Thermodynamic and Raman spectroscopic studies on hydrogen+tetra-n-butyl ammonium fluoride semi-clathrate hydrates

Thermodynamic Properties of Hydrogen + Tetra-n-Butyl Ammonium Bromide Semi-Clathrate Hydrate

“…The characteristic slope change (dp/dT) derived from the structural transition on the three-phase equilibrium curve exists at ∼95 MPa and 292 K only in the case of x = 0.020. The phase behavior and structural transition of H 2 + TBAB semi-clathrate hydrate system are closely similar to those of H 2 + TBAF semi-clathrate hydrate system [16] Figure 2: Raman spectra originated in TBAB, H 2 , and host lattice of water for the H 2 + TBAB semi-clathrate hydrate at x = 0.020. Closed inverted-triangle represents the peak used for the normalization of H 2 vibration peak.…”

“…hydrate is much severer (the transition pressure is ∼90 MPa higher) than that of H 2 + TBAF semi-clathrate hydrate [16].…”

“…The high-pressure optical cell was the same as previous one [16] except for the window material. The maximum working pressure of high-pressure optical cell was 400 MPa.…”

“…In our previous study, the cage occupancy of H 2 has been investigated by use of phase equilibrium measurements and Raman spectroscopic analyses for two structures of H 2 + TBAB semiclathrate hydrates up to 15 MPa [8]. Most recently, we have reported that hydrogen-induced structural transition from cubic to another structure (probably tetragonal) occurs on H 2 + tetra-n-butyl ammonium fluoride (hereafter, TBAF) semi-clathrate hydrate [16]. The storage amount of H 2 in H 2 + TBAF semi-clathrate hydrate drastically increases with the structural transition.…”

From Zeolite to Host-Guest Nanocomposite Materials

“…So that, these types of ionic clathrate hydrates are also called "semi-clathrate" because some cages are partially broken in order to encage the large cations [150]. Recently, ionic clathrate hydrates have received increased attention arising from their potential applications in various fields, including solid electrolytes, gas separation, and gas storage [151][152][153]. Kamata et al [154,155] examined the ability of the (nBu) 4 NBr clathrate hydrate to separate the gas mixtures.…”