Journal ArticleDOI
Measurement of Clathrate Hydrates via Raman Spectroscopy
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Raman spectra of clathrate hydrate guest molecules are presented for three known structures (I (sI), II (sII), and H (sH)) in the following systems:Abstract:
Raman spectra of clathrate hydrate guest molecules are presented for three known structures (I (sI), II (sII), and H (sH)) in the following systems: CH4 (sI), CO2 (sI), C3H8 (sII), CH4 + CO2 (sI), CD4 + C3H8 (sII), CH4 + N2 (sI), CH4 + THF-d8 (sII), and CH4 + C7D14 (sH). Relative occupancy of CH4 in the large and small cavities of sI were determined by deconvoluting the ν1 symmetric bands, resulting in hydration numbers of 6.04 ± 0.03. The frequency of the ν1 bands for CH4 in structures I, II, and H differ statistically, so that Raman spectroscopy is a potential tool to identify hydrate crystal structure. Hydrate guest compositions were also measured for two vapor compositions of the CH4 + CO2 system, and they compared favorably with predictions. The large cavities were measured to be almost fully occupied by CH4 and CO2, whereas only a small fraction of the small cavities are occupied by CH4. No CO2 was found in the small cavities. Hydration numbers from 7.27 to 7.45 were calculated for the mixed hydrate.read more
Citations
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Co-adsorption and separation of CO2-CH4 mixtures in the highly flexible MIL-53(Cr) MOF.
Lomig Hamon,Philip L. Llewellyn,Thomas Devic,Aziz Ghoufi,Guillaume Clet,Vincent Guillerm,Gerhard D. Pirngruber,Guillaume Maurin,Christian Serre,Gordon Driver,Wouter van Beek,Elsa Jolimaitre,Alexandre Vimont,Marco Daturi,Gérard Férey +14 more
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References
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Journal ArticleDOI
Compositions, enthalpies of dissociation, and heat capacities in the range 85 to 270 K for clathrate hydrates of methane, ethane, and propane, and enthalpy of dissociation of isobutane hydrate, as determined by a heat-flow calorimeter
TL;DR: In this article, the Tian-Calvet heat-flow calorimeter was used to measure the enthalpy of dissociation for clathrate hydrates of methane, ethane, and propane.
Book ChapterDOI
Raman Scattering Cross Sections in Gases and Liquids
H. W. Schrötter,H. W. Klöckner +1 more
TL;DR: In this article, the photographic technique of recording high-resolution Raman spectra of gases allows the precise measurement of wavenumber shifts and the accurate determination of molecular constants derived therefrom.
Journal ArticleDOI
Occurrence of methane hydrate in saturated and unsaturated solutions of sodium chloride and water in dependence of temperature and pressure
TL;DR: In this paper, experimental results of the formation of methane hydrate in dependence of temperature and pressure in unsaturated solutions of NaCl in water were presented in a temperature range from 261.85 to 285.98 K and pressure up to 11.0 MPa.
Journal ArticleDOI
Low-temperature cross-polarization/magic angle spinning carbon-13 NMR of solid methane hydrates: structure, cage occupancy, and hydration number
TL;DR: In this article, the NMR spectra of methane trapped in solid type I hydrate and in a mixed methane/propane type II hydrate were studied at -80/sup 0/C under cross-polarization and magic angle spinning conditions.
Journal ArticleDOI
The ability of small molecules to form clathrate hydrates of structure II
TL;DR: In this article, it was shown that the two smallest molecules which form clathrate hydrates (argon and krypton) do so in the structure II modification, which supports a suggestion of Holder and Manganiello4.