Phase Equilibria and Dissociation Enthalpies of Tri-n-butylphosphine Oxide Semiclathrate Hydrates Incorporated with CH4, CO2, and H2

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• 作者：Jong-Ho Cha ; Eun Sung Kim ; Ki Sun Lee ; Jeong Won Kang ; Jeong Won Kang ; Ki-Sub Kim
• 刊名：Journal of Chemical & Engineering Data
• 出版年：2013
• 出版时间：December 12, 2013
• 年：2013
• 卷：58
• 期：12
• 页码：3494-3498
• 全文大小：232K
• 年卷期：v.58,no.12(December 12, 2013)
• ISSN：1520-5134

文摘

We investigated the phase equilibrium boundary of tri-n-butylphosphine oxide (TBPO) semiclathrate hydrates incorporated with CH₄, CO₂, and H₂. TBPO aqueous solutions with a molality (m) of (1.61 and 1.98) mol路kg^鈥? were used for hydrate formation, which corresponded to the clathrate structures of TBPO路34.5H₂O and 28H₂O, respectively. The phase boundary at both concentrations was shifted to the promotion region represented by lower pressures and higher temperatures, compared to each simple gas hydrate. In particular, TBPO + CO₂ double hydrate presented mild hydrate stabilization conditions of <1 MPa at (280 to 285) K. Additionally, the dissociation enthalpy (螖H_d) calculated from the phase boundary curves for the TBPO + CO₂ double hydrates was almost the same as that for tetra-n-butylammonium bromide (TBAB) + CO₂ double hydrate (219.5 kJ路mol^鈥? for m = 1.61 mol路kg^鈥? and 211.6 kJ路mol^鈥? for m = 1.98 mol路kg^鈥?). These results demonstrate that the TBPO + CO₂ double hydrate could be used as refrigerants for cold storage and transportation.