Download or read book Partial Oxidation of Methanol on Molybdenum and Vanadium Oxide Catalysts written by Raúl Miranda and published by . This book was released on 1983 with total page 648 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Oxidation of Methanol Over Molybdenum vanadium Oxide Catalysts written by Mahendra Kumar Dosi and published by . This book was released on 1971 with total page 338 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Oxidation of Methanol Over Molybdenum vanadium Oxide Catalysts written by Mahendra Kumar Dosi and published by . This book was released on 1971 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Oxidation of Methanol Over Molybdenum vanadium Oxide Catalysts microform written by Dosi, Mahendra Kumar and published by National Library of Canada. This book was released on 1971 with total page 338 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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.
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 Study of Partial Oxidation of Methanol Over Finely Divided Molybdenum Oxide written by Jong Shik Chung and published by . This book was released on 1984 with total page 514 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Partial Oxidation of Methanol to Formaldehyde Over Mo Sn Oxide Catalysts written by Rowaida George Zoumot and published by . This book was released on 1992 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Methanol Oxidation on Molybdenum Oxide Catalysts written by Ibrahim Wawata and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 The Oxidation of Methanol with Air Over Oxide Catalysts written by Wesley Rasmus Peterson and published by . This book was released on 1929 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Third World Congress on Oxidation Catalysis written by S.T. Oyama and published by Elsevier. This book was released on 1997-09-12 with total page 1277 pages. Available in PDF, EPUB and Kindle. Book excerpt: The overall theme of the 3rd World Congress is "Atom Efficient Catalytic Oxidations for Global Technologies". This theme was chosen to stimulate the participants to report their findings with an emphasis on conserving valuable material in their catalytic transformations, as well as conserving energy, in an environmentally responsible manner. Progress towards this stated goal is substantial as evidenced by the tremendous response of the community in their participation of quality publications complied in these Proceedings of the Congress.The subjects presented span a wide range of oxidation reactions and catalysts. These include the currently important area of lower alkane oxidation to the corresponding olefins, unsaturated aldehydes, acids and nitriles.The four featured lectures and seven plenary lectures constitute the general background and overview of the subject matter at hand. The 104 contributed papers and 13 poster manuscripts, summarized in this compendium, probe new avenues to achieve catalytically efficient oxidation reactions for the future needs of mankind in a global environment.
Download or read book Aqueous Oxidation of Methanol by Vanadium Containing Biocatalysts and Biocatalyst Mimics written by Julie E. Molinari and published by . This book was released on 2012 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: Despite significant structural differences between the active sites of supported vanadium oxide catalysts such as supported VO4/SiO 2, and vanadium bromoperoxidase enzyme mimics such as the vanadium peroxo-oxo compound chelated with N-(2-hydroxyethyl)iminodiacetic acid (heida) or K[VO(O 2)(heida)], both catalysts are capable of conducting similar partial oxidation reactions. The K[VO(O2)(heida)](aq) vanadium enzyme mimic contains a vanadium peroxo-oxo structure, O=VO2, that is not present for vanadia supported on inorganic oxides such as silica. Vanadia dispersed on silica is present as a trigonal pyramidal surface VO4 species possessing one terminal V=O bond and three bridging V-O-Si bonds under dehydrated conditions. The first objective of the studies included in this dissertation was to compare the aqueous methanol oxidation mechanism of K[VO(O 2)(heida)](aq) with that of the vapor-solid methanol oxidation by supported VO4/SiO2. The second objective was then to extend this to the study of Vanadium Haloperoxidases (VHPOs), thereby beginning to bridge the gap between heterogeneous and enzyme catalysis. In this study, we have used in situ Raman, UV-vis and ATR-IR spectroscopy during methanol oxidation to examine the nature of the active sites, most abundant reaction intermediates, rate-determining-step, and oxidation mechanisms of the K[VO(O2)(heida)](aq) mimic compound and inorganic supported vanadia catalyst. In both catalytic systems, methanol chemisorbs at the bridging V-O-ligand and V-O-Si sites. The use of methanol as a molecular probe was employed to provide important information on the active site and mechanism of oxidation by K[VO(O2)(heida)](aq). This study elucidates the K[VO(O2)(heida)](aq) active site, most abundant reaction intermediates, the rate-determining-step, and the important role of the vanadium peroxo structure for aqueous methanol oxidation, bridging the gap between inorganic and protein based vanadate oxidation catalysts. These results were then used as a benchmark for the study of Vanadium Haloperoxidase enzymes.
Download or read book Nanostructured Catalysts written by Christian Hess and published by Royal Society of Chemistry. This book was released on 2011-07-22 with total page 453 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book gives a comprehensive up-to-date summary of the existing information on the structural/electronic properties, chemistry and catalytic properties of vanadium and molybdenum containing catalysts. It discusses the importance of nanoscience for the controlled synthesis of catalysts with functional properties and introduces the necessary background regarding surface properties and preparation techniques, leading from a textbook level to the current state of knowledge. Then follows an extensive survey and analysis of the existing open and patent literature - an essential knowledge source for the development of the new generation of partial oxidation catalysts. Important examples from current research on partial oxidation reactions are reviewed from experts in the field. The next chapter discusses the importance of 2- and 3-dimensional model systems for a fundamental understanding of the structure of transition metal oxide catalysts and its correlation to reactivity. Finally, an outlook on research opportunities within the area of partial oxidation reactions is presented.
Download or read book Oxidation of Methanol Over Molybdenum Oxide tungsten Oxide Catalyst written by Satyendra Kumar Jain and published by . This book was released on 1976 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Oxidation of Methanol Over Molybdenum Oxide tungsten Oxide Catalyst written by Jain, Satyendra Kumar and published by 1976.. This book was released on 1976 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt:
