Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

ABSTRACT

Non-ideal behaviour of the room temperature ionic liquids (RTILs), 1-butyl-3-methylimidazolium tetrafluoroborate [bmim][BF4]; 1-octyl-3-methylimidazolium tetrafluoroborate [omim][BF4] and 1-butyl-3-methylimidazolium octylsulfate [bmim][C8OSO3] in ethylene glycol [HOCH2CH2OH] (EG) have been investigated over the whole composition range at T = (298.15 to 318.15) K. For the purpose, volumetric properties such as excess molar volumes, View the MathML source, apparent molar volumes, Vphi,i, partial molar volumes, View the MathML source, excess partial molar volumes, View the MathML source, and their limiting values at infinite dilution, View the MathML source, View the MathML source, and View the MathML source respectively have been calculated from the experimental density measurements. The View the MathML source results have been analyzed using the Prigogine Flory Patterson (PFP) theory. PFP theory has satisfactorily explained the volumetric behaviour of the binary mixtures. Refractive index measurements at 298.15 K have been used to calculate the deviations in refractive indices ?phin and the deviation of molar refraction ?xR from their respective ideal values. Refractive index results have been correlated with volumetric results, and have been interpreted in terms of molecular interactions. Excess properties are fitted to the Redlich Kister polynomial equation to obtain the binary coefficients and the standard errors.