Thermodynamic Properties of Compressed Liquid Methanol in the Vicinity of the Freezing Line

Abstract

We present direct measurements of the isothermal compressibility (κT) and thermal expansion coefficient (αp) of liquid methanol using an expansion technique. The measurements of κT were carried out along six isotherms from (208.17 to 298.16) K at pressures up to 101 MPa. For αp, we have measured four isobars from (0.59 to 80.03) MPa from 195 K up to 300 K. Our experimental results of αp(T) for the 0.59 MPa isobar exhibit a minimum around 224 K. A clear shift of the minimum to higher temperatures is observed as the pressure increases along the different isobars. Interestingly, the minima for the isobars of αp(ρ) take place within a narrow range of densities, around 26.5 mol·dm-3 (about 3.15 times the critical density).