Volumetric Properties of Binary Mixtures of the Ionic Liquid 1-Butyl-3-Methylimidazolium Tetrafluoroborate with Aniline

The densities of binary mixtures of an ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate, [bmim][BF4], with an aromatic compound, aniline, have been determined over the full range of compositions and over the temperature range 298.15 to 313.15 K at atmospheric pressure using a vibrating-tube densimeter (DMA4500). Excess molar volumes (V-m(E)) have been obtained from these experimental results, and were fitted by the fourth-order Redlich-Kister equation. In addition, partial molar volumes, apparent molar volumes and partial molar volumes at infinite dilution have been calculated for each component. Our results show that values of V-m(E) decrease slightly when the temperature increases in this system. The results have been interpreted in terms of ion-dipole interactions and structural factors of the ionic liquid and the organic molecular liquid.