Thermodynamic and acoustic properties of binary mixtures of ethers. III. Diisopropyl ether or oxolane with o- or m-toluidines at 303.15, 313.15 and 323.15 K

Densities ρ and speeds of sound u, of binary mixtures formed by o-toluidine or m-toluidine with diisopropyl ether (DIPE) or oxolane have been measured over the entire range of composition at a temperature of (303.15, 313.15 and 323.15) K and atmospheric pressure. The ρ and u values were used to calculate isentropic compressibilities κS, Rao's molar sound functions R, intermolecular free lengths Lf, specific acoustic impedances Z  , excess molar volumes VmE, excess isentropic compressibilities κSE, excess intermolecular free lengths LfE and excess specific acoustic impedances ZE. The results have been used to investigate molecular interactions and structural effects in these mixtures. The speed of sound in present mixtures has been estimated using several empirical and theoretical models to determine their relative predicting ability in terms of pure component properties.

Research highlights
► We report excess properties of molar volumes, isentropic compressibilities, free lengths.
► Four binary mixtures of diisopropylether or oxolane with o- and m- toluidines are studied.
► Molecular interactions estimated qualitatively from magnitude of deviations in the properties.
► The free volume and P* effects has significant contributions in excess properties.
► The speeds of sound in mixtures were estimated with seven models.