Tracer Diffusion and Shear Viscosity for the System 2,6-Lutidine-Water near the Lower Critical Point

Abstract

Tracer diffusion coefficients of tritiated water in mixtures of 2,6‐lutidine‐water have been measured over the entire concentration range at ${\text{ε =1.1× 10}}^{\text{−4}}$ below the critical point using the diaphragm cell. No anomaly was detected. The shear viscosity coefficients were measured across the entire concentration range at ${\text{ε =2.246× 10}}^{\text{−2}}{\text{, 1.268× 10}}^{\text{−2}}{\text{, 7.8× 10}}^{\text{−5}}$ by a closed capillary viscometer. The observed anomaly in the region of the critical point was further characterized by studying the temperature dependence of the viscosity of a mixture at critical composition. These data are discussed in terms of Kawasaki's mode‐mode coupling theory.