Fluorine-free and hydrophobic room-temperature ionic liquids,tetraalkylammonium bis(2-ethylhexyl)sulfosuccinates,and their ionic liquid-water two-phase properties

摘要

Fluorine-free and hydrophobic room-temperature ionic liquids (RTILs) composed of the bis(2-ethylhexyl)sulfosuccinate (BEHSS) ion,which is known as the surface-active anion constituting Aerosol OT~R,and symmetric tetraalkylammonium ions ((C_nH_(2n+1))_4N~+;n=4-8),have been prepared.Physicochemical properties of the water-saturated RTILs such as density,conductivity,viscosity and mutual solubility with water (W) have been measured.The RTIL|W interface is polarizable for the RTILs with n-5-8 in spite of the high water content,3.6-8.9 wt% in the water-saturated RTILs.The width of the polarized potential window of the RTIL|W interfaces is quantitatively correlated with the solubility of the RTIL in W.The RTIL-W two-phase systems are not spontaneously emulsified and no reverse micelles are formed in the water-saturated RTILs,although BEHSS~- is known to form stable water-in-oil emulsions and reverse micelles in oil-water two-phase systems.