Excess properties of methanol-water binary system at various temperatures

Summary  In this study the viscosities of binary mixtures of methanol and water have been measured in the temperatures ranging from 15 to 45°C. The structural changes occurring as a consequence of molecular interactions in the solutions have been discussed in detail. Nevertheless, it would be of interest to see whether the information obtained from viscosity studies can be corroborated with that obtained from dielectric-constant data. With this aim, the present study on the dielectric behaviour of methanol-water binary solutions has been undertaken. The static dielectric constants, densities and refractive indices have been also measured on the methanol-water mixtures expressed by the mole fraction of methanol (02<1). Excess dielectric constants, excess volumes, excess viscosities and excess Gibbs energies of activation of the viscous flow and Kirkwood correlation factors have been evaluated using experimental results since these calculations may lead to conclusions concerning the deviation of the system from an ideal-mixture behaviour.