Abstract: A method for the measurement of excess thermodynamic functions of ternary—— pseudobinary liquid mixtures
(1-x)[(1-y)A+yC]+x[(1-y)B+yC]
has been proposed. The excess volumes of two systems A=cyclohexane, B=benzene, C=toluene or methylcyclohexane have been measured at 298.15 K. Using vdW one-fluid approximation and the classical van der Waals equation, the vdW parameters of pure fluids have been evaluated by the least squares method from the V~E data of binary system. Moreover, the excess volumes of pseudobinary system can be calculated with appropriate vdW parameters of pure fluids. It has been found that the calculated values are in fairly good agreement with the experimental results.

Key words: Ternary——psendobinary, Excess volumes