The Thermal Conductivity and Thermal Diffusivity of Liquid n-Alkanes: C n H2n+2 (n=5 to 10) and Toluene

Experimental values of the thermal conductivity λ and the thermal diffusivity κ of six pure liquid n-alkanes (C n H2n+2; n=5 to 10) and toluene are presented 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 T λ and T κ (associated with both λ and κ) 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 [κ=λs/(c p ρ)s] at 298.15 K calculated from the volumic heat capacity (c p ρ)s as a reference material for heat capacity and the experimentally obtained thermal conductivity λs. 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 k p =2; p=95%).