The Thermal Conductivity and Thermal Diffusivity of Liquid n-Alkanes: CnH2n+2 (n=5 to 10) and Toluene

Experimental values of the thermal conductivity l and the thermal diffusivity o of six pure liquid n-alkanes (CnH2n+2; n=5 to 10) and toluene are preseInted in the temperature range of −20 to 70°C under atmospheric or saturation pressure. Measurements were made with the transient hot-wire method, and in the analysis, the temperatures Tl and To (associated with both l and o) were used. In the present work, the values of thermal diffusivity were corrected by the factors kf (=1.0076 to 0.9892) for data sets obtained with different configurations of the experiment, in which the factors were determined by reference to the thermal diffusivity of n-heptane [o=ls/(cpr)s] at 298.15 K calculated from the volumic heat capacity (cpr)s as a reference material for heat capacity and the experimentally obtained thermal conductivity ls . The uncertainty of the data is estimated to be 0.48% for the thermal conductivity (absolutely measured) and about 1.8% for the thermal diffusivity (with a coverage factor of kp=2; p=95%).