Download or read book A Study of Propane and Propene Ammoxidation Over the Mo V Nb Te oxide System written by Johan Holmberg and published by . This book was released on 2006 with total page 55 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Mechanism of Propane Ammoxidation Over the Ab Plane of the Mo V Te Nb O M1 Phase Probed by Density Functional Theory written by Junjun Yu and published by . This book was released on 2015 with total page 163 pages. Available in PDF, EPUB and Kindle. Book excerpt: The selective ammoxidation of propane into acrylonitrile catalyzed by the bulk Mo-V-Te-Nb-O system received considerable attention because it is more environmentally benign than the current process of propylene ammoxidation and relies on a more abundant feedstock. This process consists of a series of elementary steps including propane oxidative dehydrogenation (ODH), ammonia and O2 activation, and N-insertion into C3 surface intermediates. However, the limited fundamental understanding of the reaction mechanism and the roles of the different cations have hindered the progress in further improving the activity and selectivity of these catalysts required for the commercial application. In this thesis, we present and discuss the results of the density functional theory (DFT) calculations performed to investigate the overall propane ammoxidation pathway employing the cluster models of the proposed selective and active sites present in the surface ab plane of the so-called M1 phase, which is the main catalytic phase present in the bulk mixed Mo-V-Te-Nb oxides. The activation energies for the oxidative dehydrogenation (ODH) of propane and sequentially formed intermediates (isopropyl, propene, and allyl) were calculated for different surface cation sites. Propane activation on V5=O was found to be the rate-limiting step (Ea = 1.2 eV), consistent with the current proposed reaction mechanism for propane activation on the bulk mixed Mo-V-Te-Nb oxides and the current understanding of V5+ as the active site for alkane activation present in V-based mixed oxides. Furthermore, a linear relationship was established between the H adsorption energy and the activation energy for H abstraction from various C3 intermediates, which is highly useful for predicting the energy barriers of H abstraction from C3 species based solely on H adsorption energy. The energy barriers of ammonia activation on different surface sites and NH insertion into the allyl species were investigated and discussed in terms of the hypothetical reaction pathway reported in the literature. These elementary reaction steps were indicated to be energetically barrier-less. The formation of acrylonitrile over Te=O as the H abstraction site from the surface absorbed precursor was found to be a barrier-less step. The overall reaction pathway was then explored using micro-kinetic models to study the selectivity of propane ammoxidation to acrylonitrile on the Mo-V-Te-Nb-O M1 phase. The calculated coverages of surface intermediates on Mo and V active sites from the micro-kinetic model indicated that NH is the dominant species on the surface as compared to surface O species which may explain why the M1 phase is so selective in transforming the gas-phase p-allyl intermediate into acrylonitrile as opposed to combustion products. This thesis reports the very first theoretical study of a complete mechanism of propane ammoxidation over surface ab planes of bulk mixed Mo-V-Te-Nb-O M1 phase. Improved understanding of the surface structure - reactivity relationships for propane ammoxidation to acrylonitrile over this model mixed metal oxide system gained in this research offers a possibility of not only molecular engineering of such mixed metal oxide catalysts for propane (amm)oxidation, but also fundamentally advancing the field of selective alkane (amm)oxidation over bulk mixed metal oxides.
Download or read book A Study of Propane and Propene Ammoxidation Over Antimony vanadium oxide Catalysts at Steady state and Transient Conditions written by Roland Nilsson and published by . This book was released on 1997 with total page 37 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Surface Termination of M1 Phase and Rational Design of Propane Ammoxidation Catalysts written by and published by . This book was released on 2015 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: This final report describes major accomplishments in this research project which has demonstrated that the M1 phase is the only crystalline phase required for propane ammoxidation to acrylonitrile and that a surface monolayer terminating the ab planes of the M1 phase is responsible for their activity and selectivity in this reaction. Fundamental studies of the topmost surface chemistry and mechanism of propane ammoxidation over the Mo-V-(Te,Sb)-(Nb,Ta)-O M1 and M2 phases resulted in the development of quantitative understanding of the surface molecular structure – reactivity relationships for this unique catalytic system. These oxides possess unique catalytic properties among mixed metal oxides, because they selectively catalyze three alkane transformation reactions, namely propane ammoxidation to acrylonitrile, propane oxidation to acrylic acid and ethane oxidative dehydrogenation, all of considerable economic significance. Therefore, the larger goal of this research was to expand this catalysis to other alkanes of commercial interest, and more broadly, demonstrate successful approaches to rational design of improved catalysts that can be applied to other selective (amm)oxidation processes.
Download or read book Handbook Of Advanced Methods And Processes In Oxidation Catalysis From Laboratory To Industry written by Daniel Duprez and published by World Scientific. This book was released on 2014-07-24 with total page 1035 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book offers a comprehensive overview of the most recent developments in both total oxidation and combustion and also in selective oxidation. For each topic, fundamental aspects are paralleled with industrial applications. The book covers oxidation catalysis, one of the major areas of industrial chemistry, outlining recent achievements, current challenges and future opportunities. One distinguishing feature of the book is the selection of arguments which are emblematic of current trends in the chemical industry, such as miniaturization, use of alternative, greener oxidants, and innovative systems for pollutant abatement. Topics outlined are described in terms of both catalyst and reaction chemistry, and also reactor and process technology.
Download or read book Catalysis written by and published by Royal Society of Chemistry. This book was released on 2015-02-05 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt: Industrial and academic scientists face increasing challenges to find cost-effective and environmentally sound methods for converting natural resources into fuels, chemicals and energy. With over 7000 papers published in this field of catalysis each year, keeping up with the literature can be difficult. Catalysis Volume 27 presents critical and comprehensive reviews of the hottest literature published over the last twelve months. Covering major areas such as chemical transformations using two-dimensional hybrid nanocatalysts, conversion of biomass-derived syngas to fuels and catalytic oxidation of organic pollutants in aqueous solution using sulfate radicals, this book is a useful reference for anyone working in catalysis and an essential resource for any library.
Download or read book Metal Oxides in Heterogeneous Catalysis written by Jacques C. Vedrine and published by Elsevier. This book was released on 2018-01-11 with total page 620 pages. Available in PDF, EPUB and Kindle. Book excerpt: Metal Oxides in Heterogeneous Catalysis is an overview of the past, present and future of heterogeneous catalysis using metal oxides catalysts. The book presents the historical, theoretical, and practical aspects of metal oxide-based heterogeneous catalysis. Metal Oxides in Heterogeneous Catalysis deals with fundamental information on heterogeneous catalysis, including reaction mechanisms and kinetics approaches.There is also a focus on the classification of metal oxides used as catalysts, preparation methods and touches on zeolites, mesoporous materials and Metal-organic frameworks (MOFs) in catalysis. It will touch on acid or base-type reactions, selective (partial) and total oxidation reactions, and enzymatic type reactions The book also touches heavily on the biomass applications of metal oxide catalysts and environmentally related/depollution reactions such as COVs elimination, DeNOx, and DeSOx. Finally, the book also deals with future trends and prospects in metal oxide-based heterogeneous catalysis. - Presents case studies in each chapter that provide a focus on the industrial applications - Includes fundamentals, key theories and practical applications of metal oxide-based heterogeneous catalysis in one comprehensive resource - Edited, and contributed, by leading experts who provide perspectives on synthesis, characterization and applications
Download or read book International Assessment of Research and Development in Catalysis by Nanostructured Materials written by Robert Davis and published by World Scientific. This book was released on 2011 with total page 329 pages. Available in PDF, EPUB and Kindle. Book excerpt: Catalyst technologies account for over $1 trillion of revenue in the U.S. economy alone. The applications range from medicines and alternative energy fuel cell technologies to the development of new and innovative clothing fibers. In this book, a World Technology Evaluation Center (WTEC) panel of eight experts in the field assesses the current state of research and development in catalysis by nanostructured materials, its sources of funding, and discusses the state of the field with respect to productivity and leadership in various nations around the world. In addition to showing the numerous and highly advantageous practical applications of the field, the panel concludes that Western Europe is currently the most productive region, followed closely by the United States. Still, the research and development output of the People's Republic of China has recently surpassed that of Japan and is now poised to surpass that of the U.S. as well. As such, this assessment is a timely review of the field's progress, taking into account the increasing contributions from Asia, and will be essential reading for professionals, whether they are seeking an in-depth summary of the state of the art or a broad view of trends affecting the discipline.
Download or read book Molecular Structure reactivity Relationships for Propane Oxidation Over Model Mixed Oxide Catalysts written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Mixed Mo-V-Sb-Nb and Mo-V-Te-Nb oxides were recently discovered as highly active and selective catalysts for the propane oxidation to propylene and oxygenates, i.e. acrolein and acrylic acid. Fundamental information is needed for understanding the bulk and surface molecular structure-activity/selectivity relationships and providing rules of rational design of improved mixed metal oxide catalysts for the selective oxidation of propane. The phase composition and catalytic activity of the model Mo-V-Sb-Nb-O system strongly depended on the synthesis route and composition. A number of distinct solid-state phases were observed in this system: Mo6V9O40, MoO3, rutile SbVO4 and the defect "Mo-V-Nb-O" phases. The kinetic studies indicated that the high selectivity to acrylic acid (2̃0 mol.%) was associated with the Mo6V9O40 and the defect "Mo-V-Nb-O" phases. The synthesis of these mixed Mo-V-Sb-Nb-O system was performed using combinatorial chemistry techniques to explore the utility of liquid phase automated synthesis for the reproducible preparation of these catalysts. This study indicated good reproducibility of phase compositions and catalytic properties and provided new insights into the transformation processes that occur in these oxides with time on stream. It was discovered in this research that the model mixed Mo-V-Te-O catalyst represents a simple model system for elucidating the molecular structure-activity/selectivity relationships in propane selective oxidation. This catalyst contains the two major crystalline phases proposed as active and selective for propane oxidation. This research elucidated the effect of the chemical composition, solution pH and thermal treatment on phase composition and catalytic performance. High resolution TEM study established the crystal structures of the hexagonal and orthorhombic phases in terms of their space groups, unit cell parameters, atomic coordinates and elemental compositions. In order to understand the role of the structure, morphology and composition of mixed Mo-V-Te-Nb-O system, novel synthesis approaches employing ordered arrays of colloidal polystyrene spheres (0.4 ưm) were successfully developed. These novel nanocrystalline catalysts with surface areas in the 80-110 m2/g range consisted of 20-50 nm particles of desirable catalytic phases and contained 6-20 nm pores. Kinetic studies demonstrated the acrylic acid yields exceeding 40 mol.% and approaching the commercial targets for the selective oxidation of propane to acrylic acid.
Download or read book Nanotechnology in Catalysis 3 Volumes written by Bert F. Sels and published by John Wiley & Sons. This book was released on 2017-10-16 with total page 1180 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dieses Handbuch präsentiert die in den letzten zehn Jahren entstandenen neuen Anwendungsbereiche und gibt einen umfassenden Überblick über dieses wissenschaftlich und ökonomisch wichtige Gebiet. Einzigartig ist die Verbindung von Grundlagenforschung und industrieller Entwicklung.
Download or read book Metal Oxides written by J.L.G. Fierro and published by CRC Press. This book was released on 2005-08-24 with total page 808 pages. Available in PDF, EPUB and Kindle. Book excerpt: The chemistry of metals has traditionally been more understood than that of its oxides. As catalytic applications continue to grow in a variety of disciplines, Metal Oxides: Chemistry and Applications offers a timely account of transition-metal oxides (TMO), one of the most important classes of metal oxides, in the context of catalysis. The
Download or read book Nanocatalysis written by Vanesa Calvino-Casilda and published by CRC Press. This book was released on 2019-02-14 with total page 241 pages. Available in PDF, EPUB and Kindle. Book excerpt: Synthesis and design of new nanocatalysts is an important area of research that aims to introduce multiple types of useful applications in a greener market. The necessity of nanostructuring the active sites has emerged as the key point in a successful design of the catalysts. The book covers the progress in this research area done in the last ten years. It includes the classification of catalysts and structure of active sites at the nanoscale. The book covers examples to present the concept, evolution of nanocatalysts from the perspective of chemistry of materials and their applications.
Download or read book Tellurium Chemistry written by Bimal Krishna Banik and published by Walter de Gruyter GmbH & Co KG. This book was released on 2022-10-03 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt: Tellurium, a well-known chalcogen, finds potential applications in various fields from chemistry to other branches of science such as nanotechnology and macromolecular science. However, its safety must also be taken into consideration when exploring its industrial applications. This book explores the breadth of tellurium's applications, outlines strategies for industrial use, and describes the safety concerns of this element.
Download or read book Metal Oxide Catalysis 2 Volume Set written by S. David Jackson and published by John Wiley & Sons. This book was released on 2008-12-23 with total page 887 pages. Available in PDF, EPUB and Kindle. Book excerpt: With its two-volume structure, this handbook and ready reference allows for comprehensive coverage of both characterization and applications, while uniform editing throughout ensures that the structure remains consistent. The result is an up-to-date review of metal oxides in catalysis. The first volume covers a range of techniques that are used to characterize oxides, with each chapter written by an expert in the field. Volume 2 goes on to cover the use of metal oxides in catalytic reactions. For all chemists and engineers working in the field of heterogeneous catalysis.
Download or read book Nanotechnology in Catalysis written by Bert Sels and published by John Wiley & Sons. This book was released on 2017-06-21 with total page 1500 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reflecting the R&D efforts in the field that have resulted in a plethora of novel applications over the past decade, this handbook gives a comprehensive overview of the tangible benefits of nanotechnology in catalysis. By bridging fundamental research and industrial development, it provides a unique perspective on this scientifically and economically important field. While the first three parts are devoted to preparation and characterization of nanocatalysts, the final three provide in-depth insights into their applications in the fine chemicals industry, the energy industry, and for environmental protection, with expert authors reporting on real-life applications that are on the brink of commercialization. Timely reading for catalytic chemists, materials scientists, chemists in industry, and process engineers.
Download or read book Catalytic Studies of Propane Oxidation to Acrylic Acid on Mo V Sb Nb Mixed Oxides Catalysts written by Ekaterina Krasteva Novakova and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Innovative Applications of Mo W Based Catalysts in the Petroleum and Chemical Industry Emerging Research and Opportunities written by Ge, Hui and published by IGI Global. This book was released on 2017-02-08 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mo(W)-Based Catalysts have the capacity to drastically impact many different industries. Research on their most current applications is important for the success of many organizations and companies, specifically the chemical and petroleum industries. Innovative Applications of Mo(W)-Based Catalysts in the Petroleum and Chemical Industry: Emerging Research and Opportunities is an informative resource that overviews emerging methods and techniques that incorporate 2D layer Mo(W) dichalcogenides. Featuring extensive coverage on a range of subjects including 2D nanosheets, hybridization, dichacogenides, and oxide based catalysts, this is an ideal publication for academicians, students, engineers, and researchers seeking insight on the latest advancements in Mo(W)-Based catalyst applications.
