Thermodynamics Research Center / ThermoML | Journal of Chemical and Engineering Data

ABSTRACT

Experimental values of the thermal conductivity O and thermal diffusivity ? of sixteen pure branched alkanes (CnH2n+2; n ) 6 to 8) are presented in the temperature range -15 0C to 70 0C under atmospheric or saturation pressure. Measurements were made with the transient hot-wire method, and in the analysis, the temperatures TO and T? (associated with both O and ?) were used. The thermal diffusivity values are corrected by the factors kf ()1.0076 to 0.9892), which are determined by reference to the heat capacity (at 298.15 K) of heptane as a reference material, for data sets obtained with different configurations of the experiments. Heat capacities [volumic, cpF; specific, cp; and molar, Cm,p] are derived from the relationship cpF ) O/?, with values for the density and the molar mass. The relevance of these thermal properties to the boiling point, density, molar density, and velocity-of-sound is examined, together with the results of normal alkanes (n ) 6 to 8) and isopentane. The uncertainty of the data is estimated to be 0.4% for the thermal conductivity (absolutely measured) and about 1.8% for the thermal diffusivity (with a coverage factor kp ) 2; p ) 95%), although that of O (not for ?) is possibly inferior for a few substances containing a little larger impurity (i.e. mainly other isomers).