Interdiffusion Coefficient and Dynamic Viscosity for the Mixture 2,6-Lutidine + Water near the Lower Consolute Point

Abstract

Abstract The mixture, 2,6-lutidine + water has a lower consolute point at a temperature of 33.9°C and a lutidine concentration of 2.78 M. The interdiffusion coefficient of this mixture was measured over a wide range of concentrations along the isotherms at 25.00°C and 33.00°C, and over a wide range of temperatures along the critical isopleth. Critical slowing down of diffusion was evident along all three paths. The dynamic viscosity was measured along the isotherm at 25.00°C and along the critical isopleth at temperatures below critical. Along the critical isopleth, the viscosity increased rapidly as the critical temperature was approached. These data are discussed in terms of the cross over function theory, which is used to connect divergent data near the critical point to smoothly varying data away from the critical point.