Competitive chain transfer by [beta]-hydrogen and [beta]-methyl elimination for the model Ziegler-Natta olefin polymerization system [Me[sub 2]Si([eta][sup 5]-C[sub 5]Me[sub 4])[sub 2]]Sc(CH[sub 2]CH(CH[sub 3])[sub 2])(PMe[sub 3])
- California Inst. of Technology, Pasadena, CA (United States)
The reaction of OpSc(H)(PMe[sub 3]) (Op = (([eta][sup 5]-C[sub 6]Me[sub 4])[sub 2]SiMe[sub 2])) with isobutene produces OpSc(CH[sub 3])(PMe[sub 3]) along with isobutene, 2-methylpentane, isobutene, 2-methyl-1-pentene, propane, and n-pentane. These products arise from a series of reactions involving olefin insertion, [beta]-CH[sub 3] and (faster) [beta]-H elimination which proceed until only the 2-methyl-1-alkenes (C[sub 4]H[sub 8], C[sub 6]H[sub 12], etc.) and the predominant organoscandium product OpSc(CH[sub 3])(PMe[sub 3]) remain. A transient observed in the reaction sequence has been unambiguously characterized as OpSc(CH[sub 2]CH[sub 2]CH[sub 3])(PMe[sub a]). Slower [sigma] bond metathesis involving the methyl C-H bonds of PMe[sub 3] and the Sc-C bonds of the scandium alkyls accounts for the observation of saturated alkanes 2-methylalkanes (C[sub 4]H[sub 10], C[sub 6]H[sub 14], etc.), normal alkanes (C[sub 3]H[sub 8],C[sub 5]H[sub 12], etc.), and a minor organoscandium product OpScCh[sub 2]Pme[sub 2] in the product mixture. [beta]-Ethylmigration is not observed for the closely related 2-ethylbutyl derivative, OpSc(CH[sub 2]CH(C[sub 2]H[sub 5])CH[sub 2]CH[sub 3])(PMe[sub 3]), obtained from reaction of 2-ethyl-1-butene with OpSc(H)(PMe[sub 3]). 28 refs., 2 figs., 1 tab.
- OSTI ID:
- 7267481
- Journal Information:
- Organometallics; (United States), Vol. 13:4; ISSN 0276-7333
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
36 MATERIALS SCIENCE
2-METHYLPROPENE
CHEMICAL REACTIONS
ALKENES
POLYMERIZATION
SCANDIUM COMPLEXES
2-METHYLPROPANE
ALKYL RADICALS
CHEMICAL BONDS
CHEMICAL REACTION KINETICS
DEHYDROGENATION
ORGANOMETALLIC COMPOUNDS
PENTANE
PROPANE
ZIEGLER CATALYST
ALKANES
CATALYSTS
COMPLEXES
HYDROCARBONS
KINETICS
ORGANIC COMPOUNDS
RADICALS
REACTION KINETICS
TRANSITION ELEMENT COMPLEXES
400201* - Chemical & Physicochemical Properties
360601 - Other Materials- Preparation & Manufacture