Thermal Conductivity, Heat Capacity and Phase Diagram of Tetrahydrofuran Under Pressure

Abstract

The thermal conductivity, Λ, and the heat capacity per unit volume, pc_p , have been measured for tetrahydrofuran (THF) using the transient hot-wire method in the temperature range 130-300 K and at pressures up to 2 GPa. Most of the data relate to the single solid phase which was found to exist over these ranges of the variables. The liquidus curve was determined roughly up to the maximum pressure, and we estimated the density of the solid phase at the normal melting point using the Clausius-Clapeyron relation. We inferred from the measurements that solid THF was a normal crystal phase in which three-phonon umklapp processes provided the only significant source of thermal resistivity. There was evidence for the effect of thermal expansion on Λ, and this effect decreased under pressure.