Thermodynamics Research Center / ThermoML | Journal of Chemical and Engineering Data

ABSTRACT

In this work, we measured the densities of twenty protic ionic liquids (PILs) based on four different cations: diethylammonium, triethylammonium, dimethylethylammonium and triethanolammonium, and fourteen anions of the following acids: phosphoric, acetic, trifluoroacetic, methanesulfonic, trifluoromethanesulfonic, benzoic, salicylic, propanoic, sulfuric, nitrobenzenesulfonic, sulfobenzoic, salicylic, sulfosalicylic, and bis(trifluoromethylsulfonyl)imide ones. The values of density were measured over the temperature range from 293.15 to 353.15 K by densimeter based on the vibrating tube principle and they were approximated by a polynomial as a function of temperature. The thermal expansion coefficients were calculated; the fractional free volume in the molar volume of the studied PILs was estimated, and the influence of the ion structure on their volumetric properties was analysed. Two different group contribution methods were analysed to determine their applicability to predicting the density of the studied PILs.