Vapor–Liquid Equilibrium Study of Binary Mixturesof Chloroform, 2‑Ethylhexanoic Acid, and Propylene Glycol MethylEther at Atmospheric Pressure

To separate the minimum-boiling azeotrope (propylene glycol methyl ether + water) in the production process of propylene glycol methyl ether, two extractive agents of chloroform and 2-ethylhexanoic acid were selected. The isobaric vapor-liquid phase equilibrium (VLE) data for three systems (chloroform + 2-ethylhexanoic acid), (propylene glycol methyl ether + 2-ethylhexanoic acid), and (chloroform + propylene glycol methyl ether) were measured at 101.3 kPa. Thermodynamic consistency of the measured VLE data was validated by the Herington and van Ness tests. The measured VLE data were well fitted with Hayden-O'Connell (HOC) thermodynamic models: nonrandom two-liquid-HOC, Wilson-HOC, and universal quasichemical-HOC with regressed parameters, respectively.