An Ultrasonic Method for the Accurate Determination of the Melting Line: Data for Cyclohexane and Benzene

The p‐T melting curves of cyclohexane and benzene were measured accurately at pressures up to 85 MPa and 175 MPa respectively using an ultrasonic method. Important features of this new method are that the phase transition is studied by monitoring changes in the attenuation of ultrasonic echoes and that the measurements start in a non‐equilibrium two‐phase region, the partially solidified liquid, created by superpressing the liquid sample. The accuracy of the experimental melting temperatures for both liquids is about 0.03 K. The Simon‐Glatzel equation, fitted to the experimental data, can be extrapolated to 500 MPa without introducing large errors.