三元体系PEG4000-Cs_2SO_4H_2O在25,35和45℃时的相平衡研究

Phase Equilibrium of Ternary System PEG 4000(Poly ethylene glycol)-Cs_2SO_4-H_2O at 25, 35 and 45 ℃

采用自制的相平衡研究装置 ,测定了PEG 40 0 0 Cs2 SO4 H2 O三元体系在 2 5 ,3 5和 45℃时的等温平衡溶解度 ,同时给出了该体系的完整相图 ,在相图中观察到 6个相区。结果表明 ,该体系双液相区随着温度的升高略有增加 ,结线的斜率也随温度的升高而增大。用四参数方程y=a +bx0 .5+cx +dx2 对该体系的双液线进行了拟合 ,拟合结果较好。用Othmer Tobias方程和Bancroft方程对该体系结线的实验数据进行了关联 ,所有线性相关系数均大于 0 .98。热重分析确定平衡固相组成为无水硫酸铯。

Liquid-liquid equilibrium and solid-liquid equilibrium data of the PEG 4000-Cs 2SO 4-H 2O ternary system were measured at 25, 35 and 45 ℃. The complete phase diagram of the system was given and six zones were found. The results show that two-phase area is expanded with the increasing temperature and the slope of the equilibrium tie line also increases. The binodal curves are obtained using the four-parameter equation, y=a+bx 0.5+cx+dx2, and tie lines are satisfactorily described using the Othmer-Tobias and Bancroft equations. Correlation coefficients (R) for all equations exceed 0.98. Samples of the solid phase analyzed by TGA show that it consists of anhydrous Cs 2SO 4.