Oxidation Of Dimethyl Ether Research Articles

A comparative study of the complete oxidation of dimethyl ether on supported group VIII metals

In the study of the interaction of dimethyl ether with alumina-supported platinum metals by means of infrared spectroscopy, methoxy species bonded to the alumina and CO adsorbed on the metals have been detected. The complete oxidation of dimethyl ether in a flow system sets in above 400 K and proceeded to 100% conversion at ~673 K. No or only very slight deactivation was observed in 5 h. The specific activity order of the catalysts is: Ru>Pt>Ir>Pd>Rh.

Chemical kinetic study of dimethylether oxidation in a jet stirred reactor from 1 to 10 ATM: Experiments and kinetic modeling

The oxidation of dimethyl ether (DME) has been studied in a jet-stirred reactor (JSR). The experiments cover a wide range of conditions: 1–10 atm, 0.2≤≤2.0, 800–1300 K. Concentration profiles of reactants, internediates, and products of the oxidation of DME were measured in a fused silica JSR by low-pressure, sonic-probe sampling and off-line gas chromatography analyses. These results represent the first detailed kinetic study of DME oxidation in a reactor. They demonstrate that the oxidation of DME does not yield higher molecular weight compounds. A numerical model consisting of a detailed kinetic-reaction mechanism with 286 reactions (most of them reversible) among 43 species describes DME oxidation in a JSR. A generally good agreement between the data and the model was observed. The kinetic modeling is used to interpret the data.

Dimethyl Ether Oxidation: Kinetics and Mechanism of the CH3OCH2 + O2 Reaction at 296 K and 0.38−940 Torr Total Pressure

Dimethyl Ether Oxidation: Kinetics and Mechanism of the CH₃OCH₂ + O₂ Reaction at 296 K and 0.38−940 Torr Total Pressure

Oxidation of methyl fluoride and dimethyl ether by ammonia monooxygenase in Nitrosomonas europaea

Methyl fluoride and dimethyl ether were previously identified as inhibitors of ammonia oxidation and N2O production in autotrophic nitrifying bacteria. We demonstrate that methyl fluoride and dimethyl ether are substrates for ammonia monooxygenase and are converted to formaldehyde and a mixture of methanol and formaldehyde, respectively.

The atmospheric chemistry of Oxygenated fuel additives: t‐Butyl alcohol, dimethyl ether, and methylt‐butyl ether

AbstractThe mechanisms for the Cl‐initiated and OH‐initiated atmospheric oxidation of t‐butyl alcohol (TBA), methyl t‐butyl ether (MTBE), and dimethyl ether (DME) have been determined. For TBA the only products observed are equimolar amounts of H2CO and acetone, and its atmospheric oxidation can be represented by (7), equation image The mechanism for the atmospheric oxidation of DME is also straight forward, with the only observable product being methyl formate, equation image The mechanism for the atmospheric oxidation of MTBE is more complex, with observable products being t‐butyl formate (TBF) and H2CO. Evidence is presented also for the formation of 2‐methoxy‐2‐methyl propanal (MMP), which is highly reactive and presumably oxidized to products. The atmospheric oxidation of MTBE can be represented by (9) and (10), equation image equation image In terms of atmospheric reactivity, DME, TBA, and MTBE all compare favorably with methanol. In terms of rate of reaction in the atmosphere, DME, MTBE, and TBA are 1.4, 0.40, and 0.28 times as reactive as CH3OH towards OH on a per carbon basis. With regard tochemistry, atmospheric oxidation of CH3OH yields highly reactive H2CO as the sole carbon‐containing product. In contrast, only 25% of the carbon in TBA is converted to H2CO, with the balance yielding unreactive acetone. For DME, all the carbon is converted to methyl formate which is unreactive. Finally, for MTBE, 60% is converted to unreactive TBF while the remaining 40% produces highly reactive MMP.Final assessment of the impact of these materials on the atmospheric reactivity of vehicle emissions requires the determination of their emissions rates under realistic operating conditions.

THE ELUCIDATION OF THE KINETICS AND MECHANISMS OF THE CATALYTIC OXIDATION OF TRACE AMOUNTS OF DIMETHYL ETHER IN OXYGEN BY TRANSIENT PHENOMENA

Thermal desorption experiments with different heating schemes were used to study the kinetics and mechanisms of the catalytic oxidation of dimethyl ether (DME) on supported Pt catalysts. The experimental apparatuses were fully automated by using a microcomputer control system. This made possible direct evaluations of several key kinetic parameters as well as long-term evaluations of the catalysts. The oxidation of DME catalyzed by Pt/SiO2-Al2O3, catalyst has been shown to involve the chemisorption of DME on the support and the chemisorption of oxygen on Pt metal sites. The surface reaction between chemisorbed DME and oxygen was found to be the rate-determining step under the experimental conditions investigated. The proposed reaction mechanism using the kinetic parameters estimated from the thermal desorption experiments predicts the experimental results very well. Acetylene was found to have a promotional effect for the reaction. It is believed that carbon from acetylene plays a key role in this reaction...

Oxidation of Dimethyl Ether, Methyl Formate and Bromomethane by Methylococcus capsulatus (Bath)

Suspensions of Methylococcus capsulatus strain Bath oxidized dimethyl ether, methyl formate and bromomethane. The rate of disappearance of dimethyl ether was enhanced up to 11-fold in the presence of co-substrates such as formaldehyde. Dimethyl ether was oxidized by the purified methane mono-oxygenase from M. capsulatus (Bath) to give various amounts of methanol and formaldehyde. As M. capsulatus (Bath) cannot grow on dimethyl ether it was concluded that this ether is a non-growth substrate which can be fortuitously oxidized. Possible reasons for the lack of growth on dimethyl ether are discussed. Methyl formate and bromomethane were oxidized by the purified methane mono-oxygenase to yield equal stoicheiometric amounts of formaldehyde and formic acid, and formaldehyde alone, respectively. Methylococcus capsulatus (Bath) grew on methyl formate but not on bromomethane and it was concluded that the latter is a non-growth substrate which can be fortuitously oxidized. Preliminary evidence is presented for carbon assimilation during the oxidation of bromomethane.

Photolytic oxidation of ethylene glycol dimethyl ether and related compounds by aqueous hypochlorite

The photochemical oxidation of ethylene glycol dimethyl ether (EDE) and related substrates by aqueous sodium hypochlorite has been studied. In the presence of a large excess of hypochlorite, EDE is completely photolysed to give CO2 and H2O. On the other hand, irradiation of an equimolar mixture of the substrate and aqueous hypochlorite gives CH3OH, HCHO, HCOOH, CH3OCH2CH2OH, CH3OCH2CHO, CH3COOH, and a trace of CHCl3, which is the only chlorine-containing product. The photo-oxidation of the other substrates gives analogous products.

Study of photolytic oxidation and chlorination reactions of dimethyl ether and chlorine in ambient air

Study of photolytic oxidation and chlorination reactions of dimethyl ether and chlorine in ambient air

ChemInform Abstract: CHEMICAL STUDIES OF THE PROTEACEAE. VIII. THE CONVERSION OF GREVILLOL INTO RAPANONE AND EXPERIMENTS ON THE SYNTHESIS OF ARDISIAQUINONE A

AbstractGrevilloldimethyläther (I) wird zu dem Chinon (II) oxidiert, dessen Acetoxylierung nach Thiele‐Winter das aromatische Triacetat (III) liefert.

Inhibition of dimethyl ether and methane oxidation in Methylococcus capsulatus and Methylosinus trichosporium.

Metal-chelating or -binding agents inhibited the oxidation of dimethyl ether and methane, but not methanol, by cell suspensions of Methylococcus capsulatus and Methylosinus trichosporium. Evidence suggests that the involvement of metal-containing enzymatic systems in the initial step of oxidation of dimethyl ether and methane.

Chemical studies of the Proteaceae. VIII. The conversion of grevillol into rapanone and experiments on the synthesis of ardisiaquinone A

Oxidation of grevillol dimethyl ether gave 2-methoxy-6-tridecyl-1,4-benzoquinone which on Thiele-Winter acetoxylation afforded the triacetate of 5-methoxy-3-tridecylbenzene-1,2,4-triol. Hydrolysisfollowed by oxidation and demethylation then yielded rapanone.By the application of a known reaction sequence involving the Stevens rearrangement, dodec-6-ynedioic acid was converted into 5,5'-(hexadec-8-yne-1,16-diyl)diresorcinol tetramethyl ether which was similarly oxidized to the related diquinone. This substance could not be converted into ardisiaquinone A because Thiele-Winter acetoxylation was accompanied by attack on the triple bond.However, 5,5'-(hexadecane-l,l6-diyl)diresorcinol dimethyl ether by successive oxidation, acetoxylation, hydrolysis and oxidation gave dihydroardisiaquinone A.

ジメチルエーテルの酸化反応速度

ジメチルエーテルの酸化反応速度

Colouring matters of Australian Plants. V. Haemocorin: The chemistry of the Aglycone

Oxidation of the aglycone dimethyl ether B gives a cyclic anhydride isomeric with that previously obtained from dimethyl ether A. The chemical properties and absorption spectra of the two anhydrides and their derivatives suggest that they are dimethoxyphenylnaphthalic anhydrides with the methoxyl groups attached to the naphthalene ring system. Further degradation of the anhydrides eventually gives diphenyl-2,3,4-tricarboxylic acid. This is proved by decarboxylation to diphenyl and by the formation of an anilide phenylimide identical with a synthetic specimen. These results indicate that the aglycone is a dihydroxymethoxyphenylperinaphthenone, and further support is given by a study of model hydroxyperinaphthenones.