中文摘要：

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。

英文摘要：

There is a narrow aqueous two-phase system（ ATPS） region near the side of water-ionic liquid found by drawing the ternary phase diagram of the system of 1-butyl-3-methylimidazolium tetrafluoroborate（ [Bmim]BF4）,sodium dodecylbenzenesulfonate（ SDBS） and water using ocular estimate and turbidity method at 298. 15 K. The enthalpy change of series samples with different compositions around this region after injecting triply distilled water are investigated by isothermal titration microcalorimetry（ ITC）. It is found that there are weak endothermic and exothermic processes appearing separately with increasing the water content,which matches perfectly with the location of the formation and disappearance of the aqueous two-phase in the ternary phase diagram. This suggests the ITC is a feasible and effective method for the thermodynamic study of aqueous two-phase systems. The experimental results showed that the formation of the aqueous two-phase system is endothermic（ ΔH 0）,but the process of disappearing is exothermic（ ΔH 0）. Due to the formation of aqueous two-phase is a thermodynamic spontaneous process under the isothermal constant pressure,it can be considered that the formation of this aqueous two-phase system is an entropy driven course and the vanishing is a synergy driven process by entropy and enthalpy.