Isothermal vapor–liquid equilibria for binary mixtures of carbon dioxide with diethylene glycol (diethyl, butyl, hexyl, or dibutyl) ether at elevated pressures

Isothermal vapor–liquid equilibrium (VLE) phase compositions were measured for four binary systems of carbon dioxide with diethylene glycol diethyl ether, diethylene glycol butyl ether, diethylene glycol hexyl ether, and diethylene glycol dibutyl ether at temperatures from 333.15 to 413.15 K and pressures up to 20 MPa. The saturated vapor composition of the ethers follows the order of diethylene glycol diethyl ether>diethylene glycol butyl ether>diethylene glycol dibutyl ether>diethylene glycol hexyl ether, while the solubility of carbon dioxide in the liquid obeys the sequence of diethylene glycol diethyl ether≈diethylene glycol dibutyl ether>diethylene glycol hexyl ether ≈ diethylene glycol butyl ether. Henry’s constants were calculated by fitting the Krichevsky–Ilinskaya (KI) equation to the isothermal equilibrium data. The constants increase with increasing temperature for each binary system. The new phase equilibrium data were correlated with several cubic equations of state with the van der Waals one-fluid mixing rules. Generally the Peng–Robinson (PR) equation of state with two binary interaction parameters yielded the best results.