Solute extraction via supercritical ethane from poly(ethylene glycol): A Monte Carlo simulation study

The use of supercritical ethane in place of supercritical carbon dioxide for separations could allow lower operating pressures while achieving comparable or improved efficiency. To explore the viability of this alternative, the partitioning of ethylbenzene was studied between supercritical ethane and poly(ethylene glycol) (PEG) at 308.15, 328.15 and 348.15 K and 6.6, 10, 15.5 and 20 MPa with PEG-400, 600 and 900 via Monte Carlo molecular simulation. The effect of 5% n-octane as cosolvent with ethane was also studied. Results indicate that the relative solubility can be controlled with supercritical fluid density while overall solubility depends on PEG molecular weight. Preferential solvation of ethylbenzene by ethane was found to be prominent in the PEG phase and low density supercritical phases. In comparing to previous results using carbon dioxide for extraction, ethane is predicted to be comparable while requiring lower pressures.