温度对季鏻盐离子液体微乳液相行为的影响

Effect of Temperature on Phase Equilibrium for Microemulsions Containing Phosphonium-based Ionic Liquids

【目的】分析温度对季鏻盐离液体微乳液相行为的影响规律。【方法】以季鏻盐离子液体为非极性相,水为极性相,TX-100/正丁醇为表面活性剂,构建5种微乳液体系,绘制拟三元相图、测定流变特性。【结果】高温有利于四丁基三氟乙酸膦([P_(4444)]CF_3COO)、三丁基辛基溴化膦([P_(4448)]Br)形成微乳液,低温利于四丁基四氟硼酸膦([P_(4444)]BF_4)、三丁基辛基三氟乙酸膦([P_(4448)]CF_3COO)、三丁基辛基四氟硼酸膦([P_(4448)]BF_4)形成微乳液。其中[P_(4444)]CF_3COO和[P_(4448)]Br具有低临界溶解温度(LCST)的相转变行为,[P_(4444)]BF_4、[P_(4448)]CF_3COO和[P_(4448)]BF_4具有高临界溶解温度(UCST)的相转变行为。5种季鏻盐离子液体微乳液的黏度均随温度升高而显著下降,流体类型由假塑性流体趋向于牛顿流体。【结论】温度是影响季鏻盐离子液体微乳液相平衡的重要因素。

【Objective】 The effect regulation of temperature on the phase behavior of microemulsions containing phosphonium-based ionic liquids（ILs） was studied. 【Method】Five microemulsions were successful formed with phosphonium-based IL as non-polar phase, water as polar phase, and TX-100/n-butanol as surfactant. The phase diagrams and rheological properties of the microemulsions were investigated.【Result】 Results show that tetrabutylphosphonium trifluoroacetate（[P（4444）]CF3COO）-and tributyloctylphosphonium bromide（[P（4448）]Br）-based microemulsions could be formed at a higher temperature, which was classified as a lower critical solution temperature（LCST）-type phase transition. The microemulsions containing tetrabutylphosphonium tetrafluoroborate（[P（4444）]BF4）, tributyloctylpho-sphonium trifluoroacetate（[P（4448）]CF3COO） or tributyloctylphosphonium tetrafluoroborate（[P（4448）]BF4） preferred to be formed at a lower temperature, which underwent an upper critical solution temperature（UCST）-type phase behavior. The viscosity of the five microemulsions decreased significantly and fluid types of pseudoplastic tended to Newtonian fluids with the increase of temperature.【Conclusion】Temperature is an important factor for the phase equilibrium of microemulsions containing phosphonium-based ILs.