Thermal conductivity of ionic liquids under pressure

Abstract

Thermal conductivity of eight ionic liquids has been measured in the temperature and pressure intervals (288.15–313.15) K and (0.1–65) MPa, selected to have a common ion. Values within the interval (0.12–0.2) W·m−1·K−1 are found for these compounds. Thermal conductivity decreases with temperature and increases with pressure for all ionic liquids. The experimental results are compared with literature data, obtaining satisfactory agreement. The thermal conductivity data are discussed by taking into account the chemical nature of the compounds. The Bridgman equation and a heuristic modification of the Enskog theory are applied to quantitatively analyze the experimental data. This theoretical analysis is extended to other compounds to get a wider picture and thus, elucidate the main factors that could affect the thermal conductivity of ionic liquids. Finally, the prediction capability of these two theoretical approaches is evaluated using the reported thermal conductivity data.