basic Energy Sciences
- DOE Contract Number:
- FG03-85ER13431
- OSTI ID:
- 775927
- Report Number(s):
- DOE/ER/13431-1-Pt.1; A018; TRN: US201208%%837
- Country of Publication:
- United States
- Language:
- English
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03 NATURAL GAS
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KINETICS
MONOMERS
POLYMERIZATION
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RESEARCH PROGRAMS
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