Activation Energy of Methyl Radical Decay in Methane Hydrate

Takeya, Kei; Nango, Kouhei; Sugahara, Takeshi; Ohgaki, Kazunari; Tani, Atsushi

doi:10.1021/jp054028e

Cited by 42 publications

(43 citation statements)

References 6 publications

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“…[22,23] Assuming the presence of such a super-cooled liquid water phase, it might cover (wet) surfaces of decomposing hydrates, and some hydrate crystals might be captured in the water medium during crystallization.…”

Section: à3mentioning

confidence: 99%

Morphological and Compositional Characterization of Self‐Preserved Gas Hydrates by Low‐Vacuum Scanning Electron Microscopy

et al. 2011

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Unequal interactions: A backscattering electron microscopy study reveals that some Kr hydrates can be trapped in ice products during dissociation (see image) whereas no clear evidence of such a phenomenon is found for Ar samples. Also, the texture of ice from Ar‐hydrate decomposition is more cohesive than that observed for Kr samples. The different dissociation behavior between the two systems may be attributed to differences in the interaction between gas and water molecules.

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Section: à3mentioning

confidence: 99%

Morphological and Compositional Characterization of Self‐Preserved Gas Hydrates by Low‐Vacuum Scanning Electron Microscopy

et al. 2011

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“…The study of controlled reactions in clathrate hydrates has led to the suggestion that they be used as "nano-reactors". 7 Free radicals can be created in clathrate hydrates by photolysis of either the guest 8 or the host water molecules, 9 but most studies employ γ-irradiation, [10][11][12][13][14][15][16] and thence reaction of guest molecules with the transient products (H, OH, e -) of water radiolysis. At low temperature hydrogen atoms (H or D) can be detected by electron spin resonance (ESR).…”

Section: Introductionmentioning

confidence: 99%

Characterization of Free Radicals in Clathrate Hydrates of Furan, 2,3-Dihydrofuran, and 2,5-Dihydrofuran by Muon Spin Spectroscopy

et al. 2016

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In addition to their importance as abundant hydrocarbon deposits in nature, clathrate hydrates are being studied as potential media for hydrogen and carbon dioxide storage, and as "nano-reactors" for small molecules. However, little is known about the behaviour of reactive species in such materials. We have employed muon spin spectroscopy to characterize various organic free radicals which reside as isolated guests in structure II clathrates. The radicals are formed by reaction of atomic muonium (Mu) with the guest molecules: furan and two isomeric dihydrofurans. Muonium is essentially a light isotope of hydrogen, and adds to unsaturated molecules in the same manner as H. We have determined muon and proton hyperfine coupling constants for the muoniated radicals formed in the clathrates and also in neat liquids at the same temperature. DFT calculations were used to guide the spectral assignments and distinguish between competing radical products for Mu addition to furan and 2,3-dihydrofuran. Relative signal amplitudes provide yields and thus the relative reactivities of the C4 and C5 addition sites in these molecules. Spectral features, hyperfine constants and reactivities all indicate that the radicals do not tumble freely in the clathrate cages in the same way that they do in liquids.

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“…We have reported the thermal stabilities of methyl, ethyl, and propyl radicals in the γ-ray-irradiated simple methane [1,2], ethane [3], and propane [4] hydrate systems. The radicals in other clathrate hydrates have been investigated [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Intermolecular Hydrogen Transfer in Isobutane Hydrate

et al. 2012

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Electron spin resonance (ESR) spectra of butyl radicals induced with γ-ray irradiation in the simple isobutane (2-methylpropane) hydrate (prepared with deuterated water) were investigated. Isothermal annealing results of the γ-ray-irradiated isobutane hydrate reveal that the isobutyl radical in a large cage withdraws a hydrogen atom from the isobutane molecule through shared hexagonal-faces of adjacent large cages. During this "hydrogen picking" process, the isobutyl radical is apparently transformed into a tert-butyl radical, while the sum of isobutyl and tert-butyl radicals remains constant. The apparent transformation from isobutyl to tert-butyl radicals is an irreversible first-order reaction and the activation energy was estimated to be 35 ± 3 kJ/mol, which was in agreement with the activation energy (39 ± 5 kJ/mol) of hydrogen picking in the γ-ray-irradiated propane hydrate with deuterated water.

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Activation Energy of Methyl Radical Decay in Methane Hydrate

Cited by 42 publications

References 6 publications

Morphological and Compositional Characterization of Self‐Preserved Gas Hydrates by Low‐Vacuum Scanning Electron Microscopy

Morphological and Compositional Characterization of Self‐Preserved Gas Hydrates by Low‐Vacuum Scanning Electron Microscopy

Characterization of Free Radicals in Clathrate Hydrates of Furan, 2,3-Dihydrofuran, and 2,5-Dihydrofuran by Muon Spin Spectroscopy

Intermolecular Hydrogen Transfer in Isobutane Hydrate

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