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

ABSTRACT

The effect of some imidazolium based ionic liquids including 1-propyl-3-methylimidazolium bromide ([PMIm]Br), 1-pentyl-3-methylimidazolium bromide ([PnMIm]Br), 1-hexyl-3-methylimidazolium bromide ([HMIm]Br), and 1-hexyl-3-methylimidazolium chloride ([HMIm]Cl) on the volumetric and viscometric properties of N,N'-bis(2-pyridylmethylidene)-1,2-diiminoethane Schiff base (BPIE) in acetonitrile (CH3CN) solutions was studied at T = (298.15 to 313.15) K. The measured densities were used to calculate apparent molar volumes (V?) which were utilized to obtain standard partial molar volumes (V?0) of the ionic liquids. The temperature dependence of the V?0 values was examined by determination of partial molar expansivity (E?0 = (?V?0/?T)P) and thermal expansion coefficient at infinite dilution (a = E?0/V?0)). Moreover, the pair (VSIL) and triplet (VSSIL) interaction coefficients were estimated based on McMillan and Mayer s theory. The calculated Helper s constants ((?2V?0/?T2)P) indicate that the ionic liquids being studied behave as a structure-breaker in the solutions. To confirm the volumetric results, viscosities of the solutions were measured using an Ubbelohde-type viscometer. The viscosity values were used to calculate viscosity B-coefficients by the Jones Dole equation and the solvation numbers (B/V?0) of the ionic liquids in the solutions. The effect of anion and cation size of ionic liquids on the calculated parameters was also examined. The results were used to deduce various interactions in the ternary solutions. It is concluded that the Schiff base IL interactions are strengthened as the Schiff base concentration increases in the solution.