Tween80/BmimPF6/醇/甲苯体系的相行为

Phase Behavior of Tween80/BmimPF_6/Alcohol/ Toluene Systems

以环境友好型的Tween80为表面活性剂,以醇(乙醇、正丁醇、正己醇、正辛醇、正癸醇和异戊醇)为助表面活性剂,对离子液体1-丁基-3-甲基咪唑六氟磷酸盐(bmimPF6)和甲苯进行了微乳化实验,绘制了不同条件下Tween80离子液体的微乳体系的拟三元相图,考察了醇的种类、含量对单相微乳区的影响,并用电导法研究了在乙醇为助表面活性剂情况下,单相微乳区的结构转变.结果表明,当醇(异戊醇)固定时,随着表面活性剂/醇的质量比增加,单相微乳区的面积逐渐增大;不同链长的直链醇对单相微乳区的面积影响与该醇在离子液体中的溶解情况有关,单相微乳区的面积随着直链醇链长的增加而越小;当乙醇作助表面活性剂时,所得到的单相微乳区的面积最大,且单相微乳区存在着O/IL(oil-in-ionic liquid)、双连续相和IL/O(ionic liquid-in-oil)三种微结构.尤其对离子液体微乳体系的电导随油的含量的增加而最初增大的现象进行了解释,这一现象是由于油主要起到减少离子液体中离子对或离子的积聚,提高带电离子淌度的作用.

To investigate the influence of different alcohols on the isotropic microemulsion zone of a 1-butyl-3-methylimidazolium hexafluorophosphate （bmimPF6）/Tween80/toluene system, pseudo ternary phase diagrams of bmimPF6/Tween80/alcohol/toluene systems under different conditions were constructed. Alcohols used were C2H5OH, n-C4H9OH, n-C6H13OH, n-C8H17OH, n-C10H21OH, and i-C5H11OH. Effects of alcohol type and content on the formation of the microemulsion region were investigated. Phase diagrams showed that the microemulsion domain became larger as the Tween80/alcohol weight ratio increased for i-C5H11OH. Different chain lengths of alcohols affected the magnitude of microemulsion regions and this was also dependent on the alcohol solubility in bmimPF6. The single-phase microemulsion area decreased as the alcohol chain length increased. The single-phase region of the ethanol-containing system was the largest among the systems studied. Oil-in-ionic liquid （O/IL） microemulsions, bicontinuous microemulsions, and ionic liquid-in-oil （IL/O） microemulsions in isotropic regions were identified by conductivity measurements. Initial increases of conductivity in ionic liquid microemulsions with increased oil content was due to the oil decreasing ion pairs or ions accumulating in the ionic liquid microemulsion thus increasing the number of charge carriers and improving ionic mobility.