The thermodynamics of the dimethyl sulphoxide - methanol system

Abstract

An extensive literature survey of previous research on the DMSO-methanol system and of the thermodynamic properties of the pure components, was carried out. The densities of binary mixtures over the entire composition range 0.000 mole fraction DMSO to 1.000 mole fraction DMSO were determined pycnometŕically at 25°, 30°, 35°, 40°, 45° and 50°C in order to obtain the coefficients of thermal expansion. Internal pressures (∂U/∂V)T, have been derived from experimentally measured thermal pressure coefficients, (∂P/∂T)V for DMSO-methanol mixtures. These data, together with the temperature dependence of the thermal pressure coefficient, are used to interpret structural changes in the solvent system as a function of composition. Thermodynamic parameters of mixing at constant volume for this system are also calculated and discussed.