منابع مشابه
Ziegler-Natta Catalysis: Structural Variations and Tacticity Control
Models for the likely active catalysts in homogeneous Ziegler-Natta systems have been studied using ab initio quantum chemical methods. We investigated the geometries of the isoelectronic model complexes, X2M-R where X = C1 or Cp = (q5-CsHs); where M = Sc and Ti+ (and also Ti); and where R = H, CH3, or SiH3. The general trend is that the M = Sc compounds strongly prefer a planar configuration, ...
متن کاملFirst Principles Molecular Dynamics Study of Catalysis for Polyolefins: the Ziegler-Natta Heterogeneous System
We review part of our recent ab initio molecular dynamics study on the Ti-based Ziegler-Natta supported heterogeneous catalysis of α-olefins. The results for the insertion of ethylene in the metal-carbon bond are discussed as a fundamental textbook example of polymerization processes. Comparison with the few experimental data available has shown that simulation can reproduce activation barriers...
متن کاملTheoretical study on a reaction pathway of Ziegler - Natta - type catalysis a )
Ab initio SCF-LCAO-MO all-electron calculations have been performed for the catalyzed reaction, related to the Ziegler-Natta polymerization process TiCl.·Al(CH3)3+C2H. -+TiCl •. Al(CH3h·C3H7. The energy of the Ti-Al--ethylene complex during the reaction pathway is associated to the following processes: First, the ethylene coordinates to the catalyst complex and subsequently it reacts with the m...
متن کاملOrganometallic Group 4 Bis ( Borylamide ) Complexes as Templates for Ziegler - Natta Catalysis
Chapter 1 Motivated by the isolobal and isoelectronic relationship between the do CpW(CR) fragment and the do bent metallocene core, the synthesis and reactivity of alkyl complexes of the type CpW(CAd)R 2 (Ad = 1-adamantyl; R = alkyl, Cl, NMe 2 ) are presented. AdCN reacts with W2 (OCMe3 )6 to provide W(CAd)(OCMe 3)3, from which CpW(CAd)C12 may be prepared in three steps. Alkylation of CpW(CAd)...
متن کاملHistorical and Philosophical Remarks on Ziegler-Natta Catalysts: A Discourse on In-dustrial Catalysis
Part 1 outlines the complex, parallel historical evolution of ZieglerNatta catalysts and related problems. In Part 2, as a general method of inquiry, chemical language and discourse are analyzed, at first to clarify chemists’ epistemic views and the ontological status of catalysts. After analyzing contrasting definitions of ‘catalyst’ and the chemical properties of catalysts, a suitable metapho...
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ژورنال
عنوان ژورنال: MRS Bulletin
سال: 2013
ISSN: 0883-7694,1938-1425
DOI: 10.1557/mrs.2013.50