Thermal Conductivity and Thermal Diffusivity of Twenty-Nine Liquids: Alkenes, Cyclic (Alkanes, Alkenes, Alkadienes, Aromatics), and Deuterated Hydrocarbons

Abstract

Experimental values of the thermal conductivity λ and thermal diffusivity a of 29 pure substances are presented in the temperature range of −15 °C to 65 °C under atmospheric or saturation pressure. The materials measured were as follows: alkenes (1-pentene, 1-hexene, 1-heptene, 1-octene, 2,3-dimethyl-1-butene, 2,3-dimethyl-2-butene), cycloalkenes (cyclopentene, cyclohexene), cycloalkanes (cyclopentane, cyclohexane, methylcyclopentane, cycloheptane, cyclooctane), aromatics and their relatives (benzene, ethylbenzene, o-, m-, and p-xylenes, propylbenzene, isopropylbenzene, hemimellitene, pseudocumene, mesitylene, 1,3-cyclohexadiene, 1,4-cyclohexadiene, bicyclo[2.2.1]hepta-2,5-diene [norbornadiene]), and deuterated hydrocarbons (benzene-d6, cyclohexane-d12, toluene-d8). Measurements were made with the transient hot-wire method in the manner previously presented, and the thermal diffusivity values were corrected by reference to the heat capacity of heptane as a reference material. Heat capacities (volumic, cpρ; massic, cp; molar, Cm,p) were complementally derived from the relationship cpρ = λ/a, with values for the density and the molar mass. 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 of kp = 2; p = 95%), although that of λ (not of a) is possibly inferior for a few substances containing slightly more impurities (i.e., mainly other isomers).