Apparent Molar Volume and Isentropic Compressibility for the Binary Systems {Methyltrioctylammonium Bis(trifluoromethylsulfonyl)imide + Methyl Acetate or Methanol} and (Methanol + Methyl Acetate) at T=298.15, 303.15, 308.15 and 313.15 K and Atmospheric Pressure

Abstract

The densities and speeds of sound for binary mixtures containing the solute ionic liquid (IL) methyltrioctylammonium bis(trifluoromethylsulfonyl)imide ([MOA]+[Tf2N]−), solute/solvent methanol, and solvent methyl acetate have been measured at 298.15, 303.15, 308.15 and 313.15 K at atmospheric pressure. The binary mixtures studied are ([MOA]+[Tf2N]− + methyl acetate or methanol), and (methanol + methyl acetate). The apparent molar volume, Vφ and the apparent molar isentropic compressibility, kφ, have been evaluated from the experimental density and speed of sound data, respectively. The parameters of a Redlich–Mayer type equation were fitted to the apparent molar volume and apparent molar isentropic compressibility data. The apparent molar volume and apparent molar isentropic compressibility at infinite dilution, \(V_{\phi}^{0}\) and \(k_{\phi}^{0}\), respectively, of the binary solutions have also been calculated at each temperature. The infinite dilution apparent molar volume indicates that intermolecular interactions for (IL + methyl acetate) mixtures are stronger than for (IL + methanol) mixtures at all temperatures except at 298.15 K, and that \(V_{\phi}^{0}\) for the (IL + methyl acetate or methanol) binary systems increases with an increase in temperature. For the (methanol + methyl acetate) system the intermolecular interaction are weaker and \(V_{\phi}^{0}\) also increases with an increase in temperature. Values of the infinite dilution apparent molar expansibility, \(E_{\phi}^{0}\), indicate that the interaction between (IL + methyl acetate) is greater than for (IL + methanol) and (methanol + methyl acetate).