The phase equilibrium of MnSO₄ in water-alcohol solution is indispensable for the separation and purification of MnSO₄ based on solvent-out effects. To investigate the phase behavior of MnSO₄ in water-alcohol solution, the phase equilibrium of CH₃CH₂OH + MnSO₄ + H₂O systems at 303.15 and 313.15 K and the (CH₃)₂CHOH + MnSO₄ + H₂O system at 303.15 K has been determined. Five regions, namely, L (liquid), L₁ + S (liquid 1 + solid), L₁ + L₂ (liquid 1 + liquid 2), L₁ + L₂ + S (liquid 1 + liquid 2 + solid), and L₂ + S (liquid 2 + solid), are observed. Furthermore, the effects of alcohol types and temperatures on the formation of aqueous two-phase systems (ATPSs) are discussed in detail. It is found that the three experimental systems are partially miscible systems. The (CH₃)₂CHOH + MnSO₄ + H₂O system has a larger split phase region and better solvent-out effect than the CH₃CH₂OH + MnSO₄ + H₂O systems. Meanwhile, the temperature has a slight influence on the phase behavior and the formation of ATPSs. The solubility of MnSO₄ decreases with an increasing alcohol concentration. In addition, the relationship between the w(MnSO₄) and w(alcohols) of the binodal curves is obtained based on the Mistry equation, Merchuk equation, and Pirdashti equation. The NRTL model is applied to fit the liquid–liquid equilibrium. The correlation coefficients show that the experimental data is in good agreement with the calculated values. It is worth mentioning that the equilibrium solid phase is MnSO₄·H₂O. This work provides basic data for manganese sulfate purification and can be applied to develop thermodynamic models of ATPSs.

中文翻译：

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乙醇/异丙醇+硫酸锰+水三元体系相平衡的测定及相关性

_{MnSO 4}在水-醇溶液中的相平衡对于基于溶出效应的MnSO ₄的分离和纯化是必不可少的。为了研究 MnSO ₄在水-醇溶液中的相行为，CH ₃ CH ₂ OH + MnSO ₄ + H ₂ O 体系在 303.15 和 313.15 K 和 (CH ₃ ) ₂ CHOH + MnSO ₄ + H ₂的相平衡已确定 303.15 K 的 O 系统。五个区域，即L（液体）、L ₁ + S（液体1+固体）、L ₁ + L ₂（液体1+液体2）、L ₁观察到+L ₂ + S（液体1+液体2+固体）和L ₂ + S（液体2+固体）。此外，还详细讨论了醇类型和温度对水性两相系统 (ATPS) 形成的影响。发现三个实验体系是部分混溶体系。(CH ₃ ) ₂ CHOH + MnSO ₄ + H 2 O体系比CH 3 CH 2 OH + MnSO 4 + H _{2 O}体系_具有更大_的分_相区和更好的溶剂去除效果。同时，温度对相行为和ATPSs的形成有轻微影响。MnSO _{4的溶解度}随着酒精浓度的增加而减少。另外，基于Mistry方程、Merchuk方程和Pirdashti方程，得到双节曲线的w (MnSO ₄ )和w (醇)之间的关系。NRTL 模型用于拟合液-液平衡。相关系数表明，实验数据与计算值吻合较好。值得一提的是，平衡固相为MnSO ₄ ·H ₂ O。这项工作为硫酸锰提纯提供了基础数据，可用于开发ATPSs的热力学模型。