Densities and excess volumes of binary mixtures of the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate with aromatic compound at T = (298.15 to 313.15) K

The density of two binary mixtures formed by 1-butyl-3-methylimidazolium hexafluorophosphate [bmim][PF6] with aromatic compound (benzyl alcohol or benzaldehyde) has been determined over the full range of compositions at the temperature range from 298.15 K to 313.15 K and at atmospheric pressure using a vibrating-tube densimeter (DMA4500). Excess molar volumes (VmE) have been obtained from these experimental results, and been fitted by the fourth-order Redlich–Kister equation. Our results show VmE decreases slightly when temperature increases in the systems studied. The results have been interpreted in terms of ion–dipole interactions and structural factors of the ionic liquid and these organic molecular liquids.