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在298.15 K下使用目测法和浊度法绘制了四氟硼酸1-丁基-3-甲基咪唑鎓([Bmim]BF4)/十二烷基苯磺酸钠(SDBS)/水组成的三元体系相图,得到了一个靠近离子液体和水一侧的狭窄双水相(ATPS)区域。从双水相区域周围选择不同组成的样品,用等温滴定微量热(ITC)方法测定了这些样品中逐滴加入纯水后体系热量的变化,发现随样品中水含量的增加,量热曲线上分别出现了较弱的吸热和放热过程,而且这两个过程的位置与三元相图中双水相的形成和消失的位置基本吻合,这说明ITC对于双水相体系的热力学研究是一种可行有效的方法。实验结果表明,双水相的形成是一个吸热过程(ΔH>0),而消失是放热过程(ΔH<0)。由于双水相的形成是等温等压下的热力学自发过程(ΔG<0),因此可以判断该体系中双水相的形成是一个熵驱动过程,而消失是一个熵-焓共驱过程。
Visualization and turbidimetry were used at 298.15 K to plot the composition of 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim] BF4) / sodium dodecylbenzenesulfonate (SDBS) / water Element phase diagram, a narrow twin aqueous phase (ATPS) region near the ionic liquid and water side was obtained. The samples with different compositions were selected around the aqueous two-phase region. The isothermal titration calorimetry (ITC) method was used to determine the change of caloric value of the sample after pure water was added dropwise. The results showed that with the increase of water content in the sample, Respectively, and the weaker endotherms and exothermic processes appeared. The positions of the two processes are basically consistent with the formation and disappearance of the two water phases in the ternary phase diagram. This shows that ITC’s thermodynamic study on the two-phase system is A viable and effective method. The experimental results show that the formation of the double aqueous phase is an endothermic process (ΔH> 0), while the disappearance is the exothermic process (ΔH <0). Since the formation of a double aqueous phase is a thermodynamic spontaneous process (ΔG <0) at isothermal isobaric pressure, it can be concluded that the formation of a hydrous phase in the system is an entropy-driven process, whereas disappearance is an entropy-enthalpy co-flooding process.