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

ABSTRACT

Density measurements were carried out for aqueous solutions of the ionic liquids [BMIm]Cl, [BMIm]Br, [BMIm][BF4], [HMIm]Br, [OMIm]Br, [MMIm][MSO4], and [EMIm][ESO4] at T = (288.15 318.15) K. The measured densities were used to compute the standard partial molar volumes (V?0) of the ILs using Redlich Mayer and Pitzer equations. The results show that the V?0 values obtained from both equations are fully compatible and that the difference is less than 0.5 cm3*mol 1 for all the ionic liquids. The first derivative of V?0 with respect to temperature give the values of partial molar expansivity (E?0), and its second derivative with respect to temperature provided Hepler s constant ((?2V?0/?T2)P) an important parameter to discuss the structure-making or -breaking tendency of the ILs in aqueous solutions. The values of (?2V?0/?T2)P for all the ILs except for [OMIm]Br were found to be negative, showing that these ILs behave as structure breakers in aqueous media.