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Here is a video that demonstrates the interesting nature of the triple point of cyclohexane, so I tried researching on the internet for a phase diagram, but only found data from a manufacture where the triple point was specified as 279.48 degK at 5.388 kPa. But in the video there doesn't seem to be a cooling plate. The flask appears to be at room temperature.

What are the triple point specs for pure cyclohexane? If they match the data above, how were they able to achieve the phase transitions shown in the video at room temperature?

Also where can I find a phase diagram for pure cyclohexane on the internet?

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  • $\begingroup$ I suspect that with volatile solvents like cyclohexane, the vacuum pump you hear in that video can do a good job of cooling the flask via evaporative cooling. $\endgroup$ – Curt F. Mar 4 '15 at 5:49
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The NIST REFPROP (Reference Fluid Thermodynamic and Transport Properties) program reports the triple-point temperature of cyclohexane as 279.47 K.
The program refers to: S. G. Penoncello, R. T. Jacobsen, and A. R. H. Goodwin: “A Thermodynamic Property Formulation for Cyclohexane”, International Journal of Thermophysics, Vol. 16., No. 2, 1995, 515–531.
This publication mentions the triple-point temperature as T = 279.47 K and the triple-point pressure as p = 5.388 kPa.
The given reference is: J. G. Aston, G. J. Szasz, and H. L. Fink, J. Am. Chem. Soc. 65 1135 (1943).


The following p-T diagram (made using REFPROP) shows the melting line (solid-liquid equilibrium, blue) and the vaporization line (liquid-gas equilibrium, red), which meet at the solid-liquid-gas triple point. Unfortunately, REFPROP does not include the sublimation line for cyclohexane.

enter image description here

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