Results 181 to 190 of about 1,886 (220)

Metallocene Catalysts for Olefin Oligomerization

Macromolecular Symposia, 2006
AbstractMetallocene complexes with a cocatalyst such as methylalumoxane, MAO can be used as catalysts in the dimerization or oligomerization of olefins (alkenes) including the (co‐/hydro‐)oligomerization of ethene, of the α‐olefins propene, 1‐butene, 1‐pentene, 1‐hexene, and higher α‐olefins, branched α‐olefins, cyclic olefins and α,ω‐dienes.
Janiak, Christoph, Blank, Jan-Frederik
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Olefin copolymerization with metallocene catalysts. III. Supported metallocene/methylaluminoxane catalyst for olefin copolymerization

Journal of Polymer Science Part A: Polymer Chemistry, 1991
AbstractSupported catalyst for fluidized bed polymerization processes has been prepared by reacting macroporous SiO2 first with MAO (methylaluminoxane) and then with Et [Ind]2ZrCl2. It contains 0.60 wt % of Zr and an [Al]/[Zr] ratio of 50. This catalyst produces homogeneous E/P (ethylene/propylene) copolymers with truly random copolymerization ...
James C. W. Chien, Dawei He
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Alternating Ethene/Propene Copolymerization with a Metallocene Catalyst

Angewandte Chemie International Edition, 1998
A small variation in the substituent R' on the metallocene catalyst employed in the copolymerization of ethene and propene leads to a highly alternating (81-83%) structure (1) rather than a statistical copolymer. Such copolymers were until recently only accessible by hydrogenation of polyisoprene or 1,4-poly(pentadiene).
Margarete K, Leclerc, Robert M, Waymouth
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Olefin Polymerization with Metallocene Catalysts

2014
This chapter firstly explains the basic terms and concepts concerning olefin polymerization and polymer synthesis, and then provides comprehensive yet concise commentaries on olefin polymerization by metallocene catalysts. In Sect. 1.1 (Introduction), the history of olefin polymerization catalysts is briefly reviewed with a focus on the uniformity of ...
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New polyolefins by metallocene catalysts

Pure and Applied Chemistry, 1998
Abstract
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New application for metallocene catalysts in olefin polymerization

Dalton Transactions, 2009
Metallocenes and other transition metal complexes, activated by methylaluminoxane allow the synthesis of polyolefins with a highly defined microstructure, tacticity, and stereoregularity. New copolymers, long chain branched polymers, and polyolefin nanocomposites are produced by these highly active catalysts.
Walter, Kaminsky, Andreas, Funck, Heinrich, Hähnsen   +2 more
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A Metallocene-Pyrrolidinopyridine Nucleophilic Catalyst for Asymmetric Synthesis

Organic Letters, 2006
[reaction: see text] A highly active chiral 4-aminopyridine nucleophilic catalyst, available in three steps from (S,S)-hexane-2,5-diol, was applied to the asymmetric Steglich rearrangement of O-aceylated azlactones (1 mol % loading, up to 76% ee).
Huy V, Nguyen, David C D, Butler, Christopher J, Richards   +2 more
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Metallocene Catalysts in Dispersed Media

1997
Metallocene catalysts are organometallic coordination compounds in which one or two cyclopentadienyl rings or substituted cyclopentadienyl rings are bonded to a central transition metal atom, as shown in Figure1. The nature and number of the rings and substituents (S), the type of transition metal (M) and its substituents (R), the type of the bridge ...
J. B. P. Soares, A. E. Hamielec
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Copolymerization of ethylene and ?-olefins with combined metallocene catalysts. II. Mathematical modeling of polymerization with single metallocene catalysts

Journal of Polymer Science Part A: Polymer Chemistry, 2000
The relation between the polymerization conditions and the distributions of molecular weight (MWD) and chemical composition (CCD) of poly(ethylene-co-1-hexene) made with single supported metallocene catalysts was investigated. Understanding the behavior of each metallocene under different polymerization conditions is necessary for designing combined ...
Jung Dae Kim, João B. P. Soares
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Metallocene catalysts technology and environment

Comptes Rendus de l'Académie des Sciences - Series IIC - Chemistry, 2000
Abstract The polyolefin industry is increasingly confronted with the challenge to meet restricting environmental regulations. In parallel, the environmentally conscious public opinion (customer!), now globally organized, demands even more stringent anticipative actions to prevent any short or long term damages inflicted upon environment.
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