Download or read book Raman Spectroscopic Studies of Iron molybdenum Oxide Catalysts for the Oxidation of Methanol to Formaldehyde written by James Harvey Wilson and published by . This book was released on 1986 with total page 366 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Raman Spectroscopic Studies of Iron molybdenum Oxide Catalysts for the Oxidation of Methanol to Formaldehyde written by James Harvey Wilson (III) and published by . This book was released on 1986 with total page 396 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Partial Oxidation of Methanol to Formaldehyde Over Molybdenum containing Catalysts written by Tsong-Jen Yang and published by . This book was released on 1982 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Laser Raman Spectroscopic Characterization of Mixed Tin antimony Oxide Catalysts and Supported Molybdenum Oxide Catalysts written by Sharon Rae Stampfl and published by . This book was released on 1986 with total page 438 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Electrochemical and Surface enhanced Raman Spectroscopic Studies of CO and Methanol Oxidation written by Yuqing Yang and published by . This book was released on 2008 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt: Molecular level information for carbon monoxide and methanol electrooxidation is provided by in situ surface-enhanced Raman spectroscopy (SERS) in this work for better understanding the mechanism of CO and methanol electrooxidation on transition metals. Electrooxidation of CO and methanol on transition metals are studied by cyclic voltammetry and in situ SERS. Thickness effect of overlayer metals on CO adsorption and oxidation activity is studied and explained by the strain effect and ligand effect. The cumulative effect for CO oxidation on Pd is the positive shift of CO oxidation peak position. Both the strain effect and ligand effect cause the negative shift of CO oxidation on Pt. Methanol electrooxidation on Ru is demonstrated by the C-O stretching band from COads on Ru oxide in SER spectra, which suggests that at higher potentials methanol oxidation on Ru sites needs to be taken into account in the catalytic mechanism of Pt-Ru catalysts in the direct methanol fuel cell.

Download or read book Partial Oxidation of Methanol to Formaldehyde Over Sb Mo Oxide Catalysts written by Rafael Alfredo Díaz Real and published by . This book was released on 1991 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The kinetics of the vapor phase air oxidation of methanol to formaldehyde over molybdenum oxide catalysts, antimony oxide catalyst, and their mixtures (both supported and unsupported), at atmospheric pressure and different operating conditions, have been studied in a fixed-bed integral reactor heated by a fluidized sand bath. The effect of various process variables, namely the process temperature (T), the ratio of catalysts to feed flow rate or space time (W/F), and the ratio of methanol fed to air (R), on conversion and yield have been determined. A screening study at varying operating conditions was performed to determine the optimum composition of a Sb$\sb2\rm O\sb4$-MoO$\sb3$ mixture. On the basis of this study a catalyst containing 67% $\rm Sb\sb2O\sb4$-33% MoO$\sb3$ was selected for the detailed kinetic study of oxidation of methanol to formaldehyde. The operating conditions studied were as follows: temperature in the range 623 to 698 K, space times from 5 to 50 $\rm g\sb{cat}/mol\sb{CH\sb3OH}h\sp{-1},$ and methanol to air ratios in the range 0.04 to 0.10 mol$\rm\sb{CH\sb3OH}h\sp{-1}/mol\sb{air}h\sp{-1}.$ This catalyst proved to be highly active and selective to formaldehyde formation. Yields up to $\sim$100% were obtained. Best operating conditions found were obtained at a space time of 27.5 for a methanol/air ratio of 0.06 and a temperature of 698 K. The rate equation for the oxidation of methanol to formaldehyde was derived on the basis of a two-stage redox mechanism$$\eqalign{\rm CH\sb3OH\sb{(g)} + S\sb{ox}\ {\buildrel{k\sb1}\over{\to}}\ &\rm HCHO\sb{(g)} + H\sb2O\sb{(g)} + S\sb{red}\cr\rm O\sb{2\sb{(g)}} + &\rm S\sb{red}\ {\buildrel{k\sb2}\over{\to}}\ S\sb{ox}\cr}$$where S$\rm\sb{ox}$ represents an active site of lattice oxygen and S$\rm\sb{red}$ represents a reduced site of lattice oxygen. The rate equation for the temperature of 648 to 698 K which correlated the data was$$\rm r = {k\sb1P\sb{M}\over 1+{k\sb1P\sb{M}\over 2k\sb2P\sb{O\sb2}}}$$where k$\sb1$ and k$\sb2$ are the temperature dependent rate constants of steps one and two. The equations relating k$\sb1$ and k$\sb2$ with temperature were$$\eqalign{&\rm ln\ k\sb1 = -6.4039-{6.9153\times10\sp3\over T}\cr&\rm ln\ k\sb2 = -3.0154 + {1.8809\times10\sp3\over T}\cr}$$ Several spectroscopic and analytical techniques, viz, electron spin resonance (ESR), x-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM), and adsorption studies were used to characterize the catalysts. The surface are of the catalyst used in the kinetic study was 6.1 m$\sp2$/g as determined by the BET method. A preliminary study of the Sb-Mo oxide mixture (load of $\sim$5 wt%) supported on Y zeolite was also carried out. Maximum yield obtained was comparable to that obtained with pure MoO$\sb3.$ A new catalyst has been developed that gave nearly 100% conversion and 100% yield. The industrial potential of this catalyst is very promising.

Download or read book Dissertation Abstracts International written by and published by . This book was released on 1987 with total page 468 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Methanol Oxidation on Transition Elements Oxides written by Abdulmohsen Alshehri and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Methanol oxidation to formaldehyde is one of the most important industries in our lives; the reaction occurs on catalyst surface in heterogeneous catalysis. Iron molybdate is the current selective catalyst. However, molybdenum volatilises during methanol oxidation and leaving the catalyst with a low molybdenum ratio, which deactivates the catalyst, a 2.2 Mo: 1Fe iron molybdate catalyst was used instead the stoichiometric catalyst, while yield of formaldehyde cannot be 100%. The goal of this study is to find more selective and more productive catalyst than iron molybdate catalyst, the first step is to find another transition element as selective as molybdenum, because molybdenum is the selective part, and iron is the active part, the resulting iron molybdate catalyst is a selective catalyst to formaldehyde near molybdenum and active near iron. Experimentally, catalysts were prepared using co-precipitation method, however, some doped catalysts were papered by incipient wetness impregnation, also sol-immobilization was used to prepare nano-gold particles on the surfaces of few supports. Catalysts characterizations were carried out within several techniques for the surface analysis (XPS) and bulk analysis (XRD), also the surface area was measured by BET equipment. Raman too was used in this study, while micro-reactor was the reactor to determine selectivity and activity of each catalyst. When molybdenum replaced by vanadium, the catalyst yielded 100% formaldehyde at 200 oC; moreover, tungsten was selective. Likewise, iron was replaced by other active metals such as manganese, copper and bismuth, which are active. Nano-gold improved activity when doped on molybdenum oxide and iron molybdate supports.

Download or read book Handbook of Raman Spectroscopy written by Ian R. Lewis and published by CRC Press. This book was released on 2001-08-08 with total page 1076 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work covers principles of Raman theory, analysis, instrumentation, and measurement, specifying up-to-the-minute benefits of Raman spectroscopy in a variety of industrial and academic fields, and how to cultivate growth in new disciplines. It contains case studies that illustrate current techniques in data extraction and analysis, as well as over 500 drawings and photographs that clarify and reinforce critical text material. The authors discuss Raman spectra of gases; Raman spectroscopy applied to crystals, applications to gemology, in vivo Raman spectroscopy, applications in forensic science, and collectivity of vibrational modes, among many other topics.

Download or read book In situ Characterization of Heterogeneous Catalysts written by José A. Rodriguez and published by John Wiley & Sons. This book was released on 2013-04-17 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt: Helps researchers develop new catalysts for sustainable fueland chemical production Reviewing the latest developments in the field, this bookexplores the in-situ characterization of heterogeneous catalysts,enabling readers to take full advantage of the sophisticatedtechniques used to study heterogeneous catalysts and reactionmechanisms. In using these techniques, readers can learn to improvethe selectivity and the performance of catalysts and how to preparecatalysts as efficiently as possible, with minimum waste. In-situ Characterization of Heterogeneous Catalysts featurescontributions from leading experts in the field of catalysis. Itbegins with an introduction to the fundamentals and thencovers: Characterization of electronic and structural properties ofcatalysts using X-ray absorption fine structure spectroscopy Techniques for structural characterization based on X-raydiffraction, neutron scattering, and pair distribution functionanalysis Microscopy and morphological studies Techniques for studying the interaction of adsorbates withcatalyst surfaces, including infrared spectroscopy, Ramanspectroscopy, EPR, and moderate pressure XPS Integration of techniques that provide information on thestructural properties of catalysts with techniques that facilitatethe study of surface reactions Throughout the book, detailed examples illustrate how techniquesfor studying catalysts and reaction mechanisms can be applied tosolve a broad range of problems in heterogeneous catalysis.Detailed figures help readers better understand how and why thetechniques discussed in the book work. At the end of each chapter,an extensive set of references leads to the primary literature inthe field. By explaining step by step modern techniques for the in-situcharacterization of heterogeneous catalysts, this book enableschemical scientists and engineers to better understand catalystbehavior and design new catalysts for green, sustainable fuel andchemical production.

Download or read book In Situ Resonance Raman Studies of Molybdenum Oxide Based Selective Oxidation Catalysts written by and published by . This book was released on 2001 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book In situ resonance raman studies of molybdenum oxide based selective oxidation catalysts written by Martin Dieterle and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Index to American Doctoral Dissertations written by and published by . This book was released on 1986 with total page 606 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Origin of the Ligand Effect in Supported and Bulk Metal Oxide Catalysis written by Loyd James Burcham and published by . This book was released on 1999 with total page 624 pages. Available in PDF, EPUB and Kindle. Book excerpt: The strong influence of the oxide support upon the turn-over frequency (TOF) of methanol oxidation over supported metal oxide catalysts has been well documented in recent years, but has not yet been completely understood at a fundamental level. The present dissertation probes the mechanistic origin of this interesting phenomenon (e.g., adsorption equilibrium of methanol to surface methoxy species, rate-determining methoxy surface decomposition, and product desorption equilibrium) and also extends the investigation to include similar ligand effects in bulk metal oxide catalysts. Qualitative in situ Raman, IR, and UV-Vis DRS spectroscopy of supported vanadia catalysts during steady-state methanol oxidation demonstrated that the molecular structures of surface vanadia species are very sensitive to the coordination and H-bonding effects of the adsorbed surface methoxy species (the reactive surface intermediates). Hence, spectroscopic monitoring of the surface methoxy intermediates, instead of the surface metal oxide species, provides more reliable information about the surface reaction kinetics responsible for ligand effects in methanol oxidation.

Download or read book Energy Research Abstracts written by and published by . This book was released on 1978 with total page 1372 pages. Available in PDF, EPUB and Kindle. Book excerpt: Semiannual, with semiannual and annual indexes. References to all scientific and technical literature coming from DOE, its laboratories, energy centers, and contractors. Includes all works deriving from DOE, other related government-sponsored information, and foreign nonnuclear information. Arranged under 39 categories, e.g., Biomedical sciences, basic studies; Biomedical sciences, applied studies; Health and safety; and Fusion energy. Entry gives bibliographical information and abstract. Corporate, author, subject, report number indexes.

Download or read book Partial Oxidation of Methanol to Formaldehyde Over Molybdenum tin Oxide Catalysts written by Rowaida George Zoumot and published by . This book was released on 1992 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The vapor phase air oxidation of methanol to formaldehyde was investigated over molybdenum oxide, tin oxide and their mixtures in an integral flow reactor at atmospheric pressure between temperature of 513 and 573 K, a space time of 10-40 hr g-cat/g-mol methanol and a molar ratio of 0.04-0.1 mol CH3OH/mol air. Experiments were done under such conditions that the effects of internal and external heat and mass transfer effects were negligible. The effects of several process variables, temperature, space time and methanol/air ratio on the conversion of methanol and the selectivity of the catalyst for formaldehyde production were determined. The results indicated that the impact of the process variables on the conversion, selectivity and yield of formaldehyde were in the following decreasing order T > W/F > R. A screening study indicated the optimum catalyst composition to be 50% SnO2 and 50% MoO3, while conversion increased with temperature and W/F selectivity decreased. This catalyst proved to be highly active and selective to formaldehyde production. Selectivity and yield of up to about 100% were obtained at 100% conversion at a temperature of 553 K, a space time (W/F) of 40 g-cat/g-mol methanol per hour and a molar ratio (R) of 0.04 mol CH3 OH/mol air. The rate expression r=k1P2M 1+k1P2M2k 2PO2 was deduced assuming a steady-state involving two-stage irreversible oxidation-reduction process. It represented the experimental data satisfactorily. Arrhenius plots of the two rate constants gave activation energies of 31.7 and 18.1 kcal/g-mol.