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])

Journal Article · Fri Apr 01 04:00:00 EST 1994 · Organometallics; (United States)

DOI:https://doi.org/10.1021/om00016a018· OSTI ID:7267481

Hajela, S; Bercaw, J E ^[1]

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1. 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), Journal Name: Organometallics; (United States) Vol. 13:4; ISSN ORGND7; ISSN 0276-7333
• Country of Publication: United States
• Language: English

Related Subjects

2-METHYLPROPANE
2-METHYLPROPENE
36 MATERIALS SCIENCE
360601 -- Other Materials-- Preparation & Manufacture
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ALKANES
ALKENES
ALKYL RADICALS
CATALYSTS
CHEMICAL BONDS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COMPLEXES
DEHYDROGENATION
HYDROCARBONS
KINETICS
ORGANIC COMPOUNDS
ORGANOMETALLIC COMPOUNDS
PENTANE
POLYMERIZATION
PROPANE
RADICALS
REACTION KINETICS
SCANDIUM COMPLEXES
TRANSITION ELEMENT COMPLEXES
ZIEGLER CATALYST