Download or read book Catalyst and Reactor Development for Aerobic Oxidation of Organic Substrates written by Yuliya Preger and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Safe and selective aerobic oxidation of organic substrates represents a grand challenge in catalysis. The productive utilization of oxygen is key to many, seemingly disparate, systems, for example, enzymatic catalysis, fine chemical production, and energy generation in fuel cells. This thesis describes new methods for carrying out aerobic oxidation in the latter two applications. Fuel cells are a promising technology for generating electrical energy from the energy in chemical bonds. However, the high loadings of Pt needed to catalyze oxygen reduction at the cathode have hindered broad adoption. To address this, a new fuel cell design was developed wherein oxygen reduction is executed off-electrode in an external reactor with non-Pt catalysts, using quinones as electron-proton transfer mediators. This represents the first instance of organic mediator use outside of low-power, enzymatic fuel cells. The latter part of this thesis details the development of new reactors and catalysts for general aerobic alcohol oxidations. Safe execution of aerobic oxidation in the presence of organic solvents is typically achieved by operating below the limiting oxygen concentration with inert diluents. 'Tube in shell' membrane reactors offer an intriguing alternative, permitting passage of O2 from the gas phase into a liquid-phase reaction through semi-permeable membranes. Use of a membrane reactor with inexpensive PTFE tubing enabled alcohol oxidation at rates an order of magnitude higher than previously reported. Heterogeneous catalysts, particularly noble metals such as Pt and Pd, have been extensively studied for alcohol oxidation. However, these catalysts exhibit low rates and limited substrate scopes due to poisoning by excess oxygen or various heterocycles; thus, various species were explored as catalyst 'promoters.' In the oxidative coupling of alcohols and ammonia to make nitriles, the addition of Bi to a Pt catalyst accelerated the rate of alcohol oxidation and enabled high yields with challenging heterocyclic alcohols. Furthermore, the addition of Bi and Te to a Pd catalyst increased the yield and rate for the oxidative coupling of alcohols with methanol to make methyl esters. Collectively, the above work highlights the opportunities for reaction engineering to enable the safe and selective utilization of oxygen in a range of chemistries.
Download or read book Liquid Phase Aerobic Oxidation Catalysis written by Shannon S. Stahl and published by John Wiley & Sons. This book was released on 2016-07-13 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first book to place recent academic developments within the context of real life industrial applications, this is a timely overview of the field of aerobic oxidation reactions in the liquid phase that also illuminates the key challenges that lie ahead. As such, it covers both homogeneous as well as heterogeneous chemocatalysis and biocatalysis, along with examples taken from various industries: bulk chemicals and monomers, specialty chemicals, flavors and fragrances, vitamins, and pharmaceuticals. One chapter is devoted to reactor concepts and engineering aspects of these methods, while another deals with the relevance of aerobic oxidation catalysis for the conversion of renewable feedstock. With chapters written by a team of academic and industrial researchers, this is a valuable reference for synthetic and catalytic chemists at universities as well as those working in the pharmaceutical and fine chemical industries seeking a better understanding of these reactions and how to design large scale processes based on this technology.
Download or read book Design and Development of Quinone Catalysts for Aerobic C N Bond Dehydrogenation Reactions written by and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The selective oxidation of organic compounds is a prominent challenge in organic chemistry. Towards this goal, molecular oxygen is an ideal oxidant. Uncatalyzed aerobic oxidation reactions have found important application in the commodity scale synthesis of certain compounds. However, such autoxidation reactions are intrinsically substrate-controlled. More frequently, selective aerobic oxidations are achieved by using a catalyst to promote the desired transformation. Under such a regime the identity of the catalyst -- and therefore the reaction mechanism -- dictates the chemical outcome of the reaction. The development of new catalysts which promote aerobic oxidation reactions is therefore of great significance. This thesis highlights two classes of catalyst that promote selective aerobic oxidation reactions. Chapters 1-4 describe the development of a family of o-quinone catalysts based on o-quinone cofactors found in certain oxidase and dehydrogenase enzymes. Unlike the natural cofactors, which have limited substrate scope, we find evidence for an unnatural reaction pathway that broadens the synthetic utility of these reagents. This family of bioinspired o-quinone catalysts is particularly effective in the aerobic dehydrogenation of C---N bonds. Subsequently, in chapters 5 and 6 I discuss the application of Cu-based catalysts to aerobic oxidation reactions, emphasizing an apparent mechanistic bifurcation between single electron transfer-based mechanisms and organometallic mechanisms within the published literature. Further work describes an application of CuII reagents in the aerobic oxidative cyclization of enamides to oxazoles.
Download or read book Frontiers of Green Catalytic Selective Oxidations written by Konstantin P. Bryliakov and published by Springer Nature. This book was released on 2019-10-02 with total page 295 pages. Available in PDF, EPUB and Kindle. Book excerpt: The demand for novel efficient and environmentally sustainable chemo, regio- and stereoselective catalyst systems for the oxidation of organic substrates is continuously growing in line with toughening economic and environmental constraints. This book addresses these issues; it consists of eleven chapters written by world-recognized experts in green and sustainable oxidation catalysis. The most urgent and challenging topics, in the judgment of the editor, such as green asymmetric epoxidations, sulfoxidatiuons, C–H oxidations; oxidation catalysis by polyoxometalates and oxidations in non-conventional solvents, etc. have been critically reviewed in this book. Both fundamental aspects, such as catalysts design, catalytic properties, nature of catalytically active sites and reaction mechanisms, and practical outlook of the oxidations have been addressed by the authors. The book appeals to a broad readership, particularly graduate students, employees of universities and research organizations, and industrial researchers, particularly those working in the areas of homogeneous oxidation catalysis, asymmetric synthesis, organocatalysis, sustainable catalytic processes and green chemistry, mechanisms of catalytic reactions, synthesis of bioactive compounds, biomimetic chemistry, etc. Konstantin Bryliakov is Leading Researcher at the Boreskov Institute of Catalysis. In 2016, he was elected Honorary Professor of the Russian Academy of Sciences.
Download or read book Catalytic Aerobic Oxidations written by Esteban Mejía and published by Royal Society of Chemistry. This book was released on 2020-07-14 with total page 349 pages. Available in PDF, EPUB and Kindle. Book excerpt: Oxidation reactions are an important chemical transformation in both academia and industry. Among the major advances in the field has been the development of catalytic processes, which are not only selective and efficient, but also allow the replacement of common stoichiometric oxidants with molecular oxygen, ideally from air at atmospheric pressure. This results in processes with higher atom efficiency, where water is the only side product in line with the principles of green chemistry. Focusing on the use of molecular oxygen as the terminal oxidant, this book covers recent advances in both heterogeneous and homogeneous systems, with and without metals and on the “taming” of the highly reactive oxygen gas by use of micro-flow reactors and membranes. A useful reference for industrial and academic chemists working on oxidation processes, as well as green chemists.
Download or read book Elucidating the Mechanisms of Copper catalyzed Aerobic Transformations written by and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The selective oxidation of organic molecules is a key challenge in the transformation of simple hydrocarbons to functionalized products. Copper catalysts are effective for the aerobic oxidations of organic substrates, including carbon-heteroatom bond-forming reactions and selective alcohol oxidations. Rigorous mechanistic understanding of these catalysts have more recently begun to guide reaction development of new classes of reactivity. The copper(II)-catalyzed oxidative coupling of boronic acids and heteroatom nucleophiles, the Chan-Evans-Lam reaction, is an alternative to non-oxidative cross-coupling technologies. Kinetic and spectroscopic (UV-visible, EPR, NMR) analysis of the reaction of 4-tolylboronic acid with methanol provides insight on the catalyst resting state(s) and steps preceding transmetalation (Chapter 2). The Chan-Lam reaction has an unpredictable substrate scope, and our results (Chapter 3) begin to rationalize the factors that govern the nucleophile reactivity, highlighting the inhibitory role of coordinating nucleophiles. Acidic nucleophiles form coupling products without interacting with the catalyst resting state. These results are in contrast to cross-coupling strategies, which are accelerated by coordination of donating nucleophiles. Homogeneous Cu/TEMPO catalysts have emerged as versatile and practical systems for aerobic alcohol oxidation. Our group has developed a CuI/TEMPO catalyst that oxidizes 1° aliphatic and benzylic alcohols with ambient air. Spectroscopic and kinetic measurements outline a two-stage mechanism that explains observed reactivity and directs further catalyst development (Chapter 4). CuI and TEMPO-H aerobic oxidation to make CuII and TEMPO, and substrate oxidation involving reaction of a CuII-alkoxide and TEMPO to make aldehyde, and reduced catalyst. Computational investigation (Chapter 5) of the substrate oxidation suggests TEMPO coordination to form a transient intermediate followed by facile hydride transfer.
Download or read book Mechanistic Studies of Cu catalyzed Aerobic Oxidation Reactions written by Scott Douglas McCann and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chemical copper-catalyzed aerobic oxidation reactions exhibit complexities not present in similar oxidation reactions employing noble metal catalysts with traditional chemical oxidants like hypervalent iodines or peroxides. The oxidation of organic molecules involves the removal of two protons and two electrons. This inevitably requires two CuII catalyst molecules to participate in the net oxidation reaction due to the one-electron redox-state changes typically associated with Cu. Additionally, CuI must react with molecular oxygen, a ground-state triplet molecule and net four-electron oxidant, to regenerate the active CuII catalyst. Aspects of these complexities are addressed in this thesis. Nature has evolved to use Cu catalysts (often together with redox-active organic cocatalysts) to perform oxidation reactions that use O2 as the terminal oxidant. The oxidation of CuI by O2 has been the subject of extensive investigation over the past several decades, and many of these studies were inspired by enzyme active sites in biological systems. Biological systems have also revealed pathways whereby CuII can oxidize organic substrates, and several chemical Cu-based catalyst systems exhibit intriguing similarities to enzymatic active sites. Herein, studies of several chemical copper-catalyzed aerobic oxidation reactions are reported, and, in many cases, the reactivity is compared to closely related enzymatic reactions. Chapter 1 summarizes challenges, opportunities, and progress made by our research group toward achieving selective and efficient Cu-catalyzed aerobic oxidation reactions. Chapter 2 describes a mechanistic study of aerobic alcohol oxidation catalyzed by Cu together with redox-active organic azodicarboxylates. Chapter 3 explains how Cu produces a redox-active organic nitroxyl cocatalyst under catalytic conditions from a simple diamine precursor. Chapter 4 details the investigation of single-electron transfer from phenol substrates to CuII.
Download or read book The Technology of Catalytic Oxidations written by Philippe Arpentinier and published by Editions Technip. This book was released on 2001 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volume 1 covers the most important technological aspects of the use of molecular oxygen for catalytic oxidation reactions.Volume 2 addresses the safety issues associated with the use of oxygen in catalytic oxidation reactions.Contents Vol. 1: 1. Introduction. 2. Chemical-physical properties of molecular oxygen. 3. Oxygen production technologies. 4. Chemical fundamentals of oxidation reactions. 5. Reactor technologies for multiphase systems. 6. Liquid phase oxidations. 7. Gas phase selective oxidations. 8. Selective oxidation of paraffins. References. Index. Vol. 2: 9. Introduction to safety problems in the chemical industry. 10. Chemical aspects of combustion in the gaseous phase. 11. Homogeneous chemical explosions: autoignition or spontaneous ignition. 12. Deflagration or propagation of flame. 13. Conditions governing flame propagation capability. 14. Detonation in the gaseous phase. 15. Prevention of and protection against explosions. References. Index.
Download or read book Transition Metal Catalysis in Aerobic Alcohol Oxidation written by Francesca Cardona and published by Royal Society of Chemistry. This book was released on 2015 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book deals with the search for environmentally benign procedures for the oxidation of alcohols and gives an overview of their transition-metal-catalyzed aerobic oxidation.
Download or read book Novel Iron pybisulidine Catalysts for the Selective Aerobic Oxidation and C O C C Cleavage of Organic Substrates written by Angela Gonzalez De Castro and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Catalytic Aerobic Oxidations written by Esteban Mejía and published by Royal Society of Chemistry. This book was released on 2020-07-15 with total page 349 pages. Available in PDF, EPUB and Kindle. Book excerpt: Oxidation reactions are an important chemical transformation in both academia and industry. Among the major advances in the field has been the development of catalytic processes, which are not only selective and efficient, but also allow the replacement of common stoichiometric oxidants with molecular oxygen, ideally from air at atmospheric pressure. This results in processes with higher atom efficiency, where water is the only side product in line with the principles of green chemistry. Focusing on the use of molecular oxygen as the terminal oxidant, this book covers recent advances in both heterogeneous and homogeneous systems, with and without metals and on the "taming" of the highly reactive oxygen gas by use of micro-flow reactors and membranes. A useful reference for industrial and academic chemists working on oxidation processes, as well as green chemists.
Download or read book The Role of Organic Cocatalysts in Homogeneous and Heterogeneous Oxidations written by Alexios Georgios Stamoulis and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Oxidation reactions are among the most important transformations in organic chemistry and have enormous potential to streamline the synthesis of complex organic molecules. Aerobic oxidations are especially appealing since they circumvent the use of toxic, stoichiometric reagents that result in poor atom economy and intractable waste. However, few aerobic oxidation methods employ catalysts with suitable stability, activity, and/or selectivity to impact industrial organic chemical synthesis. Metalloenzymes that catalyze selective aerobic oxidation reactions in nature often work cooperatively with redox-active cofactors and coenzymes to achieve efficient aerobic turnover and provide a valuable framework for development of new catalysts. Herein are reported studies of oxidation reactions featuring a homogeneous or heterogeneous catalyst working cooperatively with a homogeneous cocatalyst to enable efficient organic oxidation reactions. Chapter 1 highlights the challenges associated with developing efficient aerobic oxidation manifolds and analyzes the thermodynamic principles underlying catalytic aerobic oxidation reactions. A series of case studies are used to highlight the implications of catalyst and cocatalyst potentials on the activity and selectivity in the context of chemical synthesis. These insights are used as a backdrop for the content in subsequent chapters. Chapter 2 describes the first aerobic oxoammonium generation with a heterogeneous catalyst and lays the foundation for the content in Chapter 3, which discloses the first example of a metal on nitrogen-doped carbon (MNC) working cooperatively with a nitroxyl cocatalyst to effect alcohol oxidation. Chapter 4 details the development of an eminently scalable Pd/HQ-cocatalyzed cis-selective diacyloxylation of cyclohexadiene. Chapter 5 describes the study and development of a highly efficient palladium aerobic C-H arylation catalyst through the mechanistically-guided development of new quinone cocatalysts.
Download or read book The Catalytic Oxidation of Organic Substrates Utilizing Molecular Oxygen and Peroxides written by Douglas E. Patton and published by . This book was released on 1993 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Copper Mediated Cross Coupling Reactions written by Gwilherm Evano and published by John Wiley & Sons. This book was released on 2013-11-11 with total page 851 pages. Available in PDF, EPUB and Kindle. Book excerpt: Providing comprehensive insight into the use of copper in cross-coupling reactions, Copper-Mediated Cross-Coupling Reactions provides a complete up-to-date collection of the available reactions and catalytic systems for the formation of carbon-heteroatom and carbon-carbon bonds. This essential reference covers a broad scope of copper-mediated reactions, their variations, key advances, improvements, and an array of academic and industrial applications that have revolutionized the field of organic synthesis. The text also discusses the mechanism of these transformations, the use of copper as cost-efficient alternative to palladium, as well as recently developed methods for conducting copper-mediated reactions with supported catalysts.
Download or read book Copper Oxygen Chemistry written by Kenneth D. Karlin and published by John Wiley & Sons. This book was released on 2011-08-24 with total page 417 pages. Available in PDF, EPUB and Kindle. Book excerpt: Covers the vastly expanding subject of oxidative processes mediated by copper ions within biological systems Copper-mediated biological oxidations offer a broad range of fundamentally important and potentially practical chemical processes that cross many chemical and pharmaceutical disciplines. This newest volume in the Wiley Series on Reactive Intermediates in Chemistry and Biology is divided into three logical areas within the topic of copper/oxygen chemistry— biological systems, theory, and bioinorganic models and applications—to explore the biosphere for its highly evolved and thus efficient oxidative transformations in the discovery of new types of interactions between molecular oxygen and copper ion. Featuring a diverse collection of subject matter unified in one complete and comprehensive resource, Copper-Oxygen Chemistry probes the fundamental aspects of copper coordination chemistry, synthetic organic chemistry, and biological chemistry to reveal both the biological and chemical aspects driving the current exciting research efforts behind copper-oxygen chemistry. In addition, Copper-Oxygen Chemistry: Addresses the significantly increasing literature on oxygen-atom insertion and carbon-carbon bond-forming reactions as well as enantioselective oxidation chemistries Progresses from biological systems to spectroscopy and theory, and onward to bioinorganic models and applications Covers a wide array of reaction types such as insertion and dehydrogenation reactions that utilize the cheap, abundant, and energy-containing O2 molecule With thorough coverage by prominent authors and researchers shaping innovations in this growing field, this valuable reference is essential reading for bioinorganic chemists, as well as organic, synthetic, and pharmaceutical chemists in academia and industry.
Download or read book Development of Membrane Reactors for Heterogeneously Catalysed Aerobic Oxidation of Alcohols written by Gaowei Wu and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Oxidation of Alcohols to Aldehydes and Ketones written by Gabriel Tojo and published by Springer Science & Business Media. This book was released on 2006-06-15 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt: The aim of this book is to help people performing routine operations in Organic Synthesis in a laboratory. This book, the first one in a series, focuses on the oxidation of alcohols to aldehydes and ketones. Probably, this is the most important routine operation in Organic Synthesis.
