Thermal diffusivities and sound velocities of supercritical methanol and ethanol measured by the transient grating method

We have applied the transient grating (TG) method to the measurement of the thermal diffusivities and sound velocities of supercritical methanol (MeOH ) and ethanol (EtOH) in the density region from 0.14 to 2.3, in reduced uni ts scaled by the critical density, at T = 513 and 540 K in MeOH, and T = 51 8 and 543 K in EtOH. We estimated the thermal conductivity of MeOH in the s ame density range from the thermal diffusivities and ensured that it increa ses in the medium-density region, which is similar to those of other fluids . The sound velocity does not show meaningful dispersion on the sound frequ ency from 50 to 350 MHz in the measured density region.