Density and Viscosity of Ionic Liquid Binary Mixtures of 1-n-Butyl-3-methylimidazolium Tetrafluoroborate with Acetonitrile, N,N-Dimethylacetamide, Methanol, and N-Methyl-2-pyrrolidone

In this study, thermodynamic properties of the binary mixtures of ionic liquid with an organic compound, as potential solvent systems in pharmaceutical industry applications, are studied. The densities and viscosities of the binary mixtures of 1-butyl-3-methylimidazolium tetrafluoroborate ([C(4)mim][BF4]) with acetonitrile, N,N-dimethylacetamide, methanol, and N-methyl-2-pyrrolidone were measured at atmospheric pressure over the [C(4)mim][BF4] mole fraction range from 0.1 to 0.9 and at temperatures from 303.15 to 333.15 K at intervals of 10 K. The densities were measured using a vibrating-tube digital density meter and the viscosities were measured using a capillary viscometer. The excess molar volumes (V (E)) and viscosity deviations (Delta eta) were calculated from densities and viscosities of mixture, respectively, and fitted to the Redlich-Kister polynomial. The optimally fitted parameters are also determined and the correlation results are in satisfactory agreement with the experimental data. In addition, the excess molar volumes of binary mixtures of ionic liquid with different organic compounds are compared and discussed using the Hansen solubility parameter.