Modeling phase behavior of poly(ethylene glycol) in supercritical fluids

초록

The phase behavior of poly(ethylene glycol) (PEG) in supercritical solvents such as CO2, propylene, and butene, and in aqueous solution at high pressure are described using the perturbed chain statistical associating fluid (PC-SAFT) model. The effects of the molecular weight of PEG, solvent, pressure, and temperature are investigated. To model the phase behavior of PEG in supercritical solvents, the molecular weight- and temperature-dependence of the binary interaction parameter k(ij) is considered. In addition, modeling of a PEG/CO2/ethanol mixture was carried out. The CO2 molecule was considered as a Lewis acid, and can undergo hydrogen bonding with PEG (forming a PEG-CO2 complex) and ethanol. These cross-associations, as well as the self-association of ethanol, are described in the PC-SAFT model. The correlated pressure and temperature (P-T) isopleth curves show a somewhat difference for binary system at low temperature area (<410 K), but is consistent with experimental trend for binary and ternary system. (C) 2019 Elsevier B.V. All rights reserved.

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