Download or read book Studies of Heterogenous Palladium and Related Catalysts for Aerobic Oxidation of Primary Alcohols written by Maaz S. Ahmed and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Development of aerobic oxidation methods is of critical importance for the advancement of green chemistry, where the only byproduct produced is water. Recent work by our lab has produced an efficient Pd based heterogenous catalyst capable of preforming the aerobic oxidation of a wide spectrum of alcohols to either carboxylic acid or methyl ester. The well-defined catalyst PdBi0.35Te0.23/C (PBT/C) catalyst has been shown to can perform the aerobic oxidation of alcohols to carboxylic acids in basic conditions. Additionally, we explored this catalyst for a wide range of alcohols and probed the nature of the selectivity of PBT/C for methyl esterification over other side products. Finally, means by which the catalyst operates with respect to oxidation states of the three components, Pd, Bi, and Te, was probed. Carboxylic acids are an important functional group due to their prevalence in various pharmaceutically active agents, agrochemicals, and commodity scale chemicals. The well-defined catalyst PBT/C catalyst was discovered to be effective for the oxidation of a wide spectrum of alcohols to carboxylic acid. The demonstrated substrate scope and functional group tolerance are the widest reported for an aerobic heterogeneous catalyst. Additionally, the catalyst has been implemented in a packed bed reactor with quantitative yield of benzoic acid maintained throughout a two-day run. Biomass derived 5-(hydroxymethyl)furfural (HMF) is also oxidized to 2,5-furandicarboxylic acid (FDCA) in high yield. Exploration of PBT/C for the oxidative methyl esterification was found to exhibit exquisite selectivity for the initial oxidation of primary alcohol instead of methanol, which is the bulk solvent. We explored this selectivity and conclude that it results from various substrate-surface interactions, which are not attainable by methanol. The primary alcohol can outcompete the methanol for binding on the catalyst surface through various interactions between the side chain of the alcohol solvent and the surface of the catalyst: (listed in order of strength) lone pair-surface (heterocyclic primary alcohols)> [pi]-surface (aryl primary alcohols)> van der Waals-surface (alkyl primary alcohols). These interactions were previously underappreciated in condensed phase heterogeneously catalyzed aerobic oxidations. Bi and Te serve as synergistic promoters that enhance both the rate and yield of the reactions relative to reactions employing Pd alone or Pd in combination with Bi or with Te as the sole promoter. We report X-ray absorption spectroscopic studies of the heterogenous catalyst. These methods show that the promoters undergo oxidation in preference to Pd, maintaining the Pd surface in the active metallic state and preventing inhibition by surface Pd-oxide formation. The data also suggest formation of a Pd-Te alloy phase that modifies the electronic properties of the Pd catalyst. Collectively, these results provide valuable insights into the synergistic benefits of multiple promoters in heterogeneous catalytic oxidation reactions.

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 Liquid Phase Aerobic Oxidation Catalysis written by Shannon S. Stahl and published by John Wiley & Sons. This book was released on 2016-10-10 with total page 454 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 Noble Metal Heterogeneous Catalysts for Aerobic Alcohol Oxidation written by and published by . This book was released on 2015 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: Transformation of hydrocarbon feedstocks to complex molecules found in the fine chemical, agro chemical, and pharmaceutical industries require selective oxidations to impart the desired functionality. Oxidation of alcohols is commonly done employing harsh and potentially hazardous oxidants with stoichiometric amounts of byproducts being produced. The use of O2 as the terminal oxidant provides a safe and environmentally benign alternative with selectivity control being realized through the use of a catalyst. The use of a Ru(OH)x/Al2O3 catalyst for the oxidation of alcohols to aldehydes or ketones was studied for applicability and scalability in a continuous process. The catalyst was found to undergo rapid deactivation in the first 50-100 turnovers. High yields of diverse aldehydes and ketones were realized in the continuous process over the deactivated Ru(OH)x/Al2O3 catalyst. The discovery of a new heterogeneous catalyst was accomplished through rapid admixture screening and optimization using design of experiment techniques. The optimized catalyst compositions of PdBi0.47Te0.09/C (PBT-1) and PdBi0.35Te0.23/C (PBT-2) were found to be very active and selective for the aerobic oxidation of 1-octanol to methyl octanoate. These optimized catalysts show high yields of many diverse methyl esters from the oxidation of alcohols, and their stability was demonstrated in a continuous process achieving nearly 60,000 turnovers with no apparent loss in activity. The role of the Bi and Te promoters and mechanism of the PBT-2 catalyst was explored through kinetic studies and characterization of the catalyst. Through the use of kinetics and other mechanistic probes we discovered that the reaction shows saturation dependence in [substrate] and [K2CO3] and is first order in pO2, supporting a Langmuir-Hinshelwood mechanism with the reaction occurring between alkoxide and O2 adsorbed to the catalyst. The promoters are proposed to protect the Pd catalyst from over oxidation to inactive PdOx species as well as prevent side reactions (Bi) and electronically modify the Pd (Te). Oxidation of alcohols to aldehydes or nitriles was demonstrated in a continuous process using a CuI/TEMPO catalyst. The oxidation to the nitrile was accomplished through the addition of anhydrous ammonia, and excellent yields were observed from the oxidation of diverse primary benzylic alcohols.

Download or read book Mechanistic Studies and Catalyst Development of Palladium catalyzed Aerobic C h Oxidations of hetero aromatics written by Dian Wang and published by . This book was released on 2017 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt: The selective oxidation of C-H bonds in (hetero)aromatics provides an efficient access to functionalized aromatic molecules of industrial interest. Aerobic oxygen is an ideal terminal oxidants for this transformation because it is readily available and often produces water as the sole byproduct. Homogeneous palladium catalysts are eminently compatible with aerobic turnovers and have seen success in numerous aerobic oxidation processes (e. g., alkene oxidation, alcohol oxidation). In contrast, palladium-catalyzed aerobic oxidative C-H functionalization has been rather underdeveloped. Challenges include slow catalytic turnover, catalyst decomposition and lack of selectivity control (e.g., site selectivity, homo- vs. cross-coupling selectivity). This thesis presents three research projects with different approaches to tackle the unsolved problems in the reaction class of palladium-catalyzed aerobic C-H oxidation of (hetero)aromatics. The reaction mechanism of C-H/C-H coupling of [o]-xylene was characterized, which disclosed a novel, bimetallic pathway. Built on this work, the effect of copper cocatalyst in this reaction was investigated, which revealed a non-traditional role of copper salt in oxidative palladium catalysis and led to the discovery of an improved catalyst system. Last, a synthetic methodology for aerobic indole C-H arylation with ligand-controlled site selectivity was developed, which provided efficient access to pharmaceutically-relevant aryl indoles and led to preliminary mechanistic insights into regiocontrol.

Download or read book Mechanistic Studies of Palladium catalyzed Aerobic Alcohol Oxidation written by Bradley A. Steinhoff and published by . This book was released on 2005 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Metal Organic Framework Materials written by Leonard R. MacGillivray and published by John Wiley & Sons. This book was released on 2014-09-19 with total page 1210 pages. Available in PDF, EPUB and Kindle. Book excerpt: Metal-Organic Frameworks (MOFs) are crystalline compounds consisting of rigid organic molecules held together and organized by metal ions or clusters. Special interests in these materials arise from the fact that many are highly porous and can be used for storage of small molecules, for example H2 or CO2. Consequently, the materials are ideal candidates for a wide range of applications including gas storage, separation technologies and catalysis. Potential applications include the storage of hydrogen for fuel-cell cars, and the removal and storage of carbon dioxide in sustainable technical processes. MOFs offer the inorganic chemist and materials scientist a wide range of new synthetic possibilities and open the doors to new and exciting basic research. Metal-Organic Frameworks Materials provides a solid basis for the understanding of MOFs and insights into new inorganic materials structures and properties. The volume also reflects progress that has been made in recent years, presenting a wide range of new applications including state-of-the art developments in the promising technology for alternative fuels. The comprehensive volume investigates structures, symmetry, supramolecular chemistry, surface engineering, recognition, properties, and reactions. The content from this book will be added online to the Encyclopedia of Inorganic and Bioinorganic Chemistry: http://www.wileyonlinelibrary.com/ref/eibc

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 Palladium Catalyzed Oxidation of Hydrocarbons written by P. Henry and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 449 pages. Available in PDF, EPUB and Kindle. Book excerpt: The field of organometallic chemistry has emerged over the last twenty-five years or so to become one of the most important areas of chemistry, and there are no signs of abatement in the intense current interest in the subject, particularly in terms of its proven and potential application in catalytic reactions involving hydrocarbons. The development of the organometallic/ catalysis area has resulted in no small way from many contributions from researchers investigating palladium systems. Even to the well-initiated, there seems a bewildering and diverse variety of organic reactions that are promoted by palladium(II) salts and complexes. Such homogeneous reactions include oxidative and nonoxidative coupling of substrates such as olefins, dienes, acetylenes, and aromatics; and various isomerization, disproportionation, hydrogenation, dehydrogenation, car bonylation and decarbonylation reactions, as well as reactions involving formation of bonds between carbon and halogen, nitrogen, sulfur, and silicon. The books by Peter M. Maitlis - The Organic Chemistry of Palladium, Volumes I, II, Academic Press, 1971 - serve to classify and identify the wide variety of reactions, and access to the vast literature is available through these volumes and more recent reviews, including those of J. Tsuji [Accounts Chem. Res. , 6, 8 (1973); Adv. in Organometal. , 17, 141 (1979)], R. F. Heck [Adv. in Catat. , 26, 323 (1977)], and ones by Henry [Accounts Chem. Res. , 6, 16 (1973); Adv. in Organometal. , 13, 363 (1975)]. F. R. Hartley's book - The Chemistry of Platinum and Palladium, App!. Sci. Pub!.

Download or read book Redox Active Ligands written by Marine Desage-El Murr and published by John Wiley & Sons. This book was released on 2024-01-31 with total page 373 pages. Available in PDF, EPUB and Kindle. Book excerpt: Redox-Active Ligands Authoritative resource showcasing a new family of ligands that can lead to better catalysts and promising applications in organic synthesis Redox-Active Ligands gives a comprehensive overview of the unique features of redox-active ligands, describing their structure and synthesis, the characterization of their coordination complexes, and important applications in homogeneous catalysis. The work reflects the diversity of the subject by including ongoing research spanning coordination chemistry, organometallic chemistry, bioinspired catalysis, proton and electron transfer, and the ability of such ligands to interact with early and late transition metals, lanthanides, and actinides. The book is divided into three parts, devoted to introduction and concepts, applications, and case studies. After the introduction on key concepts related to the field, and the different types of ligands and complexes in which ligand-centered redox activity is commonly observed, mechanistic and computational studies are described. The second part focuses on catalytic applications of redox-active complexes, including examples from radical transformations, coordination chemistry and organic synthesis. Finally, case studies of redox-active guanidine ligands, and of lanthanides and actinides are presented. Other specific sample topics covered include: An overview of the electronic features of redox-active ligands, covering their historical perspective and biological background The versatility and mode of action of redox-active ligands, which sets them apart from more classic and tunable ligands such as phosphines or N-heterocyclic carbenes Preparation and catalytic applications of complexes of stable N-aryl radicals Metal complexes with redox-active ligands in H+/e- transfer transformations By providing up-to-date information on important concepts and applications, Redox-Active Ligands is an essential reading for researchers working in organometallic and coordination chemistry, catalysis, organic synthesis, and (bio)inorganic chemistry, as well as newcomers to the field.

Download or read book New and Future Developments in Catalysis written by P. Štěpnička and published by Elsevier Inc. Chapters. This book was released on 2013-07-18 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Interfacial Catalysis written by Alexander G. Volkov and published by CRC Press. This book was released on 2002-12-12 with total page 690 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive volume on interfacial catalysis, this book includes contributions from an international group of specialists in chemistry, environmental science, informatics, physiology, nuclear energy, and physics. The editor has organized the material into the main topics of fundamental characteristics, phase transfer catalysis, reversed micelles, biological aspects, and interfacial photocatalysis. Individual topics include self-organized microheterogeneous structures, nanochemistry, interfacial catalysis in metal complexation, the role of water molecules in ion transfer at the oil/water interface, and ultrathin films in enhanced oil recovery.

Download or read book Metal Organic Frameworks as Heterogeneous Catalysts written by Francesc X. Llabrés i Xamena and published by Royal Society of Chemistry. This book was released on 2013-07-01 with total page 446 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book examines the latest research and discovery in the use of MOFs in catalysis, highlighting the extent to which these materials have been embraced by the community.

Download or read book Synthesis of Heterometallic Nitridoruthenium VI Complexes with Nickel Palladium Or Platinum written by Jesse Lee Kuiper and published by . This book was released on 2005 with total page 410 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Catalysts for Alcohol fuelled Direct Oxidation Fuel Cells written by Zhen-Xing Liang and published by Royal Society of Chemistry. This book was released on 2012 with total page 265 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a state-of-the-art review on recent advances in nanocatalysts and electrocatalysis in DOFCs.

Download or read book Oxidation of Primary Alcohols to Carboxylic Acids written by Gabriel Tojo and published by Springer Science & Business Media. This book was released on 2007-05-31 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: As the second volume in a comprehensive encyclopedia of organic reactions, this work provides an elaborated description of the experimental methods used for the oxidation of alcohols to acids. It supplies important data on possible interferences from protecting groups and functional groups, as well as on potential side-reactions. This book is a must for anyone involved in the preparation of organic compounds.

Download or read book The Design of Palladium and Copper catalyzed Atom Economical Reactions written by Boran Xu and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "This thesis describes the development of novel metal-catalyzed reactions in two different areas: palladium-catalyzed multicomponent coupling reactions, and copper-catalyzed aerobic oxidations of alcohols and amines. The goal of this work is to discover efficient processes to rapidly generate useful products with minimal waste. In chapter 2, we describe a straightforward new synthesis of 2-imidazolines. This reaction couples the palladium-catalyzed multicomponent formation of 2-imidazolium carboxylates, with subsequent decarboxylation. Polysubstituted imidazolines have useful applications in therapeutics, but are typically prepared in a multistep sequence. We report that the use benzoic acid and water as additives affords good yields and diastereoselectivities for the decarboxylation step. Combining this reaction with subsequent nitrogen deprotection, allows access to imidazolines from four available reagents: two imines, an acid chloride and CO. In chapter 3, we describe the three component palladium-catalyzed synthesis of [alpha]-amidostannanes from imines, acid chlorides and a bis-stannane. The reaction affords product in good yields, proceeds in 1 h, and uses simple Pd2(dba)3 as the catalyst. Mechanistically, this transformation occurs via a Stille-type cross-coupling of an in situ generated iminium salt with the bis-stannane. This represents a mild alternative to traditional syntheses of these products, with strong nucleophilic reagents. Subsequent lithiation and carboxylation can generate various [alpha]-amino acid derivatives in two steps from imines, acid chlorides and CO2. In chapter 4, we describe the copper-catalyzed aerobic oxidation of alcohols without the use nitroxyl co-catalysts. We demonstrate that a Cu/di-tert-butylethylenediamine (DBED) catalyst can generate active copper-oxygen species capable of mediating alcohol oxidation. This catalyst operates at ambient pressure and temperature and retains activity for challenging substrates such as secondary unactivated alcohols. Notably, this system likely operates via a distinct mechanistic pathway compared to nitroxyl based oxidations, and as a result, shows different alcohol chemoselectivity. In chapter 5, we describe the effects of the counterion (X-) in copper-catalyzed aerobic oxidation, and apply these to the oxidation of primary amines. By manipulating the copper salt employed, we have been able to design active catalysts for the oxidation of amines to nitriles (with CuI/DBED), or to imines (with CuPF6). Both of these reactions occur at unusually mild conditions (ambient temperature and pressure), and provide a practical approach to selective amine oxidation without added nitroxyl co-catalysts. " --