Thermodynamics of ethanol at low concentrations in mixtures of cyclohexane and 1,4-dimethylbenzene

Abstract

For the two-component system cyclohexane+1,4-dimethylbenzene we report (a) vapour-pressure measurements at 318.15 K and (b) enthalpy-of-mixing measurements at 288.15, 298.15 and 318.15 K. From these data we obtain activity coefficients at 318.15 and 298.15 K. Several compositions of this system are then used as mixed solvents, in which the enthalpy of dilution of ethanol is measured from ca. 0.1 mole fraction of ethanol down to below 0.001 mole fraction. The limiting partial excess enthalpy of ethanol is thus obtained as a function of the mole fractions of cyclohexane and 1,4-dimethylbenzene in the mixed solvent. This function is far from linear, and the actual values are compared with those calculable from the single-solvent data previously published.