Thermodynamics of solutions of polypropylene oxide in chloroform and in carbon tetrachloride

Abstract

Measurements are reported of the vapour pressures, the heats and volumes of mixing, and the thermal pressure coefficients of solutions of polypropylene glycol dimethyl ether in chloroform and in carbon tetrachloride. For the calorimetry, a new and extremely simple type of mixing vessel for an isothermal calorimeter was designed which enabled two liquid components to be mixed at constant pressure without the presence of any vapour space above the liquids. The measurements have been used to calculate the thermodynamic mixing functions for mixing with zero volume change, which are compared with the predictions of the generalized lattice theory. The thermodynamic behaviour of the hydrogen-bonding chloroform solutions is predicted more closely by the use of the “zeroth approximation” in the lattice theory than by the use of the “first” or “quasi-chemical” approximation. The behaviour of the carbon tetrachloride solutions is predicted within experimental error by the simple Flory equations.