Phase Equilibria and Salt Effect on the Aqueous Two-Phase System of Polyoxyethylene Cetyl Ether and Sulfate Salt at Three Temperatures
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- 作者：Yang Lu ; Miao Yu ; Zhenjiang Tan ; Yongsheng Yan
- 刊名：Journal of Chemical & Engineering Data
- 出版年：2016
- 出版时间：June 9, 2016
- 年：2016
- 卷：61
- 期：6
- 页码：2135-2143
- 全文大小：410K
- 年卷期：0
- ISSN：1520-5134
文摘
Polyoxyethylene(20) cetyl ether (C56H114O21, POELE20) and three sulfate salts (Li2SO4, ZnSO4, and MgSO4) were used as phase-forming material of the aqueous two-phase system, and the binodal data was measured at the three temperatures (288.15, 298.15, 308.15 K). Three classic experienced formulas were used to fit the binodal data, and they had better performance in data association. The tie-line data of studied systems were measured and fitted by the empirical formulas, i.e., Othmer–Tobias and Bancroft equations. It has better performance in data association. For the investigated systems, the influence of the salt type on the binodal curves was studied by the Gibbs free energy of ions hydration and effective excluded volume, and the influence of temperature on the tie-lines and binonal curves was also discussed. First, as it is confirmed, when the salts are of the same anion, salts with higher cation valence will have stronger abilities of salting out; the salting out abilities of salts strengthen with the increasing absolute value of Gibbs free energies of cations. Second, the salting-out abilities of salts enhance with the increase in system effective excluded volume in the investigated systems. Third, the studied aqueous two-phase systems are more prone to formation at the higher temperature than those at lower temperature. Finally, for the tie-lines in the studied systems, the absolute value of slope decreases with the temperature falling.