Thermodynamics Research Center / ThermoML | International Journal of Thermophysics

ABSTRACT

Speeds of sound, u ijk , of tetrahydropyran (THP) (i) + benzene (j) + toluene or o- or p-xylene (k), and tetrahydropyran (i)+toluene (j) + o- or p-xylene (k) ternary mixtures have been measured over the entire mole fraction range at 308.15 K and atmospheric pressure. The speed-of-sound data have been used to calculate isentropic compressibilities, (S)ijk , and excess isentropic compressibilities, (SE)ijk . The (SE)ijk values for the investigated mixtures are correlated with the Redlich Kister equation to estimate ternary adjustable parameters and standard deviations. The Moelwyn Huggins concept (Huggins, Polymer 12:357, 1971) of interaction between the surfaces of components of binary mixtures has been extended to predict excess isentropic compressibilities of ternary mixtures by employing the concept of connectivity parameters of the third degree of a molecule (which in turn depends on its topology). It has been observed that (S)ijk values predicted by the Moelwyn Huggins concept compare well with corresponding experimental values.