Artículos de revistas: "Methane"

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Tselishchev, Oleksii, Ayodeji Ijagbuji, Maryna Loriia y Vanadii Nosach. "Synthesis of Methanol from Methane in Cavitation Field". Chemistry & Chemical Technology 12, n.º 1 (21 de marzo de 2018): 69–73. http://dx.doi.org/10.23939/chcht12.01.069.

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Benstead, J., G. M. King y H. G. Williams. "Methanol Promotes Atmospheric Methane Oxidation by Methanotrophic Cultures and Soils". Applied and Environmental Microbiology 64, n.º 3 (1 de marzo de 1998): 1091–98. http://dx.doi.org/10.1128/aem.64.3.1091-1098.1998.

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ABSTRACT Two methanotrophic bacteria, Methylobacter albus BG8 and Methylosinus trichosporium OB3b, oxidized atmospheric methane during batch growth on methanol. Methane consumption was rapidly and substantially diminished (95% over 9 days) when washed cell suspensions were incubated without methanol in the presence of atmospheric methane (1.7 ppm). Methanotrophic activity was stimulated after methanol (10 mM) but not methane (1,000 ppm) addition. M. albus BG8 grown in continuous culture for 80 days with methanol retained the ability to oxidize atmospheric methane and oxidized methane in a chemostat air supply. Methane oxidation during growth on methanol was not affected by methane deprivation. Differences in the kinetics of methane uptake (apparent Km andV max) were observed between batch- and chemostat-grown cultures. The V max and apparent Km values (means ± standard errors) for methanol-limited chemostat cultures were 133 ± 46 nmol of methane 108 cells−1 h−1and 916 ± 235 ppm of methane (1.2 μM), respectively. These values were significantly lower than those determined with batch-grown cultures (V max of 648 ± 195 nmol of methane 108 cells−1 h−1 and apparent Km of 5,025 ± 1,234 ppm of methane [6.3 μM]). Methane consumption by soils was stimulated by the addition of methanol. These results suggest that methanol or other nonmethane substrates may promote atmospheric methane oxidation in situ.

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Jensen, Sigmund, Anders Priemé y Lars Bakken. "Methanol Improves Methane Uptake in Starved Methanotrophic Microorganisms". Applied and Environmental Microbiology 64, n.º 3 (1 de marzo de 1998): 1143–46. http://dx.doi.org/10.1128/aem.64.3.1143-1146.1998.

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ABSTRACT Methanotrophs in enrichment cultures grew and sustained atmospheric methane oxidation when supplied with methanol. If they were not supplied with methanol or formate, their atmospheric methane oxidation came to a halt, but it was restored within hours in response to methanol or formate. Indigenous forest soil methanotrophs were also dependent on a supply of methanol upon reduced methane access but only when exposed to a methane-free atmosphere. Their immediate response to each methanol addition, however, was to shut down the oxidation of atmospheric methane and to reactivate atmospheric methane oxidation as the methanol was depleted.

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4

Blankenship, Andrea N., Manoj Ravi y Jeroen A. van Bokhoven. "Esterification Product Protection Strategies for Direct and Selective Methane Conversion". CHIMIA International Journal for Chemistry 75, n.º 4 (28 de abril de 2021): 305–10. http://dx.doi.org/10.2533/chimia.2021.305.

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A scale-flexible process for the direct and selective oxidation of methane to primary oxygenates is of great interest, however, a commercially feasible approach has yet to be realized due to a number of challenges. Low product yields imposed by a well-established selectivity-conversion limit are particularly burdensome for direct methane-to-methanol chemistry. One strategy that has emerged to break out of this limit is the in situ esterification of produced methanol to the more oxidation-resistant methyl ester. However, these methaneto-methyl-ester approaches still elude commercialization despite their unprecedented high yields. Herein, we outline some of the key barriers that hinder the commercial prospects of this otherwise promising route for highyield direct catalytic methane conversion, including extremely corrosive reagents, homogeneous catalysts, and inviable oxidants. We then highlight directions to address these challenges while maintaining the characteristic high performance of these systems. These discussions support the efficacy of product protection strategies for the direct, selective oxidation of methane and encourage future work in developing creative solutions to merge this promising chemistry with more practical industrial requirements.

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5

Chun, Jin Woo y Rayford G. Anthony. "Partial oxidation of methane, methanol, and mixtures of methane and methanol, methane and ethane, and methane, carbon dioxide, and carbon monoxide". Industrial & Engineering Chemistry Research 32, n.º 5 (mayo de 1993): 788–95. http://dx.doi.org/10.1021/ie00017a004.

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6

Xu, Zhen Chao y Eun Duck Park. "Gas-Phase Selective Oxidation of Methane into Methane Oxygenates". Catalysts 12, n.º 3 (9 de marzo de 2022): 314. http://dx.doi.org/10.3390/catal12030314.

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Methane is an abundant resource and its direct conversion into value-added chemicals has been an attractive subject for its efficient utilization. This method can be more efficient than the present energy-intensive indirect conversion of methane via syngas, a mixture of CO and H2. Among the various approaches for direct methane conversion, the selective oxidation of methane into methane oxygenates (e.g., methanol and formaldehyde) is particularly promising because it can proceed at low temperatures. Nevertheless, due to low product yields this method is challenging. Compared with the liquid-phase partial oxidation of methane, which frequently demands for strong oxidizing agents in protic solvents, gas-phase selective methane oxidation has some merits, such as the possibility of using oxygen as an oxidant and the ease of scale-up owing to the use of heterogeneous catalysts. Herein, we summarize recent advances in the gas-phase partial oxidation of methane into methane oxygenates, focusing mainly on its conversion into formaldehyde and methanol.

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7

Sedov, I. V., V. S. Arutyunov, M. V. Tsvetkov, D. N. Podlesniy, M. V. Salganskaya, A. Y. Zaichenko, Y. Y. Tsvetkova et al. "Evaluation of the Possibility to Use Coalbed Methane to Produce Methanol Both by Direct Partial Oxidation and From Synthesis Gas". Eurasian Chemico-Technological Journal 24, n.º 2 (25 de julio de 2022): 157. http://dx.doi.org/10.18321/ectj1328.

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The possibility of using coalbed methane to produce methanol is assessed. Methanol can be obtained from methane both by direct partial oxidation and from synthesis gas formed through the oxidative conversion of methane. Thermodynamic analysis of coalbed methane conversion was carried out to determine the conditions for obtaining synthesis gas with the ratio [H2]/[CO] = 2, which is optimal for methanol production. The system consisting of methane, nitrogen, and oxygen, with different contents of oxygen and water vapor, was considered. The fuel-air equivalence ratio varied in the range from 2 to 4. The optimal conditions for obtaining synthesis gas for the production of methanol is the use of a mixture with an equivalence ratio of at least 4. It has also been shown that the addition of water vapor leads to an increase in the [H2]/[CO] ratio. Direct gas-phase oxidation of methane to methanol opens up the possibility of complex use of coal mining waste, including not only coalbed methane but also a large amount of coal waste accumulated during coal mining and beneficiation.

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8

Li, Zhi, Yanjun Chen, Zean Xie, Weiyu Song, Baijun Liu y Zhen Zhao. "Rational Design of the Catalysts for the Direct Conversion of Methane to Methanol Based on a Descriptor Approach". Catalysts 13, n.º 8 (21 de agosto de 2023): 1226. http://dx.doi.org/10.3390/catal13081226.

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The direct oxidation of methane to methanol as a liquid fuel and chemical feedstock is arguably the most desirable methane conversion pathway. Currently, constructing and understanding linear scaling relationships between the fundamental physical or chemical properties of catalysts and their catalytic performance to explore suitable descriptors is crucial for theoretical research on the direct conversion of methane to methanol. In this review, we summarize the energy, electronic, and structural descriptors used to predict catalytic activity. Fundamentally, these descriptors describe the redox properties of active sites from different dimensions. We further explain the moderate principle of descriptors in methane-to-methanol catalyst design and provide related application work. Simultaneously, the underlying activity limitation of methane activation and active species generation is revealed. Based on the selectivity descriptor, the inverse scaling relationship limitation between methane conversion and methanol selectivity is quantitatively understood. Finally, multiscale strategies are proposed to break the limitation and achieve the simultaneous enhancement of activity and selectivity. This descriptor-based review provides theoretical insights and guidance to accelerate the understanding, optimization, and design of efficient catalysts for direct methane-to-methanol conversion.

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9

JACOBY, MITCH. "TURNING METHANE INTO METHANOL". Chemical & Engineering News 87, n.º 35 (31 de agosto de 2009): 7. http://dx.doi.org/10.1021/cen-v087n035.p007.

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10

Shen, Haiqing, Huihong Liao, Qiyang Wang, Cangsu Xu, Kai Liu y Wenhua Zhou. "Effects of methane addition on the laminar burning velocity and Markstein length of methanol/air premixed flame". Thermal Science, n.º 00 (2023): 193. http://dx.doi.org/10.2298/tsci230201193s.

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Adding methane to methanol can solve the problem of difficult cold starts of methanol engines. Therefore, it is important to understand the combustion of methane and methanol fuel blends. Because of this, this study explores the effect of methane addition on the laminar burning velocity and Markstein length of methanol/methane premixed flames under stoichiometric conditions at the initial temperatures of 353 K, 373 K, and 393 K, initial pressures of 1 bar, 2 bar, and 4 bar, using methane addition ratios of 0%, 25%, 50%, 75% and 100% in a constant volume combustion chamber. The results show that the laminar burning velocity decreases linearly with the increase of methane addition ratio due to the linear decrease of the Arrhenius factor. The sensitivity analysis revealed that the kinetic effect is the main reason for the inhibition of laminar burning velocity, which is insensitive to initial temperature but enhanced at a high initial pressure. The Markstein length decreases with the addition of methane and the increase of initial pressure, which is mainly caused by the high mass diffusivity of methane and the decrease of flame thickness due to the increase of initial pressure.

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11

Yarakhmedov, M. B., A. G. Kiiamov, M. E. Semenov, A. P. Semenov y A. S. Stoporev. "Peculiarities of Decomposition of Gas Hydrates in the Presence of Methanol at Atmospheric Pressure". Chemistry and Technology of Fuels and Oils 634, n.º 6 (2022): 40–43. http://dx.doi.org/10.32935/0023-1169-2022-634-6-40-43.

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The study of the decomposition process of gas hydrates at atmospheric pressure and temperatures below 0°C revealed that methanol could affect this process in different ways, depending on its saturation with environmental components. Indeed, dueto the absorption of methane from the hydrate by methanol, the onset of its decomposition is observed at lower temperatures.Nevertheless, decomposition proceeds more slowly than with pure methane hydrate. When the methanol surrounding the methane hydrate is saturated with other medium components, the hydrate dissociation occurs at the equilibrium temperature (when intersecting the hydrate-ice-gas curve in a system without additives) regardless of the alcohol concentration. A similar situation is observed with hydrate obtained from a methane-propane gas mixture; however, under experimental conditions, ice beginsto melt at a lower temperature compared to the dissociation point of methane-propane hydrate (in the case of methane hydrate, the situation is reversed: the hydrate is less stable). High concentrations of methanol (above 40 mass%) lead to a significant decrease in the temperature of hydrate decomposition. The data obtained show that methanol in low dosages (about 10 mass%) can be usedfor gas storage and transportation since, under certain conditions, it does not shift the equilibrium curve of hydrate formation and slows down the process of methane hydrate decomposition.

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12

Jin, Zhu, Liang Wang, Erik Zuidema, Kartick Mondal, Ming Zhang, Jian Zhang, Chengtao Wang et al. "Hydrophobic zeolite modification for in situ peroxide formation in methane oxidation to methanol". Science 367, n.º 6474 (9 de enero de 2020): 193–97. http://dx.doi.org/10.1126/science.aaw1108.

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Selective partial oxidation of methane to methanol suffers from low efficiency. Here, we report a heterogeneous catalyst system for enhanced methanol productivity in methane oxidation by in situ generated hydrogen peroxide at mild temperature (70°C). The catalyst was synthesized by fixation of AuPd alloy nanoparticles within aluminosilicate zeolite crystals, followed by modification of the external surface of the zeolite with organosilanes. The silanes appear to allow diffusion of hydrogen, oxygen, and methane to the catalyst active sites, while confining the generated peroxide there to enhance its reaction probability. At 17.3% conversion of methane, methanol selectivity reached 92%, corresponding to methanol productivity up to 91.6 millimoles per gram of AuPd per hour.

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13

Michalkiewicz, Beata. "Assessment of the possibility of the methane to methanol transformation". Polish Journal of Chemical Technology 10, n.º 2 (1 de enero de 2008): 20–26. http://dx.doi.org/10.2478/v10026-008-0023-5.

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Assessment of the possibility of the methane to methanol transformation The methane to methanol conversion via esterification is an interesting method which makes it possible to eliminate the otherwise necessary phase of obtaining synthesis gas. On the basis of laboratory investigations mass balances for this process were determined. Preliminary assessment of the way of conducting the process and possibilities of practical applications of this technology was also made. It was pointed out that regardless of any possible modifications of methane to methanol conversion via esterification redundant sulfuric acid will always be produced during ester hydrolysis. Production of methanol from methane using this method can only be done when it is combined with producing other substances, which needs using H2SO4.

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14

Omata, K., N. Fukuoka y K. Fujimoto. "Methane partial oxidation to methanol-solid initiated homogeneous methane oxidation". Catalysis Letters 12, n.º 1-3 (1992): 227–30. http://dx.doi.org/10.1007/bf00767204.

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15

Yuniar, Gita, Wibawa Hendra Saputera, Dwiwahju Sasongko, Rino R. Mukti, Jenny Rizkiana y Hary Devianto. "Recent Advances in Photocatalytic Oxidation of Methane to Methanol". Molecules 27, n.º 17 (26 de agosto de 2022): 5496. http://dx.doi.org/10.3390/molecules27175496.

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Methane is one of the promising alternatives to non-renewable petroleum resources since it can be transformed into added-value hydrocarbon feedstocks through suitable reactions. The conversion of methane to methanol with a higher chemical value has recently attracted much attention. The selective oxidation of methane to methanol is often considered a “holy grail” reaction in catalysis. However, methanol production through the thermal catalytic process is thermodynamically and economically unfavorable due to its high energy consumption, low catalyst stability, and complex reactor maintenance. Photocatalytic technology offers great potential to carry out unfavorable reactions under mild conditions. Many in-depth studies have been carried out on the photocatalytic conversion of methane to methanol. This review will comprehensively provide recent progress in the photocatalytic oxidation of methane to methanol based on materials and engineering perspectives. Several aspects are considered, such as the type of semiconductor-based photocatalyst (tungsten, titania, zinc, etc.), structure modification of photocatalyst (doping, heterojunction, surface modification, crystal facet re-arrangement, and electron scavenger), factors affecting the reaction process (physiochemical characteristic of photocatalyst, operational condition, and reactor configuration), and briefly proposed reaction mechanism. Analysis of existing challenges and recommendations for the future development of photocatalytic technology for methane to methanol conversion is also highlighted.

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16

Dutta, Buddhadeb. "Metal Incorporated Zeolites as Heterogeneous Catalysts in the Selective Partial Oxidation of Methane to Methanol: A Review". Asian Journal of Chemistry 36, n.º 9 (30 de agosto de 2024): 1977–87. http://dx.doi.org/10.14233/ajchem.2024.32083.

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Methane, being a potential greenhouse gas, is a very serious environmental concern nowadays. The valorization of methane to valuable chemicals like methanol has long been considered as an effective remedy to this problem. But, in spite of several attempts, the production of methanol directly from methane remains largely challenging, both in laboratory scale and in industrial level, because of low reactivity of methane and challenges in product recovery. In present review, the developments in the application of different heterogeneous catalysts in oxidation of methane to produce methanol directly, the ‘holy grail’ reaction in chemistry is discussed, with the main focus on the metal exchanged porous zeolite matrices as heterogeneous catalysts. The different reaction parameters like the nature of oxidants, reaction conditions, zeolite pore sizes, the metal loading ratio are also critically reviewed.

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17

Xu, Qingliang. "Reviews on the Production and Application of Methane". Applied and Computational Engineering 3, n.º 1 (25 de mayo de 2023): 96–100. http://dx.doi.org/10.54254/2755-2721/3/20230358.

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This paper discusses the properties, production and application of methane. It first explains how methanes tetrahedral structure and the slightly polar C-H bond give rise to its physical properties of low melting and boiling point and its chemical properties of oxidation and substitution reaction. It then looks into the three most significant natural and artificial methods to produce methane, including biological decomposition, geological methane generation and methanation. It further identifies methane as a source of clean energy. Compared to traditional fossil fuels such as coal, Methane is more energy efficient and has a much lower carbon emission than traditional fossil fuels such as coal and cruel oil. In terms of using methane as a chemical stock to produce hydrogen, this paper focuses on the chemical mechanism of steam methane reforming (SMR) and methane pyrolysis.

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18

Kunkely, Horst y Arnd Vogler. "Photooxidation of Methane to Methanol by Perrhenate in Water under Ambient Conditions". Zeitschrift für Naturforschung B 68, n.º 8 (1 de agosto de 2013): 891–94. http://dx.doi.org/10.5560/znb.2013-3104.

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The oxidation of methane to methanol takes place selectively by the photolysis of perrhenate in aqueous solution in the presence of methane. This photoreaction is formally an oxygen atom transfer. Because the reoxidation of the reduced perrhenate is accomplished with hydrogen peroxide the overall process can be viewed as photocatalytic oxidation of methane to methanol: CH4 + H2O2 → CH3OH+ H2O.

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19

Mehmood, Adeel, Sang Youn Chae y Eun Duck Park. "Low-Temperature Electrochemical Oxidation of Methane into Alcohols". Catalysts 14, n.º 1 (12 de enero de 2024): 58. http://dx.doi.org/10.3390/catal14010058.

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The direct oxidation of methane to methanol is considered challenging due to the intrinsically low reactivity of the C–H bond of methane and the formation of a large number of unstable intermediates (methanol, formaldehyde, and formic acid) relative to the yield of methane. However, promising advances have recently been reported in this area based on the use of electrochemical systems that differ from traditional thermal catalysis. In this review, the recent advances in direct and indirect electrochemical methane conversion with homogeneous catalysts are reviewed and discussed, especially under low-temperature conditions. Finally, the limitations of the current electrochemical methane conversion technology and future research directions are discussed.

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20

Lee, Hyunyong, Inchul Jung, Gilltae Roh, Youngseung Na y Hokeun Kang. "Comparative Analysis of On-Board Methane and Methanol Reforming Systems Combined with HT-PEM Fuel Cell and CO2 Capture/Liquefaction System for Hydrogen Fueled Ship Application". Energies 13, n.º 1 (2 de enero de 2020): 224. http://dx.doi.org/10.3390/en13010224.

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This study performs energetic and exergetic comparisons between the steam methane reforming and steam methanol reforming technologies combined with HT-PEMFC and a carbon capture/liquefaction system for use in hydrogen-fueled ships. The required space for the primary fuel and captured/liquefied CO2 and the fuel cost have also been investigated to find the more advantageous system for ship application. For the comparison, the steam methane reforming-based system fed by LNG and the steam methanol reforming-based system fed by methanol have been modeled in an Aspen HYSYS environment. All the simulations have been conducted at a fixed Wnet, electrical (475 kW) to meet the average shaft power of the reference ship. Results show that at the base condition, the energy and exergy efficiencies of the methanol-based system are 7.99% and 1.89% higher than those of the methane-based system, respectively. The cogeneration efficiency of the methane-based system is 7.13% higher than that of the methanol-based system. The comparison of space for fuel and CO2 storage reveals that the methanol-based system requires a space 1.1 times larger than that of the methane-based system for the total voyage time, although the methanol-based system has higher electrical efficiency. In addition, the methanol-based system has a fuel cost 2.2 times higher than that of the methane-based system to generate 475 kW net of electricity for the total voyage time.

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21

Xin, Jia-Ying, Li-Rui Sun, Hui-Ying Lin, Shuai Zhang y Chun-Gu Xia. "Hybridization of Particulate Methane Monooxygenase by Methanobactin-Modified AuNPs". Molecules 24, n.º 22 (7 de noviembre de 2019): 4027. http://dx.doi.org/10.3390/molecules24224027.

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Particulate methane monooxygenase (pMMO) is a characteristic membrane-bound metalloenzyme of methane-oxidizing bacteria that can catalyze the bioconversion of methane to methanol. However, in order to achieve pMMO-based continuous methane-to-methanol bioconversion, the problems of reducing power in vitro regeneration and pMMO stability need to be overcome. Methanobactin (Mb) is a small copper-chelating molecule that functions not only as electron carrier for pMMO catalysis and pMMO protector against oxygen radicals, but also as an agent for copper acquisition and uptake. In order to improve the activity and stability of pMMO, methanobactin–Cu (Mb–Cu)-modified gold nanoparticle (AuNP)–pMMO nanobiohybrids were straightforwardly synthesized via in situ reduction of HAuCl4 to AuNPs in a membrane fraction before further association with Mb–Cu. Mb–Cu modification can greatly improve the activity and stability of pMMO in the AuNP–pMMO nanobiohybrids. It is shown that the Mb–Cu-modified AuNP–pMMO nanobiohybrids can persistently catalyze the conversion of methane to methanol with hydroquinone as electron donor. The artificial heterogeneous nanobiohybrids exhibited excellent reusability and reproducibility in three cycles of catalysis, and they provide a model for achieving hydroquinone-driven conversion of methane to methanol.

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22

Brantner, Christine A., Lorie A. Buchholz, Claudia L. McSwain, Laura L. Newcomb, Charles C. Remsen y Mary Lynne Perille Collins. "Intracytoplasmic membrane formation in Methylomicrobium album BG8 is stimulated by copper in the growth medium". Canadian Journal of Microbiology 43, n.º 7 (1 de julio de 1997): 672–76. http://dx.doi.org/10.1139/m97-095.

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Methylomicrobium album BG8 uses methane as its sole source of carbon and energy. The oxidation of methane to methanol is catalyzed by the enzyme methane monooxygenase. Methane monooxygenase activity, intracytoplasmic membrane abundance, and cell mass increased with increasing copper concentration in the medium. When copper was added to copper-deficient cultures, cell mass and intracytoplasmic membrane structure increased. These findings are consistent with the presence of copper in the particulate methane monooxygenase. Methane monooxygenase activity and intracytoplasmic membrane abundance were correlated, suggesting that the methane monooxygenase may be involved in intracytoplasmic membrane proliferation.Key words: Methylomicrobium album BG8, copper, intracytoplasmic membrane, methane monooxygenase.

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23

Semenov, A. P., T. B. Tulegenov, R. I. Mendgaziev, A. S. Stoporev, V. A. Istomin y V. A. Vinokurov. "Effect of Methanol on Methane Hydrate Nucleation and Growth Kinetics". Chemistry and Technology of Fuels and Oils 638, n.º 4 (2023): 8–13. http://dx.doi.org/10.32935/0023-1169-2023-638-4-8-13.

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In the present work, we experimentally investigated the nucleation and growth kinetics of methane hydrate in the presence of aqueous methanol solutions at alcohol concentrations of 0, 1, 2.5, 5, 10, and 20 mass %. It was found that the addition of methanol statistically significantly reduces the supercooling of the methane hydrate onset ΔTo even at low concentrations. The value of ΔTo decreases bya factor of 5 when transitioning from water to 20 mass% methanol. We have observed that as the alcohol content increases, there isa correlation with an increase in the amount of hydrate at the end of the cooling stage. Adding methanol to water also increases the rate of methane hydrate growth. Thus, our experimental data indicate the role of methanol as a kinetic promoter of methane hydrate nucleation and growth, and the dual nature of methanol which is also a thermodynamic hydrate inhibitor.

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Lind, Natalie M., Natalie S. Joe, Brian S. Newell y Aimee M. Morris. "High Yielding, One-Pot Synthesis of Bis(1H-indazol-1-yl)methane Catalyzed by 3d-Metal Salts". Reactions 3, n.º 1 (4 de enero de 2022): 59–69. http://dx.doi.org/10.3390/reactions3010005.

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Synthetic access to poly(indazolyl)methanes has limited their study despite their structural similarity to the highly investigated chelating poly(pyrazolyl)methanes and their potentially important indazole moiety. Herein is presented a high yielding, one-pot synthesis for the 3d-metal catalyzed formation of bis(1H-indazol-1-yl)methane from 1H-indazole utilizing dimethylsulfoxide as the methylene source. Complete characterization of bis(1H-indazol-1-yl)methane is given with 1H and 13C NMR, UV/Vis, FTIR, high resolution mass spectrometry and for the first time, single crystal X-ray diffraction. This simple, inexpensive pathway to yield exclusively bis(1H-indazol-1-yl)methane provides synthetic access to further investigate the coordination and potential applications of the family of bis(indazolyl)methanes.

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Moran, James J., Christopher H. House, Katherine H. Freeman y James G. Ferry. "Trace methane oxidation studied in several Euryarchaeota under diverse conditions". Archaea 1, n.º 5 (2005): 303–9. http://dx.doi.org/10.1155/2005/650670.

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We used13C-labeled methane to document the extent of trace methane oxidation byArchaeoglobus fulgidus,Archaeoglobus lithotrophicus,Archaeoglobus profundus,Methanobacterium thermoautotrophicum,Methanosarcina barkeriandMethanosarcina acetivorans. The results indicate trace methane oxidation during growth varied among different species and among methanogen cultures grown on different substrates. The extent of trace methane oxidation byMb. thermoautotrophicum(0.05 ± 0.04%, ± 2 standard deviations of the methane produced during growth) was less than that byM. barkeri(0.15 ± 0.04%), grown under similar conditions with H2and CO2.Methanosarcina acetivoransoxidized more methane during growth on trimethylamine (0.36 ± 0.05%) than during growth on methanol (0.07 ± 0.03%). This may indicate that, inM. acetivorans, either a methyltransferase related to growth on trimethylamine plays a role in methane oxidation, or that methanol is an intermediate of methane oxidation. Addition of possible electron acceptors (O2, NO3–, SO22–, SO32–) or H2to the headspace did not substantially enhance or diminish methane oxidation inM. acetivoranscultures.Separate growth experiments with FAD and NAD+showed that inclusion of these electron carriers also did not enhance methane oxidation. Our results suggest trace methane oxidized during methanogenesis cannot be coupled to the reduction of these electron acceptors in pure cultures, and that the mechanism by which methane is oxidized in methanogens is independent of H2concentration. In contrast to the methanogens, species of the sulfate-reducing genusArchaeoglobusdid not significantly oxidize methane during growth (oxidizing 0.003 ± 0.01% of the methane provided toA. fulgidus, 0.002 ± 0.009% toA. lithotrophicusand 0.003 ± 0.02% toA. profundus). Lack of observable methane oxidation in the threeArchaeoglobusspecies examined may indicate that methyl-coenzyme M reductase, which is not present in this genus, is required for the anaerobic oxidation of methane, consistent with the “reverse methanogenesis” hypothesis.

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Mao, Min, Lingmei Liu y Zhaohui Liu. "Recent Insights into Cu-Based Catalytic Sites for the Direct Conversion of Methane to Methanol". Molecules 27, n.º 21 (22 de octubre de 2022): 7146. http://dx.doi.org/10.3390/molecules27217146.

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Direct conversion of methane to methanol is an effective and practical process to improve the efficiency of natural gas utilization. Copper (Cu)-based catalysts have attracted great research attention, due to their unique ability to selectively catalyze the partial oxidation of methane to methanol at relatively low temperatures. In recent decades, many different catalysts have been studied to achieve a high conversion of methane to methanol, including the Cu-based enzymes, Cu-zeolites, Cu-MOFs (metal-organic frameworks) and Cu-oxides. In this mini review, we will detail the obtained evidence on the exact state of the active Cu sites on these various catalysts, which have arisen from the most recently developed techniques and the results of DFT calculations. We aim to establish the structure–performance relationship in terms of the properties of these materials and their catalytic functionalities, and also discuss the unresolved questions in the direct conversion of methane to methanol reactions. Finally, we hope to offer some suggestions and strategies for guiding the practical applications regarding the catalyst design and engineering for a high methanol yield in the methane oxidation reaction.

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27

Nahmatova, Gulshan, Latifa Gasanova y Tofig Nagiev. "Study of the Methanol Conversion into Dimethyl Ether Obtained in the Process of Biomimetic Methane Monooxidation by Hydrogen Peroxide". Materials Science Forum 1121 (14 de mayo de 2024): 119–28. http://dx.doi.org/10.4028/p-35bwu0.

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The monooxidation of methane into methanol was carried out on biomimetic heterogeneous catalyst – iron pentafluorotetraphenylporphyrin on Al2O3 (ImtOH), at atmospheric pressure and temperatures of 200-350°C, which resulted in liquid one-carbon compounds CH3OH (19.2%), CH2O (1.55%), CH3OCH3 (8.2%) with high selectivity and are widely used in the chemical industry. In order to establish the routes of these products formation and the mechanism for the methane conversion into them, the investigation of the methanol conversion reaction was carried out, as an intermediate compound of the methane oxidation, under identical conditions on the same catalyst.The result was only dimethyl ether with 100% selectivity. This proved that in this reaction system, methanol obtained from the methane monooxidation is converted only into dimethyl ether, and formaldehyde, in parallel with methanol, is formed from methane. The mechanisms of the elementary stages of the formation of methanol, formaldehyde and dimethyl ether on the surface of the bioimitator through the formation of an active complex (ImtOOH) are presented, in which the unity of the mechanisms of redox and acid-base catalysis traced within the framework of the principle of the bond redistribution chain (BRC), similar to enzymatic reactions.

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Rusmana, I., L. Karomah, A. Akhdiya y A. Suwanto. "Characteristics and activity of SpmoB domain of particulate methane monooxygenase expressed in Escherichia coli BL21 (DE3)". IOP Conference Series: Earth and Environmental Science 1271, n.º 1 (1 de diciembre de 2023): 012062. http://dx.doi.org/10.1088/1755-1315/1271/1/012062.

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Abstract Particulate methane monooxygenase is one of the methane monooxygenases of methanotrophic bacteria. The enzyme can convert methane to methanol in mild conditions. Cupredoxin domain recombinant protein (SpmoB) of particulate methane monooxygenase can oxidize methane to methanol. This protein was expressed in Escherichia coli BL21 (DE3) with Lac operon-based induction. SpmoB protein was isolated and refolded from the E. coli recombinant inclusion body. The pH and temperature dependence of SpmoB activity was also investigated to increase its activity. the SpmoB protein expressed by E. coli BL21 (DE3) is about 39 kDa. The SpmoB inclusion body was solubilized in 8 M urea followed by stepwise dialysis to get the active form SpmoB protein. The specific activity of the refolded protein was 0.46 methanol mg protein-1 min-1, which was higher than that of SpmoB from the previous study. The SpmoB was an acidic protein with the highest methanol production at pH six and a temperature of 30°C, which are higher than full-length pMMO. The SpmoB activity was stable at pH 6 to 8, and the Vmax and Km were 0.380 μM methanol s-1 and 44.27 μM, respectively.

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29

Vali, Seyed Alireza, Ahmad Abo Markeb, Javier Moral-Vico, Xavier Font y Antoni Sánchez. "Recent Advances in the Catalytic Conversion of Methane to Methanol: From the Challenges of Traditional Catalysts to the Use of Nanomaterials and Metal-Organic Frameworks". Nanomaterials 13, n.º 20 (13 de octubre de 2023): 2754. http://dx.doi.org/10.3390/nano13202754.

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Methane and carbon dioxide are the main contributors to global warming, with the methane effect being 25 times more powerful than carbon dioxide. Although the sources of methane are diverse, it is a very volatile and explosive gas. One way to store the energy content of methane is through its conversion to methanol. Methanol is a liquid under ambient conditions, easy to transport, and, apart from its use as an energy source, it is a chemical platform that can serve as a starting material for the production of various higher-value products. Accordingly, the transformation of methane to methanol has been extensively studied in the literature, using traditional catalysts as different types of zeolites. However, in the last few years, a new generation of catalysts has emerged to carry out this transformation with higher conversion and selectivity, and more importantly, under mild temperature and pressure conditions. These new catalysts typically involve the use of a highly porous supporting material such as zeolite, or more recently, metal-organic frameworks (MOFs) and graphene, and metallic nanoparticles or a combination of different types of nanoparticles that are the core of the catalytic process. In this review, recent advances in the porous supports for nanoparticles used for methane oxidation to methanol under mild conditions are discussed.

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30

Tang, Ping, Xiong Yang y Ying Shu Liu. "Active Carbon for Coal Mine Methane Separation by Pressure Swing Adsorption". Advanced Materials Research 236-238 (mayo de 2011): 586–90. http://dx.doi.org/10.4028/www.scientific.net/amr.236-238.586.

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Five types of active carbon’s adsorption isotherm of nitrogen at 77K were measured, and their adsorption characteristic were analysed. The results show AC1, AC2 and AC3 have a lot of micropores for they have high nitrogen adsorbance in low pressure at 77K. The HK model was employed to analysis the pore size distribution of the adsorbance. AC1 has most developed microspore structure, its surface area reached 1706㎡/g, and its pore size mainly concentrated at 4.6 angstroms. Then the five adsorbents’ adsorption isotherm on methane, oxygen and nitrogen at 298K, 308K and 318K were measured. Methane’s adsorption capacity on active carbon is much higher than nitrogen and oxygen, and the adsorbance of nitrogen and oxygen have little difference, so the coal mine methane could be regarded as the binary of methane and nitrogen on methane separation by adsorption method. AC1 has the highest methane adsorbance and equilibrium selectivity factor of methane to nitrogen. Then the adsorption heat was studied, the results show that the isosteric heat of methane on AC1 decreased from 20.6kJ/mol to 19.55kJ/mol when the adsorbance of methane increases from 0.4 mol/kg to 1.2mol/kg, and methane’s adsorption heat is higher than nitrogen.

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31

Li, Guoxing, Youjun Lu y Peter Glarborg. "Oxidation Kinetics of Methane and Methane/Methanol Mixtures in Supercritical Water". Industrial & Engineering Chemistry Research 61, n.º 11 (9 de marzo de 2022): 3889–99. http://dx.doi.org/10.1021/acs.iecr.1c04524.

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32

YOSHIZAWA, Kazunari, Takehiro OHTA y Tokio YAMABE. "Reaction Mechanism for the Methane-Methanol Conversion by Soluble Methane Monooxygenase." NIPPON KAGAKU KAISHI, n.º 7 (1998): 451–59. http://dx.doi.org/10.1246/nikkashi.1998.451.

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33

Meyet, Jordan, Alexander P. van Bavel, Andrew D. Horton, Jeroen A. van Bokhoven y Christophe Copéret. "Selective oxidation of methane to methanol on dispersed copper on alumina from readily available copper(ii) formate". Catalysis Science & Technology 11, n.º 16 (2021): 5484–90. http://dx.doi.org/10.1039/d1cy00789k.

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34

Arnarson, Logi, Per S. Schmidt, Mohnish Pandey, Alexander Bagger, Kristian S. Thygesen, Ifan E. L. Stephens y Jan Rossmeisl. "Fundamental limitation of electrocatalytic methane conversion to methanol". Physical Chemistry Chemical Physics 20, n.º 16 (2018): 11152–59. http://dx.doi.org/10.1039/c8cp01476k.

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35

Shteinman, A. A. "Bioinspired Oxidation of Methane: From Academic Models of Methane Monooxygenases to Direct Conversion of Methane to Methanol". Kinetics and Catalysis 61, n.º 3 (mayo de 2020): 339–59. http://dx.doi.org/10.1134/s0023158420030180.

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36

Kunkel, Benny, Dominik Seeburg, Tim Peppel, Matthias Stier y Sebastian Wohlrab. "Combination of Chemo- and Biocatalysis: Conversion of Biomethane to Methanol and Formic Acid". Applied Sciences 9, n.º 14 (12 de julio de 2019): 2798. http://dx.doi.org/10.3390/app9142798.

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In the present day, methanol is mainly produced from methane via reforming processes, but research focuses on alternative production routes. Herein, we present a chemo-/biocatalytic oxidation cascade as a novel process to currently available methods. Starting from synthetic biogas, in the first step methane was oxidized to formaldehyde over a mesoporous VOx/SBA-15 catalyst. In the second step, the produced formaldehyde was disproportionated enzymatically towards methanol and formic acid in equimolar ratio by formaldehyde dismutase (FDM) obtained from Pseudomonas putida. Two processing routes were demonstrated: (a) batch wise operation using free formaldehyde dismutase after accumulating formaldehyde from the first step and (b) continuous operation with immobilized enzymes. Remarkably, the chemo-/biocatalytic oxidation cascades generate methanol in much higher productivity compared to methane monooxygenase (MMO) which, however, directly converts methane. Moreover, production steps for the generation of formic acid were reduced from four to two stages.

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37

Wu, Linke, Wei Fan, Xun Wang, Hongxia Lin, Jinxiong Tao, Yuxi Liu, Jiguang Deng, Lin Jing y Hongxing Dai. "Methane Oxidation over the Zeolites-Based Catalysts". Catalysts 13, n.º 3 (16 de marzo de 2023): 604. http://dx.doi.org/10.3390/catal13030604.

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Zeolites have ordered pore structures, good spatial constraints, and superior hydrothermal stability. In addition, the active metal elements inside and outside the zeolite framework provide the porous material with adjustable acid–base property and good redox performance. Thus, zeolites-based catalysts are more and more widely used in chemical industries. Combining the advantages of zeolites and active metal components, the zeolites-based materials are used to catalyze the oxidation of methane to produce various products, such as carbon dioxide, methanol, formaldehyde, formic acid, acetic acid, and etc. This multifunction, high selectivity, and good activity are the key factors that enable the zeolites-based catalysts to be used for methane activation and conversion. In this review article, we briefly introduce and discuss the effect of zeolite materials on the activation of C–H bonds in methane and the reaction mechanisms of complete methane oxidation and selective methane oxidation. Pd/zeolite is used for the complete oxidation of methane to carbon dioxide and water, and Fe- and Cu-zeolite catalysts are used for the partial oxidation of methane to methanol, formaldehyde, formic acid, and etc. The prospects and challenges of zeolite-based catalysts in the future research work and practical applications are also envisioned. We hope that the outcome of this review can stimulate more researchers to develop more effective zeolite-based catalysts for the complete or selective oxidation of methane.

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38

Meyet, Jordan, Mark A. Newton, Jeroen A. van Bokhoven y Christophe Copéret. "Molecular Approach to Generate Cu(II) Sites on Silica for the Selective Partial Oxidation of Methane". CHIMIA International Journal for Chemistry 74, n.º 4 (29 de abril de 2020): 237–40. http://dx.doi.org/10.2533/chimia.2020.237.

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The selective partial oxidation of methane to methanol remains a great challenge in the field of catalysis. Cu-exchanged zeolites are promising materials, directly and selectively converting methane to methanol with high yield under cyclic conditions. However, the economic viability of these aluminosilicate materials for potential industrial applications remains a challenge. Exploring copper supported on non-microporous oxide supports and rationalising the structure/reactivity relationships extends the scope of material investigation and opens new possibilities. Recently, copper on alumina was demonstrated to be active and selective for the partial oxidation of methane. This work aims to explore the formation of well-defined Cu(II) oxo species on silica via surface organometallic chemistry and examines their reactivity for the selective transformation of methane to methanol. Isolated Cu(II) sites were generated via grafting of a tailored molecular precursor. Activation under oxidative conditions and subsequent removal of organic moieties from the grafted copper centres led to the formation of small copper (II) oxide clusters, which are active in the partial oxidation of methane under mild conditions, albeit significantly less efficient than the corresponding isolated Cu(II) sites on alumina.

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Guan, Xi’an, Yehong Wang, Xiumei Liu, Hong Du, Xinwen Guo y Zongchao Zhang. "Enhancing the Activity of Cu-MOR by Water for Oxidation of Methane to Methanol". Catalysts 13, n.º 7 (3 de julio de 2023): 1066. http://dx.doi.org/10.3390/catal13071066.

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As clean energy, methane has huge reserves and great development potential in the future. Copper zeolites are efficient in the oxidation of methane to methanol. Water has been confirmed as a source of oxygen to regenerate the copper-zeolite active sites to enable selective anaerobic oxidation of methane to methanol. In this work, we report that the methanol yield increased from 36 μmol/g (Cu-MOR1) to 92 μmol/g (Cu-MOR1-water) as a result of water enhancing the activity of copper ion-exchange mordenite catalyst. We show for the first time that water could convert inactive copper species into active copper species during catalyst activation. A combination of the XPS, FTIR, and NMR results indicates that water dissociates and then converts ZCuIIZ into ZCuII(OH) (where Z indicates framework O (Ofw) bonded to one isolated Al in a framework T-site, i.e., 1Al) and simultaneously produces a Brönsted acid site during catalyst activation. This finding can be used to tune the state of copper species and design highly active copper-zeolite catalysts for methane oxidation to methanol.

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40

Sharma, Richa, Hilde Poelman, Guy B. Marin y Vladimir V. Galvita. "Approaches for Selective Oxidation of Methane to Methanol". Catalysts 10, n.º 2 (6 de febrero de 2020): 194. http://dx.doi.org/10.3390/catal10020194.

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Methane activation chemistry, despite being widely reported in literature, remains to date a subject of debate. The challenges in this reaction are not limited to methane activation but extend to stabilization of the intermediate species. The low C-H dissociation energy of intermediates vs. reactants leads to CO2 formation. For selective oxidation, nature presents methane monooxygenase as a benchmark. This enzyme selectively consumes methane by breaking it down into methanol. To assemble an active site similar to monooxygenase, the literature reports Cu-ZSM-5, Fe-ZSM-5, and Cu-MOR, using zeolites and systems like CeO2/Cu2O/Cu. However, the trade-off between methane activation and methanol selectivity remains a challenge. Density functional theory (DFT) calculations and spectroscopic studies indicate catalyst reducibility, oxygen mobility, and water as co-feed as primary factors that can assist in enabling higher selectivity. The use of chemical looping can further improve selectivity. However, in all systems, improvements in productivity per cycle are required in order to meet the economical/industrial standards.

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41

Penger, Jörn, Ralf Conrad y Martin Blaser. "Stable Carbon Isotope Fractionation by Methylotrophic Methanogenic Archaea". Applied and Environmental Microbiology 78, n.º 21 (17 de agosto de 2012): 7596–602. http://dx.doi.org/10.1128/aem.01773-12.

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ABSTRACTIn natural environments methane is usually produced by aceticlastic and hydrogenotrophic methanogenic archaea. However, some methanogens can use C1compounds such as methanol as the substrate. To determine the contributions of individual substrates to methane production, the stable-isotope values of the substrates and the released methane are often used. Additional information can be obtained by using selective inhibitors (e.g., methyl fluoride, a selective inhibitor of acetoclastic methanogenesis). We studied stable carbon isotope fractionation during the conversion of methanol to methane inMethanosarcina acetivorans,Methanosarcina barkeri, andMethanolobus zinderiand generally found large fractionation factors (−83‰ to −72‰). We further tested whether methyl fluoride impairs methylotrophic methanogenesis. Our experiments showed that even though a slight inhibition occurred, the carbon isotope fractionation was not affected. Therefore, the production of isotopically light methane observed in the presence of methyl fluoride may be due to the strong fractionation by methylotrophic methanogens and not only by hydrogenotrophic methanogens as previously assumed.

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42

Campion, Robert, Glyn Morgan y Michael Samulak. "Some Durability Aspects of Thermoplastics for Oilfield Flexible Pipes". Engineering Plastics 5, n.º 6 (enero de 1997): 147823919700500. http://dx.doi.org/10.1177/147823919700500606.

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Some initial mechanical property, fatigue, high pressure (HP) methane permeation and explosive decompression data are reported for plasticized PVDF thermoplastics before and after various exposures in two fluids. The exposures were for different times and elevated temperatures, and were usually performed at 5000psi (345 bar). The fluids were a 97/3 methane/carbon-dioxide mixture saturated with water vapour, and 100% methanol, both of which induce some physical or physico-chemical changes in the material, but negligible chemical change. Thus measurements were made using reasonable simulations of fluids which could be met in oil production flexible pipe service. Effects of ‘extra’ plasticisation by absorbed gas, deplasticisation of actual plasticizer, and ageing, are shown for some combinations. Arrhenius-type plots for HP methane permeation, allowing predictions of rates at other temperatures, and showing hydrostatic compaction effects, have been obtained: HP methane permeation rate is reduced by prior exposure to the methane/carbon-dioxide gas, but is increased in the presence of methanol.

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43

Campion, Robert, Glyn Morgan y Michael Samulak. "Some Durability Aspects of Thermoplastics for Oilfield Flexible Pipes". Polymers and Polymer Composites 5, n.º 6 (septiembre de 1997): 451–58. http://dx.doi.org/10.1177/096739119700500606.

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Some initial mechanical property, fatigue, high pressure (HP) methane permeation and explosive decompression data are reported for plasticized PVDF thermoplastics before and after various exposures in two fluids. The exposures were for different times and elevated temperatures, and were usually performed at 5000psi (345 bar). The fluids were a 97/3 methane/carbon-dioxide mixture saturated with water vapour, and 100% methanol, both of which induce some physical or physico-chemical changes in the material, but negligible chemical change. Thus measurements were made using reasonable simulations of fluids which could be met in oil production flexible pipe service. Effects of ‘extra’ plasticisation by absorbed gas, deplasticisation of actual plasticizer, and ageing, are shown for some combinations. Arrhenius-type plots for HP methane permeation, allowing predictions of rates at other temperatures, and showing hydrostatic compaction effects, have been obtained: HP methane permeation rate is reduced by prior exposure to the methane/carbon-dioxide gas, but is increased in the presence of methanol.

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44

Fait, M. J. G., A. Ricci, M. Holena, J. Rabeah, M. M. Pohl, D. Linke y E. V. Kondratenko. "Understanding trends in methane oxidation to formaldehyde: statistical analysis of literature data and based hereon experiments". Catalysis Science & Technology 9, n.º 18 (2019): 5111–21. http://dx.doi.org/10.1039/c9cy01055f.

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A regression tree analysis on selective oxidation of methane to methanol/formaldehyde was applied to identify fundamentals affecting catalyst performance. The electronegativity correlates with methane activation energy and formaldehyde selectivity.

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45

Xin, Jia Ying, Jia Liang Jiang, Shuai Zhang, Chao Ze Yan, Ying Xin Zhang, Jing Dong y Chun Gu Xia. "Use of CAS Colorimetric Assays to Evaluate the Effect of Copper Ion on Methanobactin Production by Methylosinus trichosporium 3011". Advanced Materials Research 549 (julio de 2012): 50–53. http://dx.doi.org/10.4028/www.scientific.net/amr.549.50.

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Methanobactin (mb) is a small copper-binding chromopeptide produced by methanotrophs. In this paper, a quantitative assay method for the content of mb was developed. The mb produced by Methylosinus trichosporium 3011growth with methane and methanol as carbon sources were detected from the culture supernatants by the CAS colorimetric assay at wavelengths 605 nm. The aim of this study was to evaluate the effect of copper ion on mb production by methane-growth and methanol-growth Methylosinus trichosporium 3011. The results of our experiments prove that Methylosinus trichosporium 3011 is able to utilize methanol as sole source of carbon and energy to produce mb. Cells grown on both methane and methanol exhibited differences in the accumulations of mb which were dependent on the concentration of copper (Ⅱ) present in the growth medium. An increase in the concentration of copper (Ⅱ) in the growth medium decreased mb content in the supernatant solutions. However, the mb was shown to exhibit maximal concentration at 0.5µmol/L copper (Ⅱ) with methanol as carbon source in contrast to the mb from cells grown on methane which as maximum concentration at 0 µmol/L copper (Ⅱ).

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46

Lee, Bor-Jih, Shigeo Kitsukawa, Hidemoto Nakagawa, Shukuji Asakura y Kenzo Fukuda. "The Partial Oxidation of Methane to Methanol with Nitrite and Nitrate Melts". Zeitschrift für Naturforschung B 53, n.º 7 (1 de julio de 1998): 679–82. http://dx.doi.org/10.1515/znb-1998-0705.

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Abstract The effect of reduced oxygen species on the partial oxidation of methane to methanol was examined with nitrite melts. The experimental results support the suggestion that the formation of methanol or C2 compounds depends on different reduced oxygen species, as observed in our previous work using nitrate melts. It has been suggested that the partial oxidation of methane proceeds to CH3OH or C2 compounds via parallel pathways. This suggestion was verified by increasing the oxygen concentration to carry out the partial oxidation of methane in 25 mol% NaNCO3 -75 mol% KNO3 melts. A methanol selectivity of 8.2% and a methanol yield of 0.43% were observed with CH4/O2 = 15/1 at 575 °C, whereas with CH4/O2 = 7/1 methanol selectivity and yield increased to 23.7% and 1.1%, respectively. The results further confirm the contribution of the superoxide ion O2- on methanol formation.

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47

Kang, Jongkyu y Eun Duck Park. "Liquid-Phase Selective Oxidation of Methane to Methane Oxygenates". Catalysts 14, n.º 3 (24 de febrero de 2024): 167. http://dx.doi.org/10.3390/catal14030167.

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Methane is an abundant and relatively clean fossil fuel resource; therefore, its utilization as a chemical feedstock has a major impact on the chemical industry. However, its inert nature makes direct conversion into value-added products difficult under mild conditions. Compared to the gas-phase selective oxidation of methane, there have been several recent advances in the liquid-phase conversion of methane. This review categorizes the reports on the liquid-phase selective oxidation of methane according to the solvent and oxidant used. The advantages and disadvantages of each approach are discussed. High yields of methyl bisulfate as a methanol precursor can be achieved using SO3 in sulfuric acid; however, more attention should be paid to the separation process and overall economic analysis. However, the aqueous-phase selective oxidation of methane with in situ generated H2O2 is quite promising from an environmental point of view, provided that an economical reducing agent can be used. Based on the current state-of-the-art on this topic, directions for future research are proposed.

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48

Maia, Victória A., Julio Nandenha, Marlon H. Gonçalves, Rodrigo F. B. de Souza y Almir O. Neto. "Methane to Methanol Conversion Using Proton-Exchange Membrane Fuel Cells and PdAu/Antimony-Doped Tin Oxide Nanomaterials". Methane 2, n.º 3 (25 de junio de 2023): 252–64. http://dx.doi.org/10.3390/methane2030017.

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This study investigates the use of Au-doped Pd anodic electrocatalysts on ATO support for the conversion of methane to methanol. The study uses cyclic voltammetry, in situ Raman spectra, polarization curves, and FTIR analysis to determine the optimal composition of gold and palladium for enhancing the conversion process. The results demonstrate the potential for utilizing methane as a feedstock for producing sustainable energy sources. The Pd75Au25/ATO electrode exhibited the highest OCP value, and Pd50Au50/ATO had the highest methanol production value at a potential of 0.05 V. Therefore, it can be concluded that an optimal composition of gold and palladium exists to enhance the conversion of methane to methanol. The findings contribute to the development of efficient and sustainable energy sources, highlighting the importance of exploring alternative ways to produce methanol.

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49

Kudrik, Evgeny V., Pavel Afanasiev, Denis Bouchu, Jean-Marc M. Millet y Alexander B. Sorokin. "Diiron N-bridged species bearing phthalocyanine ligand catalyzes oxidation of methane, propane and benzene under mild conditions". Journal of Porphyrins and Phthalocyanines 12, n.º 10 (octubre de 2008): 1078–89. http://dx.doi.org/10.1142/s1088424608000431.

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Transformation of methane, the most abundant and the least reactive compound of natural gas to valuable products is one of the most difficult chemical problems of great practical importance. In Nature, methane monooxygenase enzymes transform methane to methanol in water under physiological conditions. However, chemical analogs for such a transformation are unknown. Here, we show the mild and efficient aqueous oxidation of methane by hydrogen peroxide, an ecologically and biologically relevant oxidant catalyzed by supported μ-nitrido diiron phthalocyanine dimer, (FePc t Bu 4)2 N . This bio-inspired complex containing a stable Fe – N – Fe motif catalyzes the oxidation of methane to methanol which is further transformed to formaldehyde and formic acid as is demonstrated using 13 CH 4 and 18 O labelling. (FePc t Bu 4)2 N - H 2O2 system shows a high activity in the oxidation of benzene to phenol which occurs via formation of benzene oxide and exhibits NIH shift typically accociated with biological oxidation. Mechanistic features of oxidation of methane and benzene as well as detected intermediate hydroperoxo- and high valent oxo diiron complexes support an O-atom transfer reaction mechanism relevant to bio-oxidation.

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50

Muhammad Ahsan y Edgar Luna. "Resource classification of coal bed methane and its contribution in energy transition and decarbonization path of oil and gas industry (A synopsis of CBM Life Cycle Analysis)". World Journal of Advanced Engineering Technology and Sciences 12, n.º 1 (30 de mayo de 2024): 001–7. http://dx.doi.org/10.30574/wjaets.2024.12.1.0156.

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World economies are becoming increasingly more dependent on energy and countries have a voracious appetite for energy therefore, the need for an abundant clean energy is becoming a necessity. Energy companies are challenging environmental costs of coal bed methane as with advancement of new technology the impact from production of coal bed methane can reduce and to a certain extent avoided or offset. Production of coal bed methane results in changes to the land, to surface water and to ground water systems. Carbon quantification is required to understand, monitor and manage these changes. Previous life cycle analysis for this resource class has lack of process design details because of which there is a knowledge gap in understanding of emission profile of coal bed methane’s production. The objective of this study is to add value and reduce the scientific gap with respect to the production techniques of coal bed methane and its environmental impact. Removal of water continuously from coal seams depletes ground water and may eventually lower surface water flows (streams and rivers). It can also change the flow of groundwater drawing fresh water into the coal seams. To better understand this phenomenon the work establishes the Coal Bed Methane production foundation by in depth understanding of · Coal Bed Methane reservoir types; · Coal Bed Methane depositional environment, generation, and geological distributions; · Coal Bed Methane resource energy supply methods by understanding its construction, production and processing. The study then uses Life Cycle Assessment approach and understands previous emission numbers of Coal Bed Methane’s resource development. The work does systematic analysis and summarizes the previously published Life Cycle Analysis to understand further the potential environmental impacts of resource development of Coal Bed Methane. This will help energy companies to understand the field development, production, and operations of coal bed methane’s resource in terms of carbon numbers thereby optimizing the operations through carbon management thus reducing the potential impacts.

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