Determination of excess Gibbs functions of binary liquid mixtures from measurements of dew pressure and composition of vapour. Test of the method on benzene + cyclohexane

Abstract

Measurements of dew pressures pd and mole fractions y of gaseous mixtures of benzene + cyclo hexane at 313.15 K are shown to lead to excess Gibbs functions GE in close agreement with thos calculated from Scatchard, Wood, and Mochel's measurements, made with a recirculating still, o vapour pressure p, mole fraction x in the liquid phase, and mole fraction y in the gaseous phase. The results of both sets of (p,y) measurements are analysed by solving the Gibbs–Duhem equation for x, as well as by the more usual but more difficult method of obtaining x by assuming an explicit form for GE(x). The two methods of analysis give GE values which agree closely with one another, and which also agree well with those calculated from Scatchard, Wood and Mochel's measurements of x.