The thermal conductivity and thermal diffusivity of liquid n-alkanes: CnH2n+2 (n=5 to 10) and toluene

Experimental values of the thermal conductivity lambda and the thermal diffusivity kappa of six pure liquid n-alkanes (CnH2n+2; n=5 to 10) and toluene are presented in the temperature range of -20 to 70degreesC under atmospheric or saturation pressure. Measurements were made with the transient hot-wire method, and in the analysis, the temperatures T-lambda and T-kappa (associated with both lambda and kappa) were used. In the present work, the values of thermal diffusivity were corrected by the factors k(f) (=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 [kappa=lambda(s)/(c(p)rho)(s)] at 298.15 K calculated from the volumic heat capacity (c(p)rho)(s) as a reference material for heat capacity and the experimentally obtained thermal conductivity lambda(s). 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%).