Excess molar volumes and excess logarithm viscosities for binary mixtures of the ionic liquid 1-butyl-3-methylimidazolium hexaflurophosphate with some organic compounds

Experimental data of densities and viscosities are presented for the mixtures of the ionic liquid 1-butyl-3-methylimidazolium hexaflurophosphate, [C(4)mim][PF6], with acetone, 2-butanone, 3-pentanone, cyclopentanone and ethyl acetate at 298.15 K. Based on these data, excess molar volumes, V-m(E), and excess logarithm viscosities, (ln eta)(E), have been determined for the binaries. It is shown that all values of V-m(E) are negative but those of (ln eta)(E) are positive. Interestingly, a minimum in V-m(E) and a maximum in ( ln eta)(E) are observed at about the same mole fraction of the ionic liquid ( x = 0.3) for every mixture investigated. Combined with the V-m(E) data reported in literature, the effects of the [PF6](-) and [BF4](-) anions are compared. The results have been discussed in terms of the ion dipole interactions of the cations of the ionic liquids with the organic compounds as well as their influence on the association of [C(4)mim](+) and [PF6](-) in the ionic liquid.