Progress in the partial oxidation of methane to methanol and formaldehyde

Brown, Michael; Parkyns, N.D.

doi:10.1016/0920-5861(91)80056-f

Cited by 180 publications

(92 citation statements)

References 45 publications

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“…[1,10] Oxidation also plays an important role in many industrial processes such as the conversion of methanol to formaldehyde. [16][17][18] Although ozone is a good oxidizer, direct exposure of deionized water to plasma, which contains not only ozone but also charged species, reactive oxygen species, and radicals, [19] creates a much stronger oxidizer than ozone. [20][21][22][23] It has been reported that water treated by various plasma discharges becomes acidic, [9][10][11][20][21][22][23][24] which leads to antimicrobial effects.…”

mentioning

confidence: 99%

Retraction: Plasma Acid: Water Treated by Dielectric Barrier Discharge

Shainsky

Dobrynin

Ercan

et al. 2012

Plasma Processes & Polymers

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It is demonstrated that direct exposure of deionized water to a dielectric barrier discharge (DBD) plasma creates an acid (pH % 2) and is in fact, a strong oxidizer (providing, e.g., peroxidation of a cell membrane). This study addresses the question: which acid is created in water by plasma treatment. Two major possibilities are considered: nitric/nitrous acid and an acid which consist of a hydrogen cation (H þ ) and a superoxide anion (O À 2 ), which, for the lack of a better term, we call plasma acid. The presence of nitric/nitrous acid in the water after plasma treatment in air is confirmed, although the observed pH % 2 cannot be completely explained by the production of nitric acid. Moreover, experiments with oxygen-plasma treatment of water also lead to high acidity, without production of nitrogen based acids at all. Therefore, O À 2 , the conjugate base of the plasma acid, is at least partially responsible for both lowering of the pH and the increase in the oxidizing power of the solution. Experiments indicate that peroxides such as H 2 O 2 and O À 2 , together with an acidic environment are likely to be responsible for the oxidation properties of the plasma treated water. This plasma acid remains stable for at least a day, depending on the gas where plasma is generated, but the effect is temporal. Existence of a temporal and stable oxidizer created using the plasma treatment of pure water not only raises interesting scientific questions and possibilities, but is also likely to provide many applications in situations where direct plasma treatment may be difficult to achieve. Plasma Process. Polym. 2012,

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confidence: 99%

Retraction: Plasma Acid: Water Treated by Dielectric Barrier Discharge

Shainsky

Dobrynin

Ercan

et al. 2012

Plasma Processes & Polymers

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“…isoprene), or another trace gas having comparable mixing ratio to methanol was to produce formaldehyde upon contact with the catalyst, methanol quantification could become problematic. Although a variety of studies have reported on the conversion of methane to methanol and formaldehyde using supported ferric molybdate catalysts at temperatures around 400-500 • C and pressures from 1-60 bar (Brown et al, 1991;Chun and Anthony, 1993;Chellappa and Viswanath, 1995), there are no reports describing methane conversion to formaldehyde at temperatures below 400 • C. In studies where conversion is observed, catalyst surface areas were up to 50 times higher than those of the catalyst used here. The only literature we could find describing alkene reactions using a catalyst similar to that used in this work (ethene; Martin et al, 1993) did not report formaldehyde production.…”

Section: Interference Studiesmentioning

confidence: 87%

Atmospheric methanol measurement using selective catalytic methanol to formaldehyde conversion

et al. 2005

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Abstract.A novel atmospheric methanol measurement technique, employing selective gas-phase catalytic conversion of methanol to formaldehyde followed by detection of the formaldehyde product, has been developed and tested. The effects of temperature, gas flow rate, gas composition, reactor-bed length, and reactor-bed composition on the methanol conversion efficiency of a molybdenum-rich, ironmolybdate catalyst [Mo-Fe-O] were studied. Best results were achieved using a 1:4 mixture (w/w) of the catalyst in quartz sand. Optimal methanol to formaldehyde conversion (>95% efficiency) occurred at a catalyst housing temperature of 345 • C and an estimated sample-air/catalyst contact time of <0.2 seconds. Potential interferences arising from conversion of methane and a number of common volatile organic compounds (VOC) to formaldehyde were found to be negligible under most atmospheric conditions and catalyst housing temperatures. Using the new technique, atmospheric measurements of methanol were made at the University of Bremen campus from 1 to 15 July 2004. Methanol mixing ratios ranged from 1 to 5 ppb with distinct maxima at night. Formaldehyde mixing ratios, obtained in conjunction with methanol by periodically bypassing the catalytic converter, ranged from 0.2 to 1.6 ppb with maxima during midday. These results suggest that selective, catalytic methanol to formaldehyde conversion, coupled with existing formaldehyde measurement instrumentation, is an inexpensive and effective means for monitoring atmospheric methanol.

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“…(2) Selective Partial Oxidation of Methane Oxidative coupling of methane proceeds via intermediate methyl radical, which is formed through oxidation of methane. Therefore, formation of methanol or formaldehyde has been investigated by suppressing and controlling this oxidation step 13) . Ethylene, which is formed during oxidative coupling, is useful as a raw material for polymer formation, but methanol and formaldehyde are also useful materials for petrochemistry and other applications.…”

Section: Direct Conversion Of Methanementioning

confidence: 99%

Methane Conversion Assisted by Plasma or Electric Field

Oshima

Sekine

2013

J. Jpn. Petrol. Inst.

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Direct conversion of methane to other valuable products such as ethylene, methanol, benzene, carbon, hydrogen, and syngas has been widely investigated. Such conversion requires high temperatures because of the strong C-H bond in CH4, and such high-temperature reactions present various problems: sequential reaction to decrease the selectivity to target products, need for multiple heat exchangers to use or recover high-temperature waste heat, materials that are stable at high temperatures, etc. To solve these problems, several trials have been undertaken to lower reaction temperatures using plasma, Non-Faradaic Electrochemical Modification of Catalytic Activity (NEMCA), and electric fields. This review describes recent trends in methane conversion, and describes our methods to lower the reaction temperature.

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Progress in the partial oxidation of methane to methanol and formaldehyde

Cited by 180 publications

References 45 publications

Retraction: Plasma Acid: Water Treated by Dielectric Barrier Discharge

Retraction: Plasma Acid: Water Treated by Dielectric Barrier Discharge

Atmospheric methanol measurement using selective catalytic methanol to formaldehyde conversion

Methane Conversion Assisted by Plasma or Electric Field

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