Download or read book Kinetics of Metal Atom Oxidation Reactions written by Arthur Fontijn and published by . This book was released on 1972 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: The tubular fast-flow reactor, previously used for reaction kinetic measurements at temperatures up to only 1000K, has been adapted to reach temperatures up to 2000K and has been applied to studies of gas phase reactions of metal atoms with O2. The most extensive set of results obtained so far is for the Fe/O2 reaction in an N2 bath at 1600K. Preliminary results for the Al reaction with O2 at 1700K are discussed. The experimental technique described here allows measurements to be made under reaction conditions overlapping those used in flame and shock-tube studies. A design study for a wall-less reactor which would allow extension of metal atom oxidation studies down to about 200 to 300K is also reported. (Author).

Download or read book Kinetics of Some Metal Atom and Metal Fluoride Oxidation Reactions Relevant to Air Force Technology Development written by Arthur Fontijn and published by . This book was released on 1979 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: This experimental work is providing kinetic data on metal oxidation reactions for Air Force rocket propulsion and ramjet technology programs using the HTFFR (High-Temperature Fast-Flow Reactor) technique over the temperature range 300 to 1900 K. The reaction mechanisms and rate coefficients have been obtained from optical absorption and fluorescence measurements of the consumption of metal atoms or metal monoxide/monohalide radicals, as functions of pressure, oxidizer concentration, reaction time, and temperature; these variables are independently controlled.

Download or read book Kinetic Aspects of Gas Phase Metal Atom Oxidation Reactions written by John Wiesenfeld and published by . This book was released on 1979 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: The oxidation of Ge and Sn by various gases including N2O, has been studied by flash photolysis at room temperature and the kinetics determined. The rate of Sn + N2O is probably too slow to permit construction of a chemical laser based on this reaction. A new set of techniques involving laser pumping of alkaline earth atoms is also described which will permit the study of the kinetic behavior of their low-lying excited levels in bimolecular collisions. (Author).

Download or read book Kinetics of Some Metal Atom and Metal Fluoride Oxidation Reactions Relevant to Air Force Technology Development written by William Felder and published by . This book was released on 1981 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Kinetics of Metal Oxidation Reactions written by Biljana Cosic and published by . This book was released on 2004 with total page 139 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Gas Phase Metal Reactions written by A. Fontijn and published by Elsevier. This book was released on 2017-05-04 with total page 711 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book brings together, for the first time, all aspects of reactions of metallic species in the gas phase and gives an up-to-date overview of the field. Reactions covered include those of atomic, other free radical and transient neutral species, as well as ions. Experimental and theoretical work is reviewed and the efforts to establish a closer link between these approaches are discussed. The field is mainly approached from a fundamental point-of-view, but the applied problems which have helped stimulate the interest are pointed out and form the major subject of the final chapters. These emphasize the competition between purely gas-phase and gas-surface reactions.

Download or read book Kinetics of Iron and Aluminum Oxidation by Oxygen written by Arthur Fontijn and published by . This book was released on 1971 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt: Because of the need for quantitative information on gaseous metal atom oxidation kinetics, an experimental research program has been initiated to determine the mechanism and rate coefficients of the homogeneous reactions of free Fe and Al atoms with O2. The apparatus used is a cylindrical fast-flow reactor, adapted for the study of the kinetics of refractory gaseous species at temperatures up to 1900 K. The Fe/O2 reaction at 1600 K was investigated in N2/O2 flows by observing the rate of decay of Fe-atom concentrations, measured in absorption, at pressures from 15 to 60 Torr. The gas phase reaction has been determined to be Fe + O2 yields FeO + O, with a rate coefficient k sub 2=4 x 10 to the minus 13 power ml/molecule/sec. This result is estimated to be accurate to within a factor of about 2. Evidence for heterogeneous oxidation of Fe in the presence of O2 has also been obtained; the lower limit for the probability of Fe oxidation per collision with the reactor wall, is found to be on the order of 1/10. (Author).

Download or read book Reactions of Metallic Salts and Complexes and Organometallic Compounds written by C.H. Bamford and published by Elsevier. This book was released on 1972-01-15 with total page 633 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reactions of inert complexes and metal organic compounds / C.H. Langford, M. Parris -- Reactions in solution between various metal ions of the same element in different oxidation states / P.J. Proll -- Oxidation-reduction reactions between complexes of different metals / D. Benson -- Oxidation-reduction reactions between covalent compounds and metal ions / T.J. Kemp -- Induced reactions / L.J. Csányi.

Download or read book Kinetics and Mechanism in the Oxidation of Metal Vapors written by and published by . This book was released on 1974 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: In an effort to understand the kinetics and mechanisms of gas-phase metal oxidation reactions, experiments were continued in an apparatus which uses RF heating and laser radiation for the production of the metal vapor and time- of-flight mass spectrometry for product identification and quantitative measurements of reactants and products. Measurements were continued on the oxidation of thorium and uranium by molecular and atomic oxygen, as well as N2O and rate constants were measured.

Download or read book NBS Special Publication written by and published by . This book was released on 1968 with total page 414 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Chemical Kinetics and Inorganic Reaction Mechanisms written by Smiljko Asperger and published by Springer Science & Business Media. This book was released on 2011-06-27 with total page 363 pages. Available in PDF, EPUB and Kindle. Book excerpt: The serious study of the reaction mechanisms of transition metal com plexes began some five decades ago. Work was initiated in the United States and Great Britain; the pioneers ofthat era were, inalphabetical order, F. Basolo, R. E. Connick, 1. O. Edwards, C. S. Garner, G. P.Haight, W. C. E. Higgision, E.1. King, R. G. Pearson, H. Taube, M.1. Tobe, and R. G. Wilkins.A larger community of research scientists then entered the field, many of them stu dents ofthose just mentioned. Interest spread elsewhere as well, principally to Asia, Canada, and Europe. Before long, the results ofindividual studies were being consolidated into models, many of which traced their origins to the better-established field of mechanistic organic chemistry. For a time this sufficed, but major revisions and new assignments of mechanism became necessary for both ligand sub stitution and oxidation-reduction reactions. Mechanistic inorganic chemistry thus took on a shape of its own. This process has brought us to the present time. Interests have expanded both to include new and more complex species (e.g., metalloproteins) and a wealth of new experimental techniques that have developed mechanisms in ever-finer detail. This is the story the author tells, and in so doing he weaves in the identities of the investigators with the story he has to tell. This makes an enjoyable as well as informative reading.

Download or read book Kinetics of Al Atom Oxidation written by Arthur Fontijn and published by . This book was released on 1973 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: The kinetics of the Al/O2 reaction system has been studied with the AeroChem high-temperature fast-flow reactor (an adaptation of the steady-state flow reactor suitable for measurements at temperatures up to 2000K). The rate coefficient for the homogeneous gas-phase reaction Al + O2 to AlO + O has been determined. Evidence for a zero-order and a first order wall Al-oxidation process were also obtained. Comparison is made to other metal atom oxidations. (Modified author abstract).

Download or read book Surface Reactions written by R.J. Madix and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 291 pages. Available in PDF, EPUB and Kindle. Book excerpt: A treatment of the important aspects of physical chemistry on metal surfaces, including selective oxidation, desulfurization, cyclization, metal-organic chemical vapor deposition, alkane activation and hydrogen dissociation dynamics. Case studies focus on on the chemistry of selected systems, rather than the techniques, to convey the excitement of recent developments.

Download or read book Combustion Kinetics of Metal Oxide and Halide Radicals and Metal Atoms written by Arthur Fontijn and published by . This book was released on 1986 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: To help provide a better understanding of the temperature dependence of the kinetics of diatomic metal radical oxidation reactions, experimental measurements were made in the 450 to 1750 K temperature regime. An HTFFR (high-temperature fast-flow reactor) was used. The metal radical concentrations were measured by laser-induced fluorescence. The general uses of this spectrometric technique for rate measurements on reactants and products, as well as for product species identification and product state determination, are reviewed. The radicals studied in the HTFFR on this grant are ALo, AlCl and BCl. Production methods for these are discussed. For the reaction AlO + CO yields AlO2 AlO + AlO2 + CO we obtain k(T) = 2.5 X 10 to the minus 14th power exp (400/T) cc/molecules/s. This negative activation energy implies D(O-AlO)> D(O-CO) = 530 kj/mol, which is in apparent disagreement with the OAlO dissociation energy obtained for AlO2 from Al2O3 evaporation-mass spectrometry studies. It is argued that the latter AlO2 may have a different structure from that of the present work. For the reaction between AlCl and O2 we find k(T) = 6.8 X 10 to the minus 13th power exp( -2990/T) + 1.5 X 10 to the minus 10th power exp( -10600/T) cc/mol/s, which is compatible with a mechanisms where the Al02 + Cl product channel dominates at lower temperatures, while the OAlCl + O channel dominates at higher temperatures. The ln k(T) versus dependence of the AlCl/O2 reaction is contrasted to those observed for AlO/O2 and BF/02 reactions.

Download or read book Kinetic Consequences of Chemisorbed Oxygen Atoms During Methane Oxidation on Group VIII Metal Clusters written by Ya Huei Chin and published by . This book was released on 2011 with total page 394 pages. Available in PDF, EPUB and Kindle. Book excerpt: Molecular insights and the kinetic relevance of reaction elementary steps for methane activation on Group VIII metal and oxide clusters are established based on kinetic, isotopic, and theoretical assessments. These fundamental understandings enable accurate prediction of complex rate dependencies and cluster size effects during methane conversion reactions in catalytic partial oxidation, reforming, and combustion processes. Kinetics of methane reactions with oxygen are described by several regimes, each with unique rate dependencies and kinetic requirements, as the identities of the kinetically-relevant step and the most abundant surface intermediates vary with the surface and bulk oxygen contents of Pt and Pd clusters. C-H bond activation is the kinetically-relevant step in all regimes except for one that occurs immediately before the complete oxygen depletion. C-H bond activation steps may, however, proceed via mechanistically distinct paths of oxidative insertion of metal atom, oxidative insertion coupled with H abstraction, or H abstraction routes, over metal-metal, oxygen-metal, or oxygen-oxygen site pairs, respectively, thus exhibiting different activation enthalpies and entropies. The predominant route for C-H bond activation is dictated by the coverages and reactivities of oxygen on cluster surfaces and accessibility of metal atom to methane reactants. In a narrow regime before the complete oxygen consumption, C-H bond activation becomes kinetically inconsequential on oxygen-depleted surfaces and oxygen dissociative-adsorption steps limit methane conversion rates. The relation among oxygen coverages, oxygen reactivities, and methane reaction paths leads to a single-valued functional dependence of reactive methane collision probabilities on oxygen chemical potentials at the cluster surfaces. The oxygen chemical potentials are given by kinetic coupling of the generation and removal of reactive oxygen atoms and thus are kinetic properties of methane reactions; they become a thermodynamic property only in the limiting case of equilibrated oxygen dissociative-recombination steps. The fate of oxygen during catalysis was rigorously defined as the reactive collision probabilities for CO oxidation relative to those for methane and was measured at low oxygen coverages on Pt in which CO is most likely to desorb before encountering an oxygen atom and undergoing further oxidation to carbon dioxide. The reactive collision probabilities are much larger for CO oxidation than for methane oxidation; these results have unequivocally confirmed that CO and hydrogen, if formed on and desorbed from catalytic surfaces, rapidly undergo sequential oxidation to form carbon dioxide and water and that direct CO and hydrogen formation via molecular coupling of methane and oxygen is impractical at any residence time required for practical extents of methane conversion. Thermodynamics of oxygen dissolution from cluster surfaces into the bulk, cluster size and metal coordination effects on thermodynamic tendencies of bulk oxidation, and their catalytic consequences are established on Pd clusters. Oxidation of Pd clusters occurs via gradual dissolution of chemisorbed oxygen atoms into the bulk phase over a wide range of oxygen chemical potentials. The oxygen dissolution steps initiate and complete at lower oxygen chemical potentials in small than large clusters, indicating that small clusters exhibit a higher thermodynamic tendency for bulk oxidation. Oxygen dissolution leads to more weakly bound surface oxygen atoms and to exposed Pd atoms. These Pd atoms, together with vicinal lattice oxygen atoms, form Pd-oxygen site pairs that are more effective for C-H bond activation than O*-O* sites prevalent on metallic Pd cluster surfaces via concerted steps of an oxidative insertion of Pd atoms into the C-H bonds and oxygen assisted H abstraction. As oxygen binding strength decreases and Pd atoms become accessible with increasing oxygen contents in the clusters, C-H bond activation rate constants increase over the entire range of O-to-Pd atomic ratios throughout the Pd-to-PdO phase transition. This fundamental study describes how oxygen thermochemical properties influence active site structures and, in turn, dictate the kinetics of methane oxidation reactions. The direct relation between the oxygen thermochemical properties and methane oxidation kinetics has not been previously interpreted at the atomic scale; this relation appears to be general for alkane oxidation reactions over transition metal and oxide clusters, as has been shown also in our recent work on ethane oxidation.

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1992 with total page 1572 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Technical Abstract Bulletin written by and published by . This book was released on with total page 1048 pages. Available in PDF, EPUB and Kindle. Book excerpt: