Phase diagram under pressure

In industrial practice the solubility of substances in liquid solvents at temperatures above the boiling point, in fluidified or in supercritical gases is of great importance.
For the determination of the solubility or of the general phase behavior a pressure cell with sapphire windows is available, where the miscibility can be established.
The Figure shows an example of the solubility of polyethylene in n-hexane at a temperature range of 130°C up to 270°C and at pressures between 20 and 60 bar.

 

Phase diagram of polyethylene as a function of temperature and pressure