Download or read book Octahedral Bis phenolate Ether Group IV Metal Complexes for Polymerization and Copolymerization of Alpha olefins written by Elizabeth Tanzini Kiesewetter and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Octahedral group IV bis(phenolate) ether complexes, activated by methylaluminoxane, are highly active and stereospecific [alpha]-olefin polymerization catalysts. X-ray crystallographic analysis reveals the Zr and Hf complexes to be closely isostructural; the bond lengths of the Hf complex are slightly shorter, but the maximum deviation is only 0.062 Å. Despite the structural similarity of the Hf and Zr complexes, the Hf complexes generate more highly stereoselective catalysts. In addition to the influence of the transition metal, the structure of the ligand has a large influence on the stereospecificity. Bis-t-Butyl phenyl substituted complexes of Hf and Zr, when activated by MAO at 50 - 80 °C, generate high molecular weight polypropylene (Mn = 130,000 - 360,000 g/mol) with isotacticities [mmmm]> 0.97 and melting points as high as 165°C. Octahedral group IV bisphenolate ether complexes, activated by methylaluminoxane, were also tested in propylene polymerization in the presence diethyl zinc. Although the Hf and Zr complexes are structurally similar, propylene polymerization behavior of the two catalysts differs significantly in terms of productivity, isospecificity and propensity to incorporate specific regioerrors. 13C-NMR analysis revealed that the type and the number of regioerrors being incorporated into the polymer chain are strongly dependent on the identity of the ligand and the metal. Low molecular weight polypropylene oligomers (Mn = 1700 - 9900 g/mol), generated in the presence of diethyl zinc facilitated end group analysis, which revealed the presence of isobutyl and 2-methylbutyl groups. Octahedral bis(phenolate) catalysts are highly active catalysts for the isospecific polymerization of 1-hexene and the production of high molecular weight ethylene/1-hexene copolymers. These catalysts are active for the production of high molecular weight copolymers even at high temperatures. The reactivity ratios for these complexes were determined; all of the bis(phenolate) complexes tested showed reasonable 1-hexene incorporations. The complexes prepared from the more sterically demanding ligands showed higher incorporations of comonomers than those prepared from the less sterically demanding ligands. Complexes of the type Cp*TiX2(ONR'R'') (Cp* = [Eta]5-C5Me5, X = Me, Cl; R = Et, TEMPO (2,2,6,6-tetramethylpiperidine-N-oxyl); X = R' = Me, R'' = tBu) were synthesized by several routes. Upon activation with [Ph3C]+[B(C6F5)4]- and AliBu3, these complexes generate highly active catalysts for propylene polymerization, although significant catalyst deactivation was observed. Activation with B(C6F5)3/AliBu3 or methylaluminoxane (MAO) resulted in reduced polymerization activity; the latter leading to increased catalyst lifetime. Reaction of Cp*Ti(Me)2(ONEt2) and Cp*Ti(Me)2(ONtBu(Me)) with B(C6F5)3 resulted in clean formation of the zwitterionic contact ion pairs, [Cp*Ti(Me)([Eta]2-ONEt2)]+[MeB(C6F5)3]- and [Cp*Ti(Me)([Eta]2-ONtBu(Me))]+[MeB(C6F5)3]- respectively whereas reaction of Cp*Ti(Me)2([Eta]2-ONtBu(Me)) with [Ph3C]+[B(C6F5)4]- resulted in the clean formation of the solvent-separated ion pair [Cp*Ti(Me)([Eta]2-ONtBu(Me))]+[B(C6F5)4]-. Addition of AliBu3 or AlMe3 to the cationic [Cp*Ti(Me)(ONtBu(Me))]+[B(C6F5)4]- resulted in decomposition of the cations.
Download or read book Synthesis of Group 4 Metal Octahedral Bis phenolate Complexes for Propylene Polymerization written by Madalyn Radlauer and published by . This book was released on 2008 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Transition Metals and Organometallics as Catalysts for Olefin Polymerization written by Walter Kaminsky and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 443 pages. Available in PDF, EPUB and Kindle. Book excerpt: More than 30 years after the discovery of transition metals and organometal lics as catalysts for olefin polymerization these catalysts did not have lost their fascination. Since 1953 when Karl Ziegler has discovered the catalytic polymerization of ethylene leading to plastically formable polymers which are mechanically stable up to temperatures of about 100°C, synthetic polymers and rubbers have made their way right into private houses. This discovery has been a main impetus for the fast growing production of plastics. The stereoselective poly merization of propylene and other long-chain a-olefins first detected by Giulio Natta leads to an even broadened field of applications. Another enforcing factor were the developments of Standard Oil of Indiana and Phillipps Petroleum Company who engaged in the polymerization of a-olefins supported molybdenum, cobalt and later on chromium catalysts which clearly indicates the wide variety of suitable systems. This kind of research acknowledged merit when in 1963 the Nobel prize of chemistry was awarded to Ziegler and Natta. Although to a great extent there is a technical application for these catalysts, up to now the nature of the active centres and many reaction mechanisms are not completely known.
Download or read book Group 4 Metal Octahedral Complexes as Catalysts for Olefin Polymerization written by Marina Lamberti and published by . This book was released on 2003 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book New Group Four Organometallic Complexes and Their Use as Homogeneous alpha olefin Polymerization Catalysts written by Patrick Foster and published by . This book was released on 1997 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Olefin Polymerization written by Walter Kaminsky and published by Wiley-VCH. This book was released on 2006-08-18 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: With an enormous velocity, olefin polymerization has expanded to one of the most significant fields in polymers since the first industrial use about 50 years ago. In 2005, 100 million tons of polyolefins were produced - the biggest part was catalyzed by metallorganic compounds. The Hamburg Macromolecular Symposium 2005 with the title "Olefin Polymerization" involved topics such as new catalysts and cocatalysts, kinetics, mechanism and polymer reaction engineering, synthesis of special polymers, and characterization of polyolefins. The conference combined scientists from different disciplines to discuss latest research results of polymers and to offer each other the possibility of cooperation. This is reflected in this volume, which contains invited lectures and selected posters presented at the symposium.
Download or read book Novel Group Four Complexes for the Polymerization and Copolymerization of Olefins written by Matthew N. Herzog and published by . This book was released on 2003 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Iron Catalysis written by Bernd Plietker and published by Springer Science & Business Media. This book was released on 2011-01-05 with total page 227 pages. Available in PDF, EPUB and Kindle. Book excerpt: Juan I. Padrón and Víctor S. Martín: Catalysis by means of Fe-based Lewis acids; Hiroshi Nakazawa*, Masumi Itazaki: Fe–H Complexes in Catalysis; Kristin Schröder, Kathrin Junge, Bianca Bitterlich, and Matthias Beller: Fe-catalyzed Oxidation Reactions of Olefins, Alkanes and Alcohols: Involvement of Oxo- and Peroxo Complexes; Chi-Ming Che, Cong-Ying Zhou, Ella Lai-Ming Wong: Catalysis by Fe=X Complexes (X=NR, CR2); René Peters, Daniel F. Fischer and Sascha Jautze: Ferrocene and Half Sandwich Complexes as Catalysts with Iron Participation; Markus Jegelka, Bernd Plietker: Catalysis by Means of Complex Ferrates.
Download or read book Iron Catalysis in Organic Chemistry written by Bernd Plietker and published by John Wiley & Sons. This book was released on 2008-09-08 with total page 295 pages. Available in PDF, EPUB and Kindle. Book excerpt: This first comprehensive book to cover this exciting field also deals with the biological aspects, such as enzymes with iron. Following an introduction, this handy reference and handbook goes on to deal with reductions, oxidations of C, H- and C=C bonds, oxidative allylic oxygenation and amination, the oxidation of heteroatoms, cross coupling reactions, aromatic and nucleophilic substitutions, addition to carbonyl compounds, and cyclisations as well as ring opening reactions. The chapters are clearly classified according to the reaction type, allowing readers to quickly locate the desired information.
Download or read book Late Transition Metal Polymerization Catalysis written by Bernhard Rieger and published by John Wiley & Sons. This book was released on 2006-03-06 with total page 345 pages. Available in PDF, EPUB and Kindle. Book excerpt: At the start of the 1950s, Ziegler and Natta discovered that simple metallorganic catalysts are capable of transforming olefins into linear polymers with highly ordered structures. This pioneering discovery was recognized with a Nobel Prize in 1963. In the 80s and 90s, the development of molecular defined metallocenes led to a renaissance for non-polar polyolefin materials. Designer catalysts allowed a greater precision in defining properties of the material. The past 10 years have seen the discovery of new catalysts based on late transition metals, which allow the combination of polar monomers with non-polar olefins and thus lead to innovative materials. Here, the world's leading authors from industry and academia describe the latest developments in this fascinating field for the first time in such comprehensive detail. In so doing, they introduce readers systematically to the basic principles and show how these new catalysts can effectively be used for polymerization reactions. This makes the book an ideal and indispensable reference for specialists, advanced students, and scientists of various disciplines dealing with research into catalysts and materials science.
Download or read book Introduction to Industrial Polypropylene written by Dennis B. Malpass and published by John Wiley & Sons. This book was released on 2012-07-02 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt: This introductory text is an important resource for new engineers, chemists, students, and chemical industry personnel to understand the technical aspects of polypropylene which is the 2nd largest synthetics polymer in manufactured output. The book considers the following topics: What are the principal types of polypropylene and how do they differ? What catalysts are used to produce polypropylene and how do they function? What is the role of cocatalysts and how have they evolved over the years? How are industrial polypropylene catalysts tested and the resultant polymer evaluated? What processes are used in the manufacture of polypropylene? What are the biopolymer alternatives to polypropylene? What companies are the major industrial manufacturers of polypropylene? What is the environmental fate of polypropylene?
Download or read book Metathesis Polymerization of Olefins and Polymerization of Alkynes written by Yavuz İmamoğlu and published by Springer Science & Business Media. This book was released on 1998 with total page 468 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains contributions from inorganic, organic and polymer chemists, who join forces to report on the state of the art in ring opening metathesis polymerization, acyclic diene metathesis and alkyne polymerization. Topics covered are: mechanism of ROMP reactions, new catalysts for ROMP, new products by ROMP, new catalysts for ADMET, new products by ADMET, degradation of polymers by metathesis reactions, alkyne polymerization and metathesis, and industrial applications of metathesis reactions.
Download or read book Zinc Catalysis written by Stephan Enthaler and published by John Wiley & Sons. This book was released on 2015-04-27 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt: Filling the gap in the market for comprehensive coverage of this hot topic, this timely book covers a wide range of organic transformations, e. g. reductions of unsaturated compounds, oxidation reactions, Friedel-Crafts reactions, hydroamination reactions, depolymerizations, transformations of carbon dioxide, oxidative coupling reactions, as well as C-C, C-N, and C-O bond formation reactions. A chapter on the application of zinc catalysts in total synthesis is also included. With its aim of stimulating further research and discussion in the field, this is a valuable reference for professionals in academia and industry wishing to learn about the latest developments.
Download or read book Catalytic Olefin Polymerization written by T. Keii and published by Elsevier. This book was released on 1990-09-12 with total page 597 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent development of a new generation of Ziegler-Natta Catalysts using either magnesium dichloride as carrier or methylaluminoxane as cocatalyst has markedly stimulated the research activity in the field of olefin polymerization. These discoveries have not only yielded economical processes for polyolefin production but also opened the way to a new generation of novel polymers. Moreover, the nature of active species is being clarified well by the effort to simplify catalyst systems. The present volume includes 38 papers from the 31 lectures and 18 posters presented at the symposium on `Recent Developments in Olefin Polymerization Catalysts', which covered the following topics: Overview of super-active homogeneous and heterogeneous catalysts, kinetic profile of olefin polymerization including copolymerization, characterization of catalysts and polymers, methods for the determination of active center concentration, role of Lewis bases on the catalysts isospecificity, polymerization mechanisms, and synthetic pathways for functionalized polyolefins. The contents are well balanced between fundamental research and application as well as between homogeneous and heterogeneous catalyst systems.
Download or read book Macromolecular Metal Carboxylates and Their Nanocomposites written by Anatolii D. Pomogailo and published by Springer Science & Business Media. This book was released on 2010-09-02 with total page 311 pages. Available in PDF, EPUB and Kindle. Book excerpt: Data on the synthesis and physicochemical studies of salts of mono- or dibasic unsaturated carboxylic acids and macromolecular metal carboxylates are generalised and described systematically in this monograph. The structures and properties of the COO group in various compounds and characteristic features of the structures of carboxylate are analysed. The main routes and kinetics of polymerisation transformations of unsaturated metal carboxylates are considered. The attention is focused on the effect of the metal ion on the monomer reactivity and the polymer morphology and structure. The possibility of stereochemical control of radical polymerisation of unsaturated metal carboxylates is demonstrated. The electronic, magnetic, optical, absorption and thermal properties of metal (co)polymers and nanocomposites and their main applications are also considered.
Download or read book Surface Organometallic Chemistry Molecular Approaches to Surface Catalysis written by Jean-Marie Basset and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surface organometallic chemistry is a new field bringing together researchers from organometallic, inorganic, and surface chemistry and catalysis. Topics ranging from reaction mechanisms to catalyst preparation are considered from a molecular basis, according to which the "active site" on a catalyst surface has a supra-molecular character. This. the first book on the subject, is the outcome of a NATO Workshop held in Le Rouret. France, in May. 1986. It is our hope that the following chapters and the concluding summary of recommendations for research may help to provide a definition of surface organometallic chemistry. Besides catalysis. the central theme of the Workshop, four main topics are considered: 1) Reactions of organometallics with surfaces of metal oxides, metals. and zeolites; 2) Molecular models of surfaces, metal oxides, and metals; 3) Molecular approaches to the mechanisms of surface reactions; 4) Synthesis and modification of zeolites and related microporous solids. Most surface organometallic chemistry has been carried out on amorphous high-surf ace-area metal oxides such as silica. alumina. magnesia, and titania. The first chapter. contributed by KNOZINGER. gives a short summary of the structure and reactivity of metal oxide surfaces. Most of our understanding of these surfaces is based on acid base and redox chemistry; this chemistry has developed from X-ray and spectroscopic data, and much has been inferred from the structures and reactivities of adsorbed organic probe molecules. There are major opportunities for extending this understanding by use of well-defined (single crystal) oxide surfaces and organometallic probe molecules.
Download or read book Metal Organic Frameworks written by Leonard R. MacGillivray and published by John Wiley & Sons. This book was released on 2010-12-17 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt: Metal-organic frameworks represent a new class of materials that may solve the hydrogen storage problem associated with hydrogen-fueled vehicles. In this first definitive guide to metal-organic framework chemistry, author L. MacGillivray addresses state-of-art developments in this promising technology for alternative fuels. Providing professors, graduate and undergraduate students, structural chemists, physical chemists, and chemical engineers with a historical perspective, as well as the most up-to-date developments by leading experts, Metal-Organic Frameworks examines structure, symmetry, supramolecular chemistry, surface engineering, metal-organometallic frameworks, properties, and reactions.
