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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 24 for “"Olefin polymerization"”.
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Novel Group 4 Metal Amido Complexes - syntheses, reactivity and olefin polymerization catalysis
… found moderatly active for ethylene and styrene polymerization when activated with d-MAO giving syndiotactic polystyrene of high molecular weight and aluminum terminated polyethylene. The low activity of these complexes was attributed to the ligand transfer to aluminum during catalysis. Mono Ap …
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Group 10 Metal Catalytic Olefin Polymerization and Synthesis of Ethylene/Acrylate Block Copolymers
The functionalized polyolefin materials are considered economical and high performance materials used in a wide range of applications, such as upcycling polymers, elastomers, membranes, and compatibilizers. This dissertation focuses on developing group 10 metal catalysts for olefin polymerization …
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The synthesis, characterization and activation of some multinuclear catalyst precursors for olefin polymerization
… into the immobilization of homogeneous olefin polymerisation cataiysts on dendritic supports...; The dendrimers . employed were essentially allylaryl-ether type systems and consisted of both dendritic wedges .and compltte dendrimers.. These materials were used as supports for homogeneous …
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Living α-olefin polymerization by cationic zirconium and hafnium complexes containing chelating diamidopyridine ligands
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2002.
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The Use of Functionalized Zirconocenes as Precursors to Silica-Supported Zirconocene Olefin Polymerization Catalysts
… as precursors to silica-supported metallocene olefin polymerization catalysts. Our first objective was to extend the metallocene "functionalization" chemistry to obtain substituents bearing more than one electrophilic bond. The reactivities of Me3Sn and Ph2MeSi substituents were explored in …
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Quantitative Kinetic Analysis of Olefin Polymerization by Single-Site Group IV Amine Bis-Phenolate Catalysts
Polymerization by homogeneous single-site catalysts is a recent and growing area of research. While single-site catalysts are typically not as fast as heterogeneous ones, their major advantage is that the kinetic rate constants may be manipulated through precise changes to the catalyst structure …
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Polymerization and Isomerization of Olefins using Late-Transition Metal Complexes
… metal complexes serve as efficient olefin polymerization catalysts. The mechanism of α-diimine-palladium and nickel catalyzed olefin polymerization is well understood. By understanding the fundamental steps of olefin polymerization, catalysts can be rationally designed to achieve a …
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Observation of main chain chirality in isotactic polystyrene
… in terms of activity and selectivity in olefin polymerization.
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Studies of carbon-hydrogen and silicon-hydrogen bond activation by early transition metal complexes
… and chromium, are used as catalysts for olefin polymerization in the Ziegler-Natta and Phillips processes. The key intermediates in these catalysts are thought to be six-coordinate metal alkyl/olefin complexes. The synthesis and study of early transition metal alkyl complexes as models of …
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Kinetics and Mechanisms of Amine Bis-phenolate Polymerization Catalysts Featuring Titanium, Zirconium, or Hafnium Centers
<p>The story of Group IV metallocene polymerization catalysts has been a tremendous success in the ability to tune chemical reactivity through structural design. As new, nonmetallocene catalyst systems are being investigated, there has been a lack of quantitative relationships for predicting …
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Polymerization of olefins and functionalized monomers with zirconocene catalysts
… the application of zirconocene catalysis to the polymerization of nonfunctional 1-olefins and functional olefins, such as methacrylates. The polymerization of 1-hexene with zirconocene/MAO catalyst systems is studied in order to elucidate the nature of the active species on the basis of kinetic …
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Early transitional metal alkyl, alkylidene, and alkylidyne chemistry
… have been prepared and their proficiency in olefin polymerization reactions evaluated. The first set of supporting ligands examined are diamido-donor ligands that contain ethylene/o-phenylene "arms" and a phenyl-substituted amine donor in the central position. These ligands are derived from …
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Early transition metal catalysts for the living polymerization of olefins and alkynes
… ligand were prepared and employed in the polymerization of 1-hexene. Hafnium Ziegler-Natta catalysts containing the [(2,6- X2C6H3NHCH2)2C(CH3)(2-C5H4N)] ([Arx2NPy]2-) (X = Cl or F) ligand were also prepared for use in 1-hexene polymerization studies. Compounds of the type [Ligand]MR2 (R = …
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Self-Assembled Monolayers As Models For Silica
… as models for silica-immobilized metallocene olefin polymerization catalysts.
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Allylcalcium complexes : synthesis, reactivity and application in homogeneous catalysis
… A brief comparison of the activity in alpha-olefin polymerization is given. The parent compound bis(allyl)calcium is active in the polymerization of 1,3-butadiene but inactive in the polymerization of ethylene. Compounds bearing cationic [Ca(C3H5)]+ show no activity in the polymerization of …
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Computational Studies of Selected Ruthenium Catalysis Reactions.
… relevant to catalytic hydroarylation of olefins. These processes involved the +2 to +3 oxidation of ruthenium and its effect on ruthenium-carbon bond strengths, carbon-hydrogen bond activation by 1,2-addition/reductive elimination pathways appropriate to catalytic hydrogen/deuterium …
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Examination of Dynamic Processes in Living Ziegler-Natta Polymerization and New Polypropylene Architectures through Bimolecular Control
… to be a highly active initiator for living alpha-olefin polymerization. Discrete cationic CPZA alkyl complexes of the general structure {Cp*ZrR[N(Et)C(Me)N(tBu)]}[B(Csub6Fsub5)sub4] were studied as model complexes for living polymers derived from this system. Detailed analysis of models in which R …
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Probing Organometallic Reactions With 19F NMR
… (MAO) that lead to active Ziegler-Natta olefin polymerization catalysts. A novel experimental approach is described, in which a unique spectroscopic probe (a fluorinated substituent) is attached to the metallocene ancillary ligands and the metallocene/MAO mixtures are analyzed using 19F …
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