A DIFFERENTIAL CALORIMETRIC TECHNIQUE FOR HEAT-CAPACITY AND THERMAL-CONDUCTIVITY MEASUREMENTS OF LIQUIDS

Details are reported for a differential calorimetric technique to measure both the heat capacity and the thermal conductivity of liquid samples. The accuracy of the measured heat capacity is better than 0.4%, while sensitivity is about 4×10-4 J/°C. The accuracy of the measured thermal conductivity kL is about 1% if the difference between the kL value of the reference and the sample liquid is within 40%. Measurements were performed on: (a) water+t-butanol, (b) water+n-butanol, and (c) methanol+t-butanol mixtures at 25°C. The experimental results for solute molar fraction x less than 0.2 are compared with data in the literature in the case of water+t-butanol mixtures. The heat capacity and thermal conductivity data versus x are probably the first ones published for mixtures (b) and (c).