Dissertations / Theses: 'Methanol'

1

Squire, Gavin Daniel. "Partial oxidation of methane to methanol and formaldehyde." Thesis, University of Reading, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.278072.

Full text

APA, Harvard, Vancouver, ISO, and other styles

2

Chellappa, Anand S. "Methane conversion to methanol : homogeneous and catalytic studies /." free to MU campus, to others for purchase, 1997. http://wwwlib.umi.com/cr/mo/fullcit?p9842517.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Matthews, Terry. "The Partial Oxidation of Methane to Methanol & Formaldehyde." TopSCHOLAR®, 1987. https://digitalcommons.wku.edu/theses/2602.

Full text

Abstract:

The conversion of methane into methanol is viewed as one approach to utilizing the vast reserves of natural gas. One such prospect for the utilization of natural gas is the partial oxidation of methane to methanol. Methanol ranks high on the commodity market. As a liquid it is easily transportable and therefore skirts the issue of vast amounts of a gas having to be transported either by pipeline or by liquifying. The catalytic partial oxidation of methane to methanol is investigated. Two different reactor systems are employed. The first system is a fixed bed system. The second is a fluid bed system. Areas to be addressed are different catalyst systems, different loading rates, elemental promotion, different supports, surface area, catalyst particle mesh size, and effects of preparation.

APA, Harvard, Vancouver, ISO, and other styles

4

Afonso, Joana da Costa Franco. "Catalytic hydrogenation of carbon dioxide to form methanol and methane." Master's thesis, Faculdade de Ciências e Tecnologia, 2013. http://hdl.handle.net/10362/10854.

Full text

APA, Harvard, Vancouver, ISO, and other styles

5

Olsson, Susanna. "Dynamics of a spin-forbidden reaction transforming methane to methanol." Thesis, Uppsala universitet, Institutionen för kemi - BMC, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-385895.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Prince, Bruce M. "The Mechanisms of Methane C–H Activation and Oxy-insertion Via Small Transition Metal Complexes: a DFT Computational Investigation." Thesis, University of North Texas, 2014. https://digital.library.unt.edu/ark:/67531/metadc500116/.

Full text

Abstract:

Our country continues to demand clean renewable energy to meet the growing energy needs of our time. Thus, natural gas, which is 87% by volume of methane, has become a hot topic of discussion because it is a clean burning fuel. However, the transportation of methane is not easy because it is a gas at standard temperature and pressure. The usage of transition metals for the conversion of small organic species like methane into a liquid has been a longstanding practice in stoichiometric chemistry. Nonetheless, the current two-step process takes place at a high temperature and pressure for the conversion of methane and steam to methanol via CO + H2 (syngas). The direct oxidation of methane (CH4) into methanol (CH3OH) via homogeneous catalysis is of interest if the system can operate at standard pressure and a temperature less than 250 C. Methane is an inert gas due to the high C-H bond dissociation energy (BDE) of 105 kcal/mol. This dissertation discusses a series of computational investigations of oxy-insertion pathways to understand the essential chemistry behind the functionalization of methane via the use of homogeneous transition metal catalysis. The methane to methanol (MTM) catalytic cycle is made up of two key steps: (1) C-H activation by a metal-methoxy complex, (2) the insertion of oxygen into the metal−methyl bond (oxy-insertion). While, the first step (C-H activation) has been well studied, the second step has been less studied. Thus, this dissertation focuses on oxy-insertion via a two-step mechanism, oxygen-atom transfer (OAT) and methyl migration, utilizing transition metal complexes known to activate small organic species (e.g., PtII and PdII complexes). This research seeks to guide experimental investigations, and probe the role that metal charge and coordination number play.

APA, Harvard, Vancouver, ISO, and other styles

7

Waller, David. "Methanol synthesis catalysts." Thesis, University of Bath, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.495621.

Full text

Abstract:

The commercial synthesis of methanol from C02, CO and H2 is achieved using copper-zinc oxide catalysts based on the low pressure process developed by I. C. I. Copper-zinc oxide based catalysts are generally prepared by the coprecipitation of a hydroxide, hydroxycarbonate or hydroxynitrate precursor followed by calcination and reduction. Ye have investigated how the structure and composition of precursor phases affects the dispersion of CuO and ZnO in the calcined catalysts and Cu in the reduced catalysts. Parameters which control precursor formation, including the method of mixing the reagents, pH, Cu/Zn ratio and the presence or absence of aluminium and precursor ageing were studied. Precursor phases which contain all the catalyst components give rise to highly dispersed copper and zinc oxide after reduction. Zincian-malachite (Cuz-xZnx(OH)2CO3) gives rise to higher copper dispersion than aurichalcite (Cus-xZnx(OH)e(CO3)2) although both contain copper and zinc. This is because the malachite precipitate has a much smaller particle size than aurichalcite which, together with a homogeneous composition hinders growth of CuO and ZnO during calcination giving rise to a high dispersion. The activity of the reduced catalysts towards methanol synthesis and the reverse water-gas shift reaction were determined and the results support the proposal that the active site for these reactions is located on the metallic copper surface.

APA, Harvard, Vancouver, ISO, and other styles

8

Hammond, Charles Rhodri. "Partial oxidation of methane to methanol using modified mixed metal oxides." Thesis, Cardiff University, 2004. http://orca.cf.ac.uk/54537/.

Full text

Abstract:

The current steam reforming process for the production of CH₃OH is complicated and difficult, and therefore the direct partial oxidation of CH₄ to CH₃OH would be economically desirable. In previous work a design approach for a selective partial oxidation catalyst has been investigated, which comprises the combination of components with a desired reactivity, producing a successful selective partial oxidation catalyst. In this approach, it is considered a successful partial oxidation catalyst must activate methane, activate oxygen and not destroy the desired product, methanol. All these properties could not be found in a single catalyst, so it was proposed that two synergistic components could be combined, one responsible for methane activation and the other for oxygen activation/insertion. Previous work has studied the CH₄/D₂ exchange reaction as an indication of the ability of a metal oxide surface to activate CH₄. Two metal oxides demonstrated appreciable activity for the activation of CH₄, these being Ga₂C₃ and ZnO. These oxides were then doped with different metals in order to try and increase the activity of the catalyst. The doping of Ga₂O₃ with Zn or Mg did not improve the methane oxidation properties of Ga₂C₃, and the doping of ZnO with Ga significantly lowered the light off temperature, the temperature at which CH₄ was first detected, and increased its oxidative capacity. The addition of precious metals significantly affected the catalysts ability to activate CH₄. The addition of Au to the Ga and Zn catalysts dramatically reduced the light off temperature, and increased its rate of oxidation at lower temperatures, with the optimum loading 2% for both catalysts. For GaO(OH) and ZnO, the addition of 1%Au and l%Pt by coprecipitation produced a synergistic effect, producing lower light offs and higher CH₄ conversion than the singly doped catalysts with Au and Pt separately. When the methane activation catalysts were combined with MoO₃ in a physical mixture, a number of the mixtures produced higher methanol per pass percentage yields than its constituent parts. It is concluded that the increased methane activation properties beneficially interact with the oxygen activation and insertion properties of MoO₃. However, none of the yields reported were significantly higher. A dual bed system, with the lower layer comprising the methane activation catalysts, and the upper layer consisting of MoO₃ was tested. The results for this system were promising, with the low temperature activation of CH₄, combined with the oxygen insertion ability of MoO₃, producing high selectivities of CH₃OH at much lower temperatures. The best results were obtained when the ratio of the two layers was 50:50 with respect to 2%Au ZnO and MoO₃. In previous work a design approach for a selective partial oxidation catalyst has been investigated, by combining components with a desired reactivity to produce a successful selective partial oxidation catalyst, which must activate methane and oxygen, and not destroy methanol. All these properties could not be found in a single catalyst, so it was proposed that two synergistic components could be combined, one responsible for methane activation and the other for oxygen activation/insertion. The doping of ZnO with Ga significantly lowered the light off temperature, and increased its oxidative capacity, an effect which was not seen with the doping of Ga₂O₃ with Zn or Mg. The addition of Au to the Ga and Zn catalysts dramatically reduced the light off temperature, and increased its rate of oxidation at lower temperatures, both with optimum loading of 2%. The addition of l%Au and l%Pt produced a synergistic effect, producing lower light offs and higher CH₄ conversion than the singly doped catalysts with Au and Pt separately. When the methane activation catalysts were combined with MoO₃ in a physical mixture, a number of the mixtures produced higher methanol per pass percentage yields than its constituent parts. It is concluded that the increased methane activation properties beneficially interact with the oxygen activation and insertion properties of MoO₃. The dual bed system, with the lower layer comprising the methane activation catalysts, and the upper layer consisting of MoO₃ produced promising results, with the low temperature activation of CH₄, combined with the oxygen insertion ability of MoO₃, producing high selectivities of CH₃OH at much lower temperatures. The best results were obtained when the ratio of the two layers was 50:50 with respect to 2%Au ZnO and MoO₃. (Abstract shortened by UMI.).

APA, Harvard, Vancouver, ISO, and other styles

9

Krämer, Alexander. "Heterogen katalysierte Partialoxidationen in überkritischem Wasser die selektive Oxidation von Methanol, Methan und Propen an Kupfer und Kupferlegierungen /." [S.l. : s.n.], 2001. http://elib.tu-darmstadt.de/diss/000107/kraemer.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Bröll, Dirk. "Partialoxidationen in überkritischem Wasser mit molekularem Sauerstoff die Reaktionen von Methanol, Methan und Propylen mit und ohne Silberkatalysatoren /." [S.l. : s.n.], 2001. http://elib.tu-darmstadt.de/diss/000118/.

Full text

APA, Harvard, Vancouver, ISO, and other styles

11

Modibedi, Remegia Mmalewane. "The catalytic membrane reactor for the conversion of methane to methanol and formaldehyde under mild conditions." Thesis, University of the Western Cape, 2005. http://etd.uwc.ac.za/index.php?module=etd&amp.

Full text

Abstract:

This thesis described the development of new catalytic system for the conversion of natural gas (methane) to liquid products such as methanol and formaldehyde. This technology can allow the exploitation of small and medium size gas fields without the need to build an expensive gas to liquid plants or long pipelines. The technology is based on a concept of non-separating membrane reactor where an inorganic membrane paper serves as a catalyst support through which a reaction mixture is flowing under mild conditions and short residence times.

APA, Harvard, Vancouver, ISO, and other styles

12

Narsimhan, Karthik. "Catalytic, low temperature oxidation of methane into methanol over copper-exchanged zeolites." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/109671.

Full text

Abstract:

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Chemical Engineering, 2017.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 135-147).
As production of shale gas has increased greatly in the United States, the amount of stranded shale gas that is flared as carbon dioxide has become significant enough to be considered an environmental hazard and a wasted resource. The conversion of methane, the primary component of natural gas, into methanol, an easily stored liquid, is of practical interest. However, shale wells are generally inaccessible to reforming facilities, and construction of on-site, conventional methanol synthesis plants is cost prohibitive. Capital costs could be reduced by the direct conversion of methane into methanol at low temperature. Existing strategies for the partial oxidation of methane require harsh solvents, need exotic oxidizing agents, or deactivate easily. Copper-exchanged zeolites have emerged as candidates for methanol production due to high methanol selectivity (> 99%), utilization of oxygen, and low reaction temperature (423-473 K). Despite these advantages, three significant shortcomings exist: 1) the location of surface intermediates on the zeolite is not well understood; 2) methane oxidation is stoichiometric, not catalytic; 3) there are few active sites and methanol yield is low. This work addresses all three shortcomings. First, a new reaction pathway is identified for methane oxidation in copper-exchanged mordenite zeolites using tandem methane oxidation and Koch carbonylation reactions. Methoxy species migrate away from the copper active sites and adsorb onto Bronsted acid sites, signifying spillover on the zeolite surface. Second, a process is developed as the first instance of the catalytic oxidation of methane into methanol at low temperature, in the vapor phase, and using oxygen as the oxidant. A variety of commercially available copper-exchanged zeolites are shown to exhibit stable methanol production with high methanol selectivity. Third, catalytic methanol production rates and methane conversion are further improved 100- fold through the synthetic control of copper speciation in chabazite zeolites. Isolated monocopper species, directed through the one-pot synthesis of copper-exchanged chabazite zeolites, correlates with methane oxidation activity and is likely the precursor to the catalytic site. Together, these synthetic methods provide guidelines for catalyst design and further improvements in catalytic activity.
by Karthik Narsimhan.
Ph. D.

APA, Harvard, Vancouver, ISO, and other styles

13

Sultan, Jassim. "Direct methanol fuel cells /." Internet access available to MUN users only, 2003. http://collections.mun.ca/u?/theses,162066.

Full text

APA, Harvard, Vancouver, ISO, and other styles

14

Weeks, Simon A. "Anodes for methanol oxidation." Thesis, University of Oxford, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.258023.

Full text

APA, Harvard, Vancouver, ISO, and other styles

15

Xu, Chao. "Transport phenomena of methanol and water in liquid feed direct methanol fuel cells /." View abstract or full-text, 2008. http://library.ust.hk/cgi/db/thesis.pl?MECH%202008%20XU.

Full text

APA, Harvard, Vancouver, ISO, and other styles

16

Günter, Marco Maria. "Structure and activity of copper-zinc oxide catalysts studied using X-ray diffraction and absorption spectroscopy." [S.l.] : [s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=962998508.

Full text

APA, Harvard, Vancouver, ISO, and other styles

17

Taylor, Stuart Hamilton. "The design of new catalysts for the partial oxidation of methane to methanol." Thesis, University of Liverpool, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260339.

Full text

Abstract:

The direct partial oxidation of CH4 to CH30H would offer considerable economic advantages over the current two stage process. It would also facilitate the utilisation of natural gas reserves in remote locations. To date, the catalytic partial oxidation of CH4 to CH30H has been extensively studied, however, it has proved to be an extremely demanding reaction which has met with little success. This study has adopted a design approach for the identification of new catalysts by considering the efficacy of single oxides for CH4 activation, CH30H oxidation and 02 isotope exchange activity. On the basis of CH30H stability Sb203 was the best oxide, showing only 3 % CH30H conversion at 500°C. The majority of oxides totally combusted CH30H below 400°C. Mo03, Nb20S, Ta20S and W03 showed high selectivity to HCHO and (CH3hO with low levels of COx throughout the range of conversion. These oxides were not considered unsuitable from the perspective of CH30H stability as the products HCHO and (CH3hO are not considered undesirable by products from a CH4 partial oxidation process. A weak but significant correlation was observed between the combustion activity of the oxides and the oxygen exchange rate. Using CH4/D2 exchange as an indication of CH4 activation it has been shown that Ga203 was a particularly good catalyst, followed by ZnO and Cr203. A relationship between exchange activity and oxide basicity was established for the rare earth sesquioxides, MgO and CaO. This relationship indicak:d that CH4 activation took place by H+ abstraction to form a surface CH3- species. From these results and literature studies of oxygen isotope exchange, dual component oxides have been formulated as catalysts for CH4 partial oxidation. The best catalysts was Ga203/Mo03, prepared by a physical mixing process. This catalyst showed an increased yield of CH30H over the homogeneous gas phase oxidation of CH4 in a quartz chips packed reactor. This increased yield has been attributed to the development of a cooperative effect between the two component oxides. Comparison of the catalytic data with the homogeneous reaction in the empty reactor tube showed that the presence of a catalyst had a detrimental effect on the CH30H yield.

APA, Harvard, Vancouver, ISO, and other styles

18

Joseph, Krishna Sathyamurthy. "Hybrid direct methanol fuel cells." Thesis, Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/44777.

Full text

Abstract:

A new type of fuel cell that combines the advantages of a proton exchange membrane fuel cells and anion exchange membrane fuel cells operated with methanol is demonstrated. Two configurations: one with a high pH anode and low pH cathode (anode hybrid fuel cell (AHFC)),and another with a high pH cathode and a low pH anode (cathode hybrid fuel cell (CHFC)) have been studied in this work. The principle of operation of the hybrid fuel cells were explained. The two different hybrid cell configurations were used in order to study the effect of the electrode fabrication on fuel cell performance. Further, the ionomer content and properties such as the ion exchange capacity and molecular weight were optimized for the best performance. A comparison of the different ionomers with similar properties is carried out in order to obtain the best possible ionomer for the fuel cell. An initial voltage drop was observed at low current density in the AHFC, this was attributed to the alkaline anode and the effect of the ionomers with the new cationic groups were studied on this voltage drop was studied. These ionomers with the different cationic groups were studied in the CHFC design as well. Finally, the use of non platinum catalyst cathode with the CHFC design was also demonstrated for the first time.

APA, Harvard, Vancouver, ISO, and other styles

19

Plant, David F., Guillaume Maurin, and Robert G. Bell. "Diffusion of methanol in zeolites." Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-195554.

Full text

APA, Harvard, Vancouver, ISO, and other styles

20

Richardson, Ian William. "The biosynthesis of methanol dehydrogenase." Thesis, University of Southampton, 1992. https://eprints.soton.ac.uk/365535/.

Full text

APA, Harvard, Vancouver, ISO, and other styles

21

Yates, Andrew David Bennett. "Abnormal combustion - methanol versus gasoline." Doctoral thesis, University of Cape Town, 1988. http://hdl.handle.net/11427/8386.

Full text

Abstract:

Includes bibliographical references.
The maximum efficiency of conventional gasoline engines is largely determined by the compression ratio, and this is limited by the onset of kno8k. The maximum cylinder size is similarly constrained. The relatively higher knock resistance of methanol opens up possibilities for increased efficiency or engine size. The auto-ignition of methanol and gasoline was characterised in terms of fundamental parameters and the results were compared. The research findings were used in the analysis of a particular combustion chamber design to assess the potential of using squish as a means of avoiding knock in a large, spark-ignition methanol engine.

APA, Harvard, Vancouver, ISO, and other styles

22

Husman, S. H., W. B. McCloskey, and W. T. Molin. "Methanol Effect on Upland Cotton." College of Agriculture, University of Arizona (Tucson, AZ), 1994. http://hdl.handle.net/10150/209602.

Full text

Abstract:

The effects of foliar applied methanol on Upland cotton were measured in a large field study in Phoenix, AZ. An untreated check was compared to weekly applications of 30% methanol, 30% methanol plus 1% Urea and 0.1 % Fe EDTA, and 1% Urea and 0.1% Fe EDTA. Plant growth and development, photosynthesis, transpiration, soil water use and lint yields were measured. There were no differences in any of the measured variables between treatments.

APA, Harvard, Vancouver, ISO, and other styles

23

Lappas, Ingo. "Heterogene Katalyse in überkritischen Medien Charakterisierung von Metall- und Legierungskatalysatoren /." [S.l. : s.n.], 2001. http://elib.tu-darmstadt.de/diss/000179.

Full text

APA, Harvard, Vancouver, ISO, and other styles

24

Dawson, Craig. "Materials for direct methanol fuel cells: inhibition of methanol crossover using novel membrane electrode assemblies." Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/materials-for-direct-methanol-fuel-cells-inhibition-of-methanol-crossover-using-novel-membrane-electrode-assemblies(843284c4-3620-4cac-9118-06671d7bb420).html.

Full text

Abstract:

This thesis focuses on developing an alternative system for membrane electrode assembly (MEA) formation to use with a direct methanol fuel cell (DMFC). The approach involves incorporating inorganic fillers with an industry standard Nafion polymer as part of a methanol resistant composite barrier layer at the anode/membrane interface of MEA featuring Nafion 117 membranes. This procedure is used to reduce the fuel cell losses related to the crossover of un-oxidised methanol through the membrane and prevent its subsequent reaction at the cathode. The inorganic filler used within this study was mordenite that has Si/Al ratio of 5 and by incorporating this into the barrier layer a superior DMFC performance has been achieved in comparison to a standard MEA featuring a Nafion 117 membrane. The voltage, current density and power density used as a measure of DMFC performance under a range of methanol molarities (1M-4M) and cell temperatures (40°C-70°C) have been taken for both the novel and standard MEA. Linear sweep voltammetry (LSV) and AC impedance spectroscopy (ACIS) were used to give some insight into what was occurring within the MEA with regards to methanol crossover current and the proton conductivity within the DMFC. To obtain the best possible DMFC performance a range of mordenite loadings from 0wt%1.0wt% were utilised and an optimum loading of 0.5wt% was reached. MEA which featured mordenite that had undergone ion exchange into a protonated form (from the sodium form) and had a silane functional group (glycidoxypropyltrimethoxysilane) grafted onto the surface, gave DMFC performances that were as much as 50% better than the standard. The highest power density obtained with this MEA was 43.6mW/cm-2 compared to the 35mW/cm-2 obtained using the standard. Values obtained for the methanol crossover current and proton conductivity under working DMFC operating conditions showed that this novel MEA had as much as 16% lower methanol permeability compared to the standard combined with comparable proton conductivity when using a 1M methanol feed. The durability of a novel MEA featuring the 0.5wt% functionalised H-mordenite composite barrier layer was tested in the DMFC and compared to a standard MEA at a constant current of 50mA/cm-2 over 100 hours. The cell potential fell by 0.1mV/h in comparison to a 0.23mV/h loss observed with the standard. The work reported within this study aims to show that by incorporating a thin Nafion/mordenite composite layer at the anode/membrane interface within an MEA will result in improvements in DMFC performance. The development of this technology has led to the application for a patent due to the potential for the commercial development of DMFC using this novel approach.

APA, Harvard, Vancouver, ISO, and other styles

25

Storch, Henrik von Verfasser], Bernhard [Akademischer Betreuer] Hoffschmidt, and André [Akademischer Betreuer] [Bardow. "Methanol production via solar reforming of methane / Henrik von Storch ; Bernhard Hoffschmidt, André Bardow." Aachen : Universitätsbibliothek der RWTH Aachen, 2016. http://d-nb.info/1126040878/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

26

Thorn, Garrick J. S. "Development of an Immobilized Nitrosomonas europaea Bioreactor for the Production of Methanol from Methane." Thesis, University of Canterbury. Chemical and Process Engineering, 2006. http://hdl.handle.net/10092/1867.

Full text

Abstract:

This research investigates a novel approach to methanol production from methane. The high use of fossil fuels in New Zealand and around the world causes global warming. Using clearer, renewable fuels the problem could potentially be reduced. Biomass energy is energy stored in organic matter such as plants and animals and is one of the options for a cleaner, renewable energy source. A common biofuel is methane that is produced by anaerobic digestion. Although methane is a good fuel, the energy is more accessible if it is converted to methanol. While technology exists to produce methanol from methane, these processes are thermo-chemical and require large scale production to be economic. Nitrosomonas europaea, a nitrifying bacterium, has been shown to oxidize methane to methanol (Hyman and Wood 1983). This research investigates the possibility of converting methane into methanol using immobilized N. europaea for use in smaller applications. A trickle bed bioreactor was developed, containing a pure culture of N. europaea immobilized in a biofilm on ceramic raschig rings. The reactor had a biomass concentration of 7.82 ± 0.43 g VSS/l. This was between 4 – 15 times higher than other systems aimed at biologically producing methanol. However, the immobilization dramatically affected the methanol production ability of the cells. Methanol was shown to be produced by the immobilized cells with a maximum production activity of 0.12 ± 0.08 mmol/gVSS.hr. This activity was much lower than the typical reported value of 1.0 mmol/g dry weight.hr (Hyman and Wood 1983). The maximum methanol concentration achieved in this system was 0.129 ± 0.102 mM, significantly lower than previous reported values, ranging between 0.6 mM and 2 mM (Chapman, Gostomski, and Thiele 2004). The results also showed that the addition of methane had an effect on the energy gaining metabolism (ammonia oxidation) of the bacteria, reducing the ammonia oxidation capacity by up to 70%. It was concluded, because of the low methanol production activity and the low methanol concentrations produced, that this system was not suitable for a methanol biosynthesis process.

APA, Harvard, Vancouver, ISO, and other styles

27

Fratesi, Guido. "Low temperature methane-to-methanol conversion on transition metal surfaces. An ab initio study." Doctoral thesis, SISSA, 2005. http://hdl.handle.net/20.500.11767/4087.

Full text

APA, Harvard, Vancouver, ISO, and other styles

28

Guan, Xiangguo. "The photochemistry of polyhalomethanes in water and the water-catalyzed dehalogenation reactions of selected isopolyhalomethanes, halogenated methanols and halogenated formaldehydes." Click to view the E-thesis via HKUTO, 2006. http://sunzi.lib.hku.hk/hkuto/record/B38718960.

Full text

APA, Harvard, Vancouver, ISO, and other styles

29

Guan, Xiangguo, and 官向國. "The photochemistry of polyhalomethanes in water and the water-catalyzed dehalogenation reactions of selected isopolyhalomethanes,halogenated methanols and halogenated formaldehydes." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2006. http://hub.hku.hk/bib/B38718960.

Full text

APA, Harvard, Vancouver, ISO, and other styles

30

SOLASTIOUK, GALIVEL FRANCINE. "Equilibres liquide-vapeur des systemes propane-methanol et propane-methanol-dioxyde de carbone : mesures et representations." Paris, ENMP, 1988. http://www.theses.fr/1988ENMP0103.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

Chailuecha, Chatkaew. "Methanol barrier layers : modified membrane electrode assemblies for the improvement of direct methanol fuel cell performance." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/methanol-barrier-layer(2c347cde-c81d-4024-90b0-a62e1bf94918).html.

Full text

Abstract:

The direct methanol fuel cell (DMFC) performance has been improved via two approaches. The first approach reduces methanol crossover in the membrane electrode assemblies (MEAs) by incorporating a methanol barrier layer onto an anode electrode of the MEA. The second approach increases the triple phase boundaries via the modified morphology of catalyst layers in the MEA. Methanol barrier layers containing a composite layer of Nafion/mordenite (MOR), Nafion/zeolite Y (ZY), Nafion/montmorillonite (MMT) or Nafion/titanate (TN) were distributed onto the anode of an MEA. The performance of these MEAs were tested in a single cell DMFC for temperatures between 30-80 °C and methanol concentrations of 1 M-4 M and compared with a standard MEA to identify changes in power output. At 2 M methanol concentration and 80 °C, the MEAs featuring with Nafion/0.50 wt% MMT and Nafion/0.50 wt% TN delivered higher power densities, 19.76% and 26.60%, respectively, than that of standard MEA. The catalyst morphology has been adjusted by the dilution of catalyst ink to prevent an agglomeration of catalyst particles, resulting in the increased triple phase boundaries which are the phases for electrochemical reactions and for the transportation of electron and proton products. The new-standard MEA presented the best improvement in power density of 81.15% over the conventional counterpart at 80 °C and 2 M methanol concentration. This modified procedure was further utilised for MEAs fabrication. Further investigation has been carried out by the selected Nafion/MMT layer. The MMT loading of 0.25 wt%-1.00 wt% were incorporated onto the barrier layer where the Nafion/0.25 wt% MMT layer illustrated the best performance. This MEA attributed the highest power density of 69.14 mW cm⁻² which is 2.76% higher than 67.23 mW cm⁻² of the new-standard MEA at 80 °C and 2 M methanol concentration. The best improvement in power density, 27.09%, was obtained at low temperature and low methanol concentration of 30 °C and 1 M. The power density was 25.30 mW cm⁻² when compare to 19.91 mW cm⁻² of the new-standard MEA. These results suggest that the methanol barrier layer and the modified morphology of catalyst layer accomplish the aim of improving DMFC performance.

APA, Harvard, Vancouver, ISO, and other styles

32

Hacquard, Alexandre. "Improving and Understanding Direct Methanol Fuel Cell (DMFC) Performance." Link to electronic thesis, 2005. http://www.wpi.edu/Pubs/ETD/Available/etd-050505-151501/.

Full text

APA, Harvard, Vancouver, ISO, and other styles

33

Yin, Xiuli. "Synthesizing methanol from biomass derived syngas." Click to view the E-thesis via HKUTO, 2004. http://sunzi.lib.hku.hk/hkuto/record/B31456844.

Full text

APA, Harvard, Vancouver, ISO, and other styles

34

Geissler, Konrad. "Wasserstoffgewinnung aus Methanol für PEM-Brennstoffzellen /." [S.l.] : [s.n.], 2002. http://library.epfl.ch/theses/?nr=2442.

Full text

APA, Harvard, Vancouver, ISO, and other styles

35

Ritzkopf, Inga. "Kupfer-Katalysatoren für die Methanol-Dampfreformierung." [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=974923494.

Full text

APA, Harvard, Vancouver, ISO, and other styles

36

Hoffmann, Jens. "Methanol-Oxidation an getragenen Pd-Modellkatalysatoren." [S.l. : s.n.], 2003. http://www.diss.fu-berlin.de/2003/128/index.html.

Full text

APA, Harvard, Vancouver, ISO, and other styles

37

Coteron, Almudena. "Methanol synthesis by amorphous metal catalysts." Thesis, University of Cambridge, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240079.

Full text

APA, Harvard, Vancouver, ISO, and other styles

38

Yin, Xiuli, and 陰秀麗. "Synthesizing methanol from biomass derived syngas." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B31456844.

Full text

APA, Harvard, Vancouver, ISO, and other styles

39

Dennison, P. R. "NMR studies of methanol synthesis catalysts." Thesis, University of East Anglia, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383245.

Full text

APA, Harvard, Vancouver, ISO, and other styles

40

Fuller, G. P. "Methanol carbonylation with metal/zeolite catalysts." Thesis, Nottingham Trent University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369252.

Full text

APA, Harvard, Vancouver, ISO, and other styles

41

Aitani, Abdullah Mohamed. "Synthesis of light olefins from methanol." Thesis, City University London, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357480.

Full text

APA, Harvard, Vancouver, ISO, and other styles

42

Wawata, Ibrahim. "Methanol oxidation on molybdenum oxide catalysts." Thesis, Cardiff University, 2015. http://orca.cf.ac.uk/74613/.

Full text

APA, Harvard, Vancouver, ISO, and other styles

43

Alshehri, Abdulmohsen. "Methanol oxidation on transition elements oxides." Thesis, Cardiff University, 2013. http://orca.cf.ac.uk/47041/.

Full text

Abstract:

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.

APA, Harvard, Vancouver, ISO, and other styles

44

Sargeant, Stephanie L. "Microbial utilisation of methanol in seawater." Thesis, University of Warwick, 2013. http://wrap.warwick.ac.uk/60569/.

Full text

Abstract:

Methylotrophs are aerobic bacteria that use methanol as a carbon and/or energy source. They are widespread but have not been extensively studied in marine environments. Seawater 14C tracer studies were combined with molecular biological cultivation- independent techniques (polymerase chain reactions using 16S rRNA and mxaF gene specific primers, 454 pyrosequencing) to investigate temporal and spatial variability in rates of microbial methanol utilisation and methylotrophic community composition in temperate coastal waters of the western English Channel, UK (WEC) and the Atlantic Ocean (Atlantic Meridional Transect 19). Microbial methanol dissimilation rates were, on average, thirteen times higher in waters of the WEC (0.65–11.2 nmol l-1h-1) than in open ocean waters of the Atlantic (0.01–1.7 nmol l-1h-1), with maximum rates found during winter months in the WEC. Highest methanol dissimilation rates in the Atlantic were measured in the north subtropical gyre of up to eight times higher than other Atlantic regions. Microbial methanol assimilation rates in the Atlantic Ocean (0.01–2.2 x10-2 nmol l-1h-1) were up to four times higher than those from the WEC (0.04–2.6 x10-2 nmol l-1h-1). Methanol assimilation rates from the WEC displayed seasonal maxima during summer, but showed methanol bacterial growth efficiency (BGEM) of <1% all year. Overall, assimilation rates were highest in the equatorial upwelling where BGEM reached 17%. Methanol assimilation rates showed a significant positive correlation with bacterial leucine incorporation in contrast to methanol dissimilation, which showed a negative relationship. Methanol dissimilation rates strongly correlated with the abundance of bacteria of the SAR11 clade, previously shown to utilise methanol as an energy source. The first basin scale approach using 454 pyrosequencing in the Atlantic revealed a remarkable increase in bacterial diversity in the nutrient limited southern gyre. Use of mxaF PCR primers also confirmed the ubiquitous presence of methylotrophic bacteria throughout the top 200m of the Atlantic Ocean.

APA, Harvard, Vancouver, ISO, and other styles

45

Burton, Shirley Margaret. "Aspects of methanol metabolism in methylotrophs." Thesis, University of Leicester, 1990. http://hdl.handle.net/2381/35188.

Full text

Abstract:

The environmental regulation of methanol and formaldehyde metabolism by Methylophilus methylotrophus was examined by varying the growth conditions imposed upon cells in continuous culture and measuring the activities of key metabolic enzymes. Methanol dehydrogenase was repressed by the presence of high standing concentrations of methanol, whereas hexulose 6-phosphate synthase was constitutive and the glucose 6-phosphate and 6-phosphogluconate dehydrogenases were regulated only by the growth rate. It is concluded that the observed regulation of these enzymes occurs in order to achieve the required in situ rates of energy conservation and carbon flux demanded by the imposed growth rate. The control of flux through the methanol oxidase system of M. methylotrophus was examined in oxygen-limited cultures (D = 0.04 h-1). It was determined that the terminal oxidase (cytochrome oxidase co) does not exert significant control over flux in these cells. In methanol-limited cultures (D = 0.18 h-1) major control of flux through the methanol oxidase system was exerted by the cytochrome c pool. Hexulose 6-phosphate synthase of M. methylotrophus was found to be loosely associated with the cytoplasmic side of the membrane, mirroring the location of methanol dehydrogenase on the periplasmic side of the membrane. It is suggested that juxtapositioning of the formaldehyde-producing and -fixing enzymes on opposite sides of the membrane may help to reduce the amount of this potentially toxic metabolite which is released into the cytoplasm. Methanol dehydrogenase, hexulose 6-phosphate synthase and cytochrome Cl were purified from M. methylotrophus and antibodies raised against them. A wide variety of methylotrophs (including obligate or restricted-facultative and facultative bacteria and methylotrophic yeasts) were screened, by SDS-PAGE and Western blotting, for proteins which cross-react with the antisera. Only organisms which were closely related to M. methylotrophus (i.e. Gram-negative bacteria possessing the ribulose monophosphate pathway) gave any cross-reaction with the antisera. Two serologically distinct types methanol dehydrogenase and hexulose 6-phosphate synthase were therfore distinguished.

APA, Harvard, Vancouver, ISO, and other styles

46

Okpo, Emmanuel. "Photocatalytic conversion of carbondioxide to methanol /." Available to subscribers only, 2009. http://proquest.umi.com/pqdweb?did=1879983281&sid=14&Fmt=2&clientId=1509&RQT=309&VName=PQD.

Full text

APA, Harvard, Vancouver, ISO, and other styles

47

Luo, Hongze. "Proton conducting polymer composite membrane development for Direct Methanol Fuel Cell applications." Thesis, University of Western Cape, 2008. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_1362_1262901908.

Full text

Abstract:

The objective of this study was thus to prepare highly proton condictivity membranes that are cheap to manufacture and have low methanol permeability.

APA, Harvard, Vancouver, ISO, and other styles

48

Vidaković, Tanja. "Kinetics of methanol electrooxidation on PtRu catalysts in a membrane electrode assembly Kinetik der Elektrooxidation von Methanol an PtRu Katalysatoren auf einer Membranelektrode /." [S.l. : s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=976036134.

Full text

APA, Harvard, Vancouver, ISO, and other styles

49

Zhou, Ling. "Model studies of methanol selective oxidation over copper catalysts." [S.l. : s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=976146614.

Full text

APA, Harvard, Vancouver, ISO, and other styles

50

Genger, Thomas. "Mikrokinetische Untersuchungen zur Methanol-Synthese an Cu-Trägerkatalysatoren." [S.l. : s.n.], 2000. http://deposit.ddb.de/cgi-bin/dokserv?idn=958990131.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Dissertations / Theses on the topic 'Methanol'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles