Development of Late Transition Metal Catalysts for Olefin Polymerization - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Development of Late Transition Metal Catalysts for Olefin Polymerization write by Shingo Kikukawa. This book was released on 2000. Development of Late Transition Metal Catalysts for Olefin Polymerization available in PDF, EPUB and Kindle.
Metal Catalysts in Olefin Polymerization
Metal Catalysts in Olefin Polymerization - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Metal Catalysts in Olefin Polymerization write by Zhibin Guan. This book was released on 2009-03-31. Metal Catalysts in Olefin Polymerization available in PDF, EPUB and Kindle. Polyolefin is a major industry that is important for our economy and impacts every aspect of our lives. The discovery of new transition metal-based catalysts is one of the driving forces for the further advancement of this field. Whereas the classical heterogeneous Ziegler-Natta catalysts and homogeneous early transition metal metallocene catalysts remain the workhorses of the polyolefin industry, in roughly the last decade, tremendous progress has been made in developing non-metallocene-based olefin polymerization catalysts. Particularly, the discovery of late transition metal-based olefin polymerization catalysts heralds a new era for this field. These late transition metal complexes not only exhibit high activities rivaling their early metal counterparts, but more importantly they offer unique properties for polymer architectural control and copolymerization with polar olefins. In this book, the most recent major breakthroughs in the development of new olefin polymerization catalysts, including early metal metallocene and non-metallocene complexes and late transition metal complexes, are discussed by leading experts. The authors highlight the most important discoveries in catalysts and their applications in designing new polyolefin-based functional materials.
Development of Late Transition Metal Catalysts and Advanced Polyolefins
Development of Late Transition Metal Catalysts and Advanced Polyolefins - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Development of Late Transition Metal Catalysts and Advanced Polyolefins write by Nolan Evan Mitchell. This book was released on 2018. Development of Late Transition Metal Catalysts and Advanced Polyolefins available in PDF, EPUB and Kindle. This dissertation describes advances made within the Long Research Group to design single-site catalysts for olefin polymerizations, and for the synthesis of thermally cross-linkable polyolefins. We have 1) designed thermally robust Ni-based catalysts for ethylene polymerization, 2) expanded this thermal stability enhancement strategy to Co-based catalysts, and 3) developed thermally cross-linkable polyethylene that is facilitated by the rearrangement of a co-monomer. Catalysts employing late transition metals have been heavily studied for olefin polymerizations but their implementation in industry remains limited due to a variety of drawbacks. One specific limitation is the general thermal instability of these catalysts at temperatures commonly used for industrial polymerizations. We will herein demonstrate that the precatalyst bis[(2,6-dibenzhydryl-4-methylimino)acenaphthene] nickel(II) dibromide can be used to dramatically enhance the thermal stability of this family of Ni-based catalysts. This precatalyst proved to be thermally robust for ethylene polymerizations at temperatures as high as 90 °C and showing living polymerization behavior at temperatures as high as 75 °C. This bulky ligand was further expanded to sterically demanding Fe- and Co-based olefin polymerization catalysts bearing 2,6-bis(biphenylmethyl)-4-methylaniline substituted bis(imino)pyridine ligands were synthesized and evaluated for ethylene polymerization. Tthe extreme ligand bulk mitigated detectable chain-transfer to aluminum and associative chain-transfer events. These bulky Co catalysts display great thermal stability up to 80 °C and show enhanced thermal stability at 90 °C. These observations are attributed to the extreme steric demand by which the ligand mitigates catalyst transfer, deactivation, and decomposition. Lastly, materials that are accessible using catalysts currently employed in Industry. Industrial methods to cross-linked polyethylene are polymer irradiation and the incorporation of peroxides. These methods suffer from lack of control over cross-link bond formation and can result in a tacky polymer. We developed a thermally cross-linkable polyethylene that utilizes benzocyclobutene as a co-monomer. After polymerization, non-cross-linked films were formed and cross-linked by increasing the temperature to promote the thermal rearrangement of benzocyclobutene. These co-monomers can undergo cycloaddition with other activated benzocyclobutene co-monomers leading to covalently linked polyethylene chains. It will be demonstrated that cross-linking at temperatures above 200 °C yield cross-linked PEX films that show up to 82 % gel percent content.
Development of Late Transition Metal Insertion Polymerization Catalysts
Development of Late Transition Metal Insertion Polymerization Catalysts - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Development of Late Transition Metal Insertion Polymerization Catalysts write by Tobias Friedberger. This book was released on 2015. Development of Late Transition Metal Insertion Polymerization Catalysts available in PDF, EPUB and Kindle. Polyolefins are the number one commercially produced polymeric material by volume, and find ubiquitous uses as plastics, elastomers, and fibers. They are produced from gaseous olefins such as ethylene and propylene by the action of a transition metal catalyst. Despite tremendous academic and industrial efforts and successes in catalyst development over the past decades, the copolymerization of polar functionalized olefins with sufficiently high activities still remains a largely unsolved issue. Late transition metal catalysts were shown to be more suitable for this kind of polymerization reaction due to their generally lower oxophilic character. The main goal of this thesis was the development of novel late transition olefin polymerization catalysts based on ruthenium and palladium. Prior to this work, only few active olefin polymerization Ru-catalysts were reported. Several series of complexes based on ruthenium were synthesized, characterized and investigated for olefin polymerization. Ru(II)-complexes of the type RuCl2(N,N,N)L with facially coordinating nitrogen donor ligands (N,N,N = trispyridyl-, trispyrazoyl-, trisimidazoyl-methane derivatives) were found to be inactive towards ethylene polymerization. Employing bisanionic disulfonate phosphines as ligands gave Ru-complexes that produced linear, high-molecular weight polyethylene in the presence of an aluminum-alkyl based cocatalyst. Increasing the electrophilicity of the complex, by decreasing the donor strength of the ligand and using higher oxidation state Ru(IV)-complexes, the polymerization activity could be increased, and one of the highest activities for any Ru-based catalyst was observed. Polar additives such as acetone fully inhibited even the most electron-rich catalysts and copolymerization reactions yielded no polymer. In a different approach to solve the same problem, Pd-diimine complexes were modified with pendant olefin and boronate groups. Pd-diimine complexes can facilitate the copolymerization of ethylene with acrylates, and interactions of the pendant Lewis acid group with the functional, Lewis basic comonomer was anticipated to increase catalyst activity. However, no effect of a pendant pinacol boronate was observed on the incorporation ratio of methyl acrylate in room temperature copolymerizations. The ability of the pendant olefin to coordinate to cationic Pd-species resulted in hemilabile effects. Increased catalyst stability at the cost of decreased activities was found in comparison with unfunctionalized ligands.
Late Transition Metal Polymerization Catalysis
Late Transition Metal Polymerization Catalysis - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Late Transition Metal Polymerization Catalysis write by Bernhard Rieger. This book was released on 2006-03-06. Late Transition Metal Polymerization Catalysis available in PDF, EPUB and Kindle. 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.
