Phase Equilibrium of the Propylene Glycol–Propane/Butane Binary System

The phase equilibrium of the propylene glycol–propane/butane system and the solubility of propylene glycol in a supercritical propane-butane mixture at temperatures of 403, 423, and 443 K are studied using a high-pressure optical cell. The results are described using the Peng–Robinson equation of state and the Mukhopadhyay and Rao mixing law.