Polarization response of clathrate hydrates capsulated with guest molecules

2016 ◽  
Vol 144 (20) ◽  
pp. 204308 ◽  
Author(s):  
Qun Zeng ◽  
Jinshan Li ◽  
Hui Huang ◽  
Xinqin Wang ◽  
Mingli Yang
Keyword(s):  
Clathrate Hydrates ◽  
Guest Molecules ◽  
Polarization Response

scholarly journals Characterization of free radicals in clathrate hydrates of pyrrole, thiophene, and isoxazole by muon spin spectroscopy

2018 ◽  
Vol 96 (2) ◽  
pp. 217-225 ◽  
Author(s):  
Mina Mozafari ◽  
Lalangi Chandrasena ◽  
Iain McKenzie ◽  
Kerim Samedov ◽  
Paul W. Percival
Keyword(s):  
Free Radicals ◽  
Muon Spin ◽  
Carbon Dioxide Sequestration ◽  
Clathrate Hydrates ◽  
Pure Liquid ◽  
Guest Molecules ◽  
Hyperfine Constants ◽  
Potential Applications ◽  
Muon Spin Spectroscopy

Gas hydrates have long been of interest to the petrochemical industry, but there has been growing interest in potential applications for carbon dioxide sequestration and hydrogen storage. This has prompted many fundamental studies of structure and host–guest interactions, but there has been relatively little investigation of chemical reactions of the guest molecules. In previous work, we have shown that it is possible to use muon spin spectroscopy to characterize H atom like muonium and muoniated free radicals formed in clathrate hydrates. Muonium (Mu) forms in clathrate hydrates of cyclopentane and tetrahydrofuran, whereas furan and its dihydro derivatives form radicals. The current work extends studies to clathrates hydrates of other five-membered heterocycles: thiophene, pyrrole, and isoxazole. All form structure II hydrates. In addition to the clathrates, pure liquid samples of the heterocycles were studied to aid in the assignment of radical signals and for comparison with the enclathrated radicals. Similar to furan, two distinct radicals are formed when Mu reacts with thiophene and pyrrole. However, only one muoniated radical was detected from isoxazole. Muon, proton, and nitrogen hyperfine constants were determined and compared with values predicted by DFT calculations to aid the structure assignments. The results show that Mu adds preferentially to the carbon adjacent to the heteroatom in thiophene and pyrrole and to the carbon adjacent to oxygen in isoxazole. The same radicals are formed in clathrates, but the spectra have broader signals, suggesting slower tumbling. Furthermore, additional signals in the avoided level-crossing spectra indicate anisotropy consistent with restricted motion of the radicals in the clathrate cages.

scholarly journals Effect of temperature and large guest molecules on the C–H symmetric stretching vibrational frequencies of methane in structure H and I clathrate hydrates

RSC Advances ◽  
2020 ◽  
Vol 10 (30) ◽  
pp. 17473-17478
Author(s):  
Go Fuseya ◽  
Satoshi Takeya ◽  
Akihiro Hachikubo
Keyword(s):  
Temperature Effect ◽  
Vibrational Frequencies ◽  
Clathrate Hydrates ◽  
Effect Of Temperature ◽  
Guest Molecules

Temperature effect on C–H symmetric stretching frequencies of CH4 in water cages of sI and sH clathrate hydrates were clarified.

Nitrogen and oxygen guest molecules in clathrate hydrates: different sites revealed by Raman spectroscopy

1997 ◽  
Vol 28 (9) ◽  
pp. 711-715 ◽  
Author(s):  
B. Champagnon ◽  
G. Panczer ◽  
B. Chazallon ◽  
L. Arnaud ◽  
P. Duval ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Clathrate Hydrates ◽  
Guest Molecules

Role of Guest Molecules in the Mechanical Properties of Clathrate Hydrates

2018 ◽  
Vol 18 (11) ◽  
pp. 6729-6741 ◽  
Author(s):  
Qiao Shi ◽  
Pinqiang Cao ◽  
Zhengde Han ◽  
Fulong Ning ◽  
Hao Gong ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Clathrate Hydrates ◽  
Guest Molecules

scholarly journals Retraction: Effect of temperature and large guest molecules on the C–H symmetric stretching vibrational frequencies of methane in structure H and I clathrate hydrates

RSC Advances ◽  
2020 ◽  
Vol 10 (29) ◽  
pp. 16904-16904
Author(s):  
Go Fuseya ◽  
Satoshi Takeya ◽  
Akihiro Hachikubo
Keyword(s):  
Vibrational Frequencies ◽  
Clathrate Hydrates ◽  
Effect Of Temperature ◽  
Guest Molecules

Retraction of ‘Effect of temperature and large guest molecules on the C–H symmetric stretching vibrational frequencies of methane in structure H and I clathrate hydrates’ by Akihiro Hachikubo et al., RSC Adv., 2018, 8, 3237–3242, DOI: 10.1039/c7ra12334e.

On the thermodynamic stability of clathrate hydrates

2003 ◽  
Vol 81 (1-2) ◽  
pp. 55-60 ◽  
Author(s):  
H Tanaka
Keyword(s):  
Free Energy ◽  
Thermodynamic Stability ◽  
Vibrational Frequency ◽  
Host Lattice ◽  
Clathrate Hydrates ◽  
Total Free Energy ◽  
Guest Molecules ◽  
Free Energy Of Formation ◽  
Entropic Contribution ◽  
Energy Of Formation

The thermodynamic stability of clathrate hydrates is investigated by theoretically examining the free energy of formation of clathrate hydrates encaging propane and argon. The total free energy is divided into several contributions: the interaction between water and guest molecules, the entropic contribution arising from the combinations of cage occupancy, and the free energy due to intermolecular vibrations. The method introduced here removes some of the assumptions of the van der Waals and Platteeuw theory. It is shown that the shift of the vibrational frequency of the host lattice destabilizes the clathrate hydrates thermodynamically. PACS No.: 61.50Ah

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