Thermodynamics of Ketone + Amine Mixtures Part V. Volumetric and Speed of Sound Data at (293.15, 298.15 and 303.15) K for Mixtures of 2-Heptanone with Aniline, N-Methylaniline or Pyridine

Densities, ρ, and speeds of sound, u, of 2-heptanone + aniline + N-methylaniline or + pyridine systems have been measured at (293.15, 298.15 and 303.15) K and atmospheric pressure using a vibrating tube densimeter and sound analyzer. The ρ and u values were used to calculate excess molar volumes, V ^E, and the excess functions at 298.15 K for the speed of sound, u ^E, the thermal expansion coefficient, a_p^Ealpha_{p}^{mathrm{E}}, and for the isentropic compressibility, k_S^Ekappa_{mathrm{S}}^{mathrm{E}}. V ^E and k_S^Ekappa_{mathrm{S}}^{mathrm{E}} are both negative and increase in the sequence: aniline <N-methylaniline < pyridine. In contrast, u ^E is positive and changes in the opposite way. The data suggest the existence of interactions between unlike molecules, which are much weaker in the pyridine solution. Aromatic amine–alkanone interactions are stronger in mixtures with acetone. The linear dependence of Rao’s constant with concentration reveals that there is no complex formation in the investigated systems.