The densities and viscosities of a binary liquid mixture of 1-n-butyl-3-methylimidazolium tetrafluoroborate, ([Bmim][BF4]) with acetone, methyl ethyl ketone and N,N-dimethylformamide, at 303.15 to 333.15 K

• Density and viscosity data of three ionic liquid binary mixtures are measured.
• Studied binary mixtures include [Bmim][BF4] with acetone, methyl ethyl ketone and N,N-dimethylformamide.
• Excess molar volumes and viscosity deviations are calculated, correlated and compared.

In this study, thermodynamic properties of a binary mixture of ionic liquid and organic solvent as a potential solvent system in pharmaceutical industry are studied. The densities and viscosities of the binary liquid mixture of ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF4]), with acetone, methyl ethyl ketone (MEK) and N,N-dimethylformamide (DMF), are measured at different temperatures (303.15, 313.15, 323.15 and 333.15 K) and atmospheric pressure, over the entire range of compositions. The densities are measured using a vibrating-tube digital density meter and the viscosities are measured using a capillary viscometer. The changing trends of densities and viscosities with temperature and composition are discussed. In addition, the excess molar volumes and viscosity deviations for the binary liquid mixture are calculated and then fitted to the Redlich–Kister polynomials. The optimally fitted parameters are presented and the correlation results show satisfactory agreement with the experimental data. Furthermore, the excess molar volumes of the binary mixtures are also compared and discussed by the viewpoint of molecular interaction.