Excess thermodynamic functions derived from densities and surface tensions of (p- or o-xylene + ethylene glycol dimethyl ether) between the temperatures (298.15 and 308.15) K

摘要

Densities (ρ) for binary systems of (p-xylene or o-xylene + ethylene glycol dimethyl ether) were measured over the full mole fraction range at the temperatures of (298.15, 303.15 and 308.15) K along with the densities of the pure components. The excess molar volumes (V~E) calculated from the density data show that the deviations from ideal behaviour in the two binary systems are negative, and they become more negative with the temperature increasing. Surface tensions (σ) of these binary systems were determined at the same temperatures (298.15, 303.15 and 308.15) K by the pendant drop method. The surface tension deviations (δσ) for p-xylene system are negative over the whole composition range, and become less negative with the temperature increasing, but for the o-xylene system, δσ are negative at high o-xylene concentration, and change to positive with the o-xylene concentration decreasing. The V~E and δσ were fitted to the Redlich-Kister polynomial equation. Surface tensions were also used to estimate surface entropy (S_σ) and surface enthalpy (H_σ).