Thermodynamics Research Center / ThermoML | Journal of Chemical and Engineering Data

ABSTRACT

The ternary critical mixture of 1,4-dioxane (1) + water (2) + saturated KCl (3) has a lower critical point. The viscosity ? and electrical conductivity ? of this system have been measured as function of temperature for nine critical mixtures along the coexistence curve below the temperature of phase transition. The water mole fraction in free basis x?2 in the mixtures extends from (0.550 to 0.880) and the molality m of KCl from (0.47 to 2.039) mol*kg-1. The viscosity was found to decrease with an increase in temperature, water mole fraction, and the molality of KCl, while the electrical conductivity increases with an increase in temperature, with the water mole fraction and molality of salt. The viscosity and electrical conductivity represented anomalies near the critical temperature Tc. The critical electrical conductivity ?c varies with water mass fraction w2 as a second degree polynomial and with the molality m of salt as a third degree polynomial. The variation of critical composition in water and in the molality of salt varied the temperature of separation of phase, Tt. The activation energy Ea(?) for ionic conduction decreased with increasing x?2 and consequently with molality, but they are not influenced in the activation energy Ea(?) for viscous flow.