Thermochimica Acta, Vol.352-353, 255-264, 2000
Heat capacities and thermal conductivity of ternary mixtures of water+ethanol+1,2-ethanediol between 75 and 350 K
The heat capacities of two concentrations of the ternary systems of 1,2-ethanediol, ethanol and water have been measured with an adiabatic calorimeter in the temperature range 80-350 K. These mixtures exhibited complex phase transitions in the solid state. A very broad heat capacity anomaly starting from 130 to 240 K was observed in the heat capacity curves and three transition peaks were found in this temperature range in addition to the melting peak. Experiments have demonstrated that the cooling rates had no obvious influence on the heat capacity anomaly. The thermal conductivity of the ternary systems were measured with an instantaneous heating wire conductometer in the temperature range from 233.15 to 343.15 K. All of the heat capacity and thermal conductivity results in temperature range between 221 and 350 K were correlated with temperature for practical applications.
Keywords:heat capacity;phase transition;thermal conductivity;1,2-ethanediol;ethanol;aqueous solution