Volumetric and viscosimetric properties of [bmim][DCA] + γ-butyrolactone binary mixtures

In this paper experimental densities and dynamic viscosities of pure 1-butyl-3-methylimidazolium dicyanamide ionic liquid, [bmim][DCA], and its binary liquid mixtures with γ-butyrolactone (GBL) are reported. All measurements were performed in the temperature range from (273.15 to 323.15) K at the pressure of 0.1 MPa for the various mixture compositions. From the experimental density the related volumetric parameters were calculated and fitted using Redlich-Kister's polynomial equation. Obtained values are compared to those previously obtained for GBL mixtures with imidazolium and pyrrolidinium based ionic liquids containing bis(trifluoromethylsulfonyl)imide and dicyanamide anions. Other volumetric properties, such as isobaric thermal expansion coefficients, partial molar volumes and partial molar volumes at infinite dilution were also calculated, in order to obtain information about the interactions between GBL and the studied ionic liquid. From the viscosity results, the Angell strength parameter was calculated and found to be 3.75 indicating that [bmim][DCA] is a “fragile” liquid.