Densities and Volumetric Properties of Binary Mixtures of Tetrahydrofuran with Some Aromatic Hydrocarbons at Temperatures from 278.15 to 318.15 K

The densities, ρ, of binary mixtures of tetrahydrofuran (THF) with benzene, toluene, o-xylene, m-xylene, p-xylene and mesitylene, including those of the pure liquids, were measured over the entire composition range at the temperatures (278.15, 283.15, 288.15, 293.15, 298.15, 303.15, 308.15, 313.15 and 318.15) K and atmospheric pressure. From the experimental data, the excess molar volume, V _m ^E, partial molar volumes, _m,1 ^∘ and _m,2 ^∘, and excess partial molar volumes, _m,1 ^∘E and _m,2 ^∘E, at infinite dilution were calculated. The V _m ^E values were found to be negative over the whole composition range for all of the mixtures and at each temperature studied, except for THF + mesitylene, which exhibits a sigmoid trend wherein V _m ^E changes sign from negative to positive as the concentration of THF in the mixture is increased, indicating the presence of specific interactions between THF and aromatic hydrocarbon molecules. The extent of negative deviations in the V _m ^E values follows the order: benzene > toluene > p-xylene > m-xylene > o-xylene > mesitylene. It is observed that the V _m ^E values depend upon the number and position of the methyl groups in these aromatic hydrocarbons.