The mutual diffusion coefficient for binary mixtures of water and the isomers of propanol

Abstract

Abstract Measurements of the mutual diffusion coefficient of the n-propanol-water and isopropanol-water systems have been performed at a pressure of 105 Pa by means of a flow technique. The results extend over the complete composition range for the mixtures and over the temperature range 25-65 °C. The reported diffusivities have an estimated uncertainty of + 2.5% Both the systems studied exhibit the minimum in the diffusivity as a function of composition at constant temperature which is characteristic of alcoho-lwater mixtures. In addition, a local maximum in the diffusivity occurs along an isotherm for alcohol-rich mixtures; this type of behaviour has not been observed hitherto. The data are compared with other transport and equilibrium properties for the mixtures, and with a simplified form of the statistical mechanical theory.