山形大学紀要（工学） 第11巻 第1号（1970）45-53
A New Method for the Deterinination of the Dissociation
Pressures of Salt Hydrates
Yoshio YOKOYAMA, Gihee KONNO
A new method for the determination of the dissociation pressures of salt hydrates was described. The principle of the method consists in equilibrating the pair of salt hydrates with some organic liquid at a given temperature, and measuring the total pressure at the point which the first bubble has appeared by evacuation or the last bubble has disappeared by introduction of inert gas. The dissociation pressures of salt hydrates were obtained from the following equation;
where, p_d, P, p_c are dissociation pressure of salt hydrate, total pressure and partial pressure of organic solvent in liquid respectively, and h_lp_lg/(g_c) is the static pressure over the sample salts
The dissociation pressures of CuSO_4.5H_2O, Na_2HPO_4.12H2_O and Na_2H PO_4.7H_2O were measured and these results were in fair agreement with the data of other investigators.
This method has an advantage that is easy to operate and to approach equilibrium in a short time.