Download or read book FT IR Studies on Partial Oxidation of Methane Over Ferric Molybdate Catalysts written by Surajit Fuangfoo and published by . This book was released on 1997 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt: The reactions of methane on Fe$\sb2$O$\sb3$, MoO$\sb3$ and ferric molybdate catalysts were studied in situ using the Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) technique. The ferric molybdate catalysts were prepared by coprecipitation of ferric nitrate and ammonium paramolybdate solutions. The experiments were carried out at the temperatures of 673, 703 and 743 K, and at the pressure of 1 and 3 MPa. This study revealed that MoO$\sb3$ is the active catalyst for the partial oxidation of methane to formaldehyde and Fe$\sb2$O$\sb3$ gives carbon dioxide. Both methanol and formaldehyde can be obtained from the ferric molybdate catalysts. The formation of methoxy (OCH$\sb3$), adsorbed formaldehyde, dioxymethylene (OCH$\sb2$O), and formate (OCHO) species were observed on the catalyst surface. A mechanism based on the reaction of methane with the surface of the ferric molybdate catalysts to produce methoxy groups which are further oxidized to dioxymethylene was proposed. The formation of carbon oxides is attributed to either the decomposition of dioxymethylene or to the formation of formate species. The kinetic parameters of the elementary reactions in the proposed mechanism were determined.
Download or read book Dynamics of Surfaces and Reaction Kinetics in Heterogeneous Catalysis written by G.F. Froment and published by Elsevier. This book was released on 1997-09-03 with total page 611 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many processes of the chemical industry are based upon heterogeneous catalysis. Two important items of these processes are the development of the catalyst itself and the design and optimization of the reactor. Both aspects would benefit from rigorous and accurate kinetic modeling, based upon information on the working catalyst gained from classical steady state experimentation, but also from studies using surface science techniques, from quantum chemical calculations providing more insight into possible reaction pathways and from transient experimentation dealing with reactions and reactors. This information is seldom combined into a kinetic model and into a quantitative description of the process. Generally the catalytic aspects are dealt with by chemists and by physicists, while the chemical engineers are called upon for mechanical aspects of the reactor design and its control. The symposium "Dynamics of Surfaces and Reaction Kinetics in Heterogeneous Catalysis" aims at illustrating a more global and concerted approach through a number of prestigious keynote lectures and severely screened oral and poster presentations.
Download or read book Study of Molybdate Catalyst for the Partial Oxidation of Methane written by Anand S. Chellappa and published by . This book was released on 1993 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dissertation Abstracts International written by and published by . This book was released on 1999 with total page 892 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book In Situ Infared i e Infrared Studies of Catalytic Partial Oxidation written by Chundi Cao and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Catalytic partial oxidation (CPO) has received considerable interest recently both as a way to utilize remote natural gas resources and to provide H[subscript]2 for a fuel cell. Studies on the reactions at lower temperatures and transient conditions were performed, which can provide insights on the mechanism of CPO at high reactions, particularly on the role of the chemical and physical state of the noble metal catalyst. In this work, ignition of methane CPO on Pt/Al[subscript]2O[subscript]3 and Rh/Al[subscript]2O[subscript]3 catalysts and methanol CPO on Pt/Al[subscript]2O[subscript]3 catalysts were studied using in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The ignition mechanism study of CH4 on Pt/Al[subscript]2O[subscript]3 showed that oxygen mainly covers the surface until ignition. Competition between the two reactants is assumed. The heat of adsorption of oxygen is a key factor for ignition of the methane partial oxidation reaction on Pt/Al[subscript]2O[subscript]3. The ignition mechanism on Rh/Al[subscript]2O[subscript]3 was found to be different from Pt/Al[subscript]2O[subscript]3. The oxidation state of the catalyst changed significantly as the temperature was raised towards the ignition. An oxidized rhodium state, Rh[superscript]n+, progressively formed as the temperature was increased while Rh[superscript]0 decreased. In addition, a greater amount of Rh[supercript]n+ was found when the oxygen concentration in the feed was higher. From these results, it is hypothesized that ignition of methane CPO on Rh/Al[subscript]2O[subscript]3 is related to the accumulation of the Rh[superscript]n+ state. Dissociation adsorption of methanol occurs on both Al2O3 and Pt/Al[subscript]2O[subscript]3. It is suggested that formate was one of the important intermediates in the reaction pathway. Oxygen species play a key role in the formation of formate on the catalysts, and it also affects the product composition. Formate mainly decomposed into CO, which is the dominant source for CO[subscript]2 production in the reactions at higher temperatures.
Download or read book Short Contact Time written by Ivan Tavazzi and published by . This book was released on 2005 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Methane Conversion by Oxidative Processes written by Wolf and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 556 pages. Available in PDF, EPUB and Kindle. Book excerpt: A reasonable case could be made that the scientific interest in catalytic oxidation was the basis for the recognition of the phenomenon of catalysis. Davy, in his attempt in 1817 to understand the science associated with the safety lamp he had invented a few years earlier, undertook a series of studies that led him to make the observation that a jet of gas, primarily methane, would cause a platinum wire to continue to glow even though the flame was extinguished and there was no visible flame. Dobereiner reported in 1823 the results of a similar investigation and observed that spongy platina would cause the ignition of a stream of hydrogen in air. Based on this observation Dobereiner invented the first lighter. His lighter employed hydrogen (generated from zinc and sulfuric acid) which passed over finely divided platinum and which ignited the gas. Thousands of these lighters were used over a number of years. Dobereiner refused to file a patent for his lighter, commenting that "I love science more than money." Davy thought the action of platinum was the result of heat while Dobereiner believed the ~ffect ~as a manifestation of electricity. Faraday became interested in the subject and published a paper on it in 1834; he concluded that the cause for this reaction was similar to other reactions.
Download or read book Partial Oxidation of Methane on Bismuth Molybdate Catalyst written by Arvind Sekhar and published by . This book was released on 1998 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Partial Oxidation of Methane and Ethane Over Metal Oxide Catalysts written by Dingjun Wang and published by . This book was released on 1995 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Partial Oxidation of Methane Over Noble Metal Catalysts written by Paul Mikael Torniainen and published by . This book was released on 1994 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Catalytic Partial Oxidation of Methane Over Nickel and Ruthenium Based Catalysts for GTL Applications written by and published by . This book was released on 2015 with total page 83 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Partial Oxidation of Methane to Formaldehyde Over Molybdenum Oxide based Catalysts written by Marianne Rose Smith and published by . This book was released on 1992 with total page 462 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Catalytic Methane Partial Oxidation Over Silica and Silica Supported Iron Phosphate written by Mohammad B. Al-Sahali and published by . This book was released on 2000 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Partial Oxidation of Methane Over Vanadia silica Cogel Catalysts written by Bunjerd Jongsomjit and published by . This book was released on 1998 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis Gas Formation by Partial Oxidation of Methane Over Metal Catalyst written by J. Nakamura and published by . This book was released on 1991 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Methane Conversion by Oxidative Processes written by Eduardo E. Wolf and published by Springer. This book was released on 1992 with total page 566 pages. Available in PDF, EPUB and Kindle. Book excerpt: A reasonable case could be made that the scientific interest in catalytic oxidation was the basis for the recognition of the phenomenon of catalysis. Davy, in his attempt in 1817 to understand the science associated with the safety lamp he had invented a few years earlier, undertook a series of studies that led him to make the observation that a jet of gas, primarily methane, would cause a platinum wire to continue to glow even though the flame was extinguished and there was no visible flame. Dobereiner reported in 1823 the results of a similar investigation and observed that spongy platina would cause the ignition of a stream of hydrogen in air. Based on this observation Dobereiner invented the first lighter. His lighter employed hydrogen (generated from zinc and sulfuric acid) which passed over finely divided platinum and which ignited the gas. Thousands of these lighters were used over a number of years. Dobereiner refused to file a patent for his lighter, commenting that "I love science more than money." Davy thought the action of platinum was the result of heat while Dobereiner believed the ~ffect ~as a manifestation of electricity. Faraday became interested in the subject and published a paper on it in 1834; he concluded that the cause for this reaction was similar to other reactions.
Download or read book Methane Oxidation Over Dual Redox Catalysts Final Report written by and published by . This book was released on 1992 with total page 135 pages. Available in PDF, EPUB and Kindle. Book excerpt: Catalytic oxidation of methane to partial oxidation products, primarily formaldehyde and C2 hydrocarbons, was found to be directed by the catalyst used. In this project, it was discovered that a moderate oxidative coupling catalyst for C2 hydrocarbons, zinc oxide, is modified by addition of small amounts of Cu and Fe dopants to yield fair yields of formaldehyde. A similar effect was observed with Cu/Sn/ZnO catalysts, and the presence of a redox Lewis acid, Fe{sup III} or Sn{sup IV}, was found to be essential for the selectivity switch from C2 coupling products to formaldehyde. The principle of double doping with an oxygen activator (Cu) and the redox Lewis acid (Fe, Sn) was pursued further by synthesizing and testing the CuFe-ZSM-5 zeolite catalyst. The Cu{sup II}(ion exchanged) Fe{sup III}(framework)-ZSM-5 also displayed activity for formaldehyde synthesis, with space time yields exceeding 100 g/h-kg catalyst. However, the selectivity was low and earlier claims in the literature of selective oxidation of methane to methanol over CuFe-ZSM-5 were not reproduced. A new active and selective catalytic system (M=Sb, Bi, Sn)/SrO/La2O3 has been discovered for potentially commercially attractive process for the conversion of methane to C2 hydrocarbons, (ii) a new principle has been demonstrated for selectivity switching from C2 hydrocarbon products to formaldehyde in methane oxidations over Cu, Fe-doped zinc oxide and ZSM-5, and (iii) a new approach has been initiated for using ultrafine metal dispersions for low temperature activation of methane for selective conversions. Item (iii) continues being supported by AMOCO while further developments related to items (i) and (ii) are the objective of our continued effort under the METC-AMOCO proposed joint program.
