Structure
H (sH) Clathrate Hydrate with New Large
Molecule Guest Substances
Yusuke Jin
Masato Kida
Jiro Nagao
10.1021/jp403430z.s001
https://acs.figshare.com/articles/journal_contribution/Structure_H_sH_Clathrate_Hydrate_with_New_Large_Molecule_Guest_Substances/2353345
This study characterized new structure
H (sH) clathrate hydrates
with bromide large-molecule guest substances (LMGSs) bromocyclopentane
(BrCP) and bromocyclohexane (BrCH), using powder X-ray diffraction
(PXRD) and Raman spectroscopy. The lattice parameters of sH hydrates
with (CH<sub>4</sub> + BrCP) and (CH<sub>4</sub> + BrCH) were determined
from their PXRD profiles. On the basis of their Raman spectra, the
M-cage to S-cage occupancy ratio (4<sup>3</sup>5<sup>6</sup>6<sup>3</sup> and 5<sup>12</sup> cages, respectively), θ<sub>M</sub>/θ<sub>S</sub>, was estimated to be approximately 1.3, and
the Raman shift of the symmetric C–H vibrational modes of CH<sub>4</sub> in S- and M-cages was 2911.1 and 2909.1 cm<sup>–1</sup>, respectively. The phase-equilibrium conditions of sH hydrates with
(CH<sub>4</sub> + BrCP) and (CH<sub>4</sub> + BrCH) were determined
by an isochoric method. A comparison between the equilibria of sH
hydrates with BrCP and BrCH and those with other typical nonpolar
and polar LMGSs (methylcyclopentane, MCP; methylcyclohexane, MCH;
neohexane, NH; and <i>tert</i>-butyl methyl ether, TBME)
at the same temperature revealed that the equilibrium pressure increased
in the order NH < MCH < BrCH < TBME ∼ MCP < BrCP.
The phase stabilities of sH hydrates can be determined by not only
molecular geometry but also their polar properties, which affect guest–host
interactions.
2013-11-14 00:00:00
Raman
sH hydrates
NH
TBME
BrCP
BrCH
CH 4
LMGS
PXRD
Molecule Guest SubstancesThis study
MCH
MCP