Table of Contents
Journal of Thermodynamics
Volume 2010 (2010), Article ID 170819, 5 pages
http://dx.doi.org/10.1155/2010/170819
Research Article

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

Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan

Received 5 April 2009; Accepted 17 September 2009

Academic Editor: Jae Lee

Copyright © 2010 Shunsuke Hashimoto et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Thermodynamic stability and hydrogen occupancy on the hydrogen + tetra- -butyl ammonium bromide semi-clathrate hydrate were investigated by means of Raman spectroscopic and phase equilibrium measurements under the three-phase equilibrium condition. The structure of mixed gas hydrates changes from tetragonal to another structure around 95 MPa and 292 K depending on surrounding hydrogen fugacity. The occupied amount of hydrogen in the semi-clathrate hydrate increases significantly associated with the structural transition. Tetra- -butyl ammonium bromide semi-clathrate hydrates can absorb hydrogen molecules by a pressure-swing without destroying the hydrogen bonds of hydrate cages at 15 MPa or over.