Thermodynamic properties of PEG-based functionalized imidazolium toluenesulfonate ionic liquids

A series of PEG-based functionalized imidazolium toluenesulfonate ionic liquids (PBILs), which exhibit extremely high SO2 solubility, were prepared. The density and surface tension of PBILs ([M-PEG350Mim][Tosyl], [M-PEG500Mim][Tosyl] and [M-PEG700Mim][Tosyl]) have been measured in the temperature range from 293.15 K to 333.15 K. The coefficients of thermal expansion were calculated from the experimental density results using an empirical correlation. Molecular volume and standard entropies of these ILs were calculated from the experimental density values. The surface properties of ILs were investigated. The critical temperatures and enthalpies of vaporization were also discussed.