Application of MOSCED and UNIFAC to Screen Hydrophobic Solvents for Extraction of Hydrogen-Bonding Organics from Aqueous Solution

Abstract

Liquid−liquid extraction using hydrophobic extraction solvents is a technology well-suited to the removal of certain hydrogen-bonding organics from water or brine. Even when distillation is technically feasible, extraction might allow a significant reduction in energy consumption depending on the specific application. Various methods are available for estimating the partition ratio (K) to assess technical feasibility; however, these methods often provide only rough approximations because of the complexity of hydrogen-bonding interactions in solution. To better understand the application of the MOSCED and standard UNIFAC activity-coefficient prediction methods for screening extraction solvents, calculations were compared with K data for the extraction of propylene glycol n-propyl ether (PnP), a model hydrogen-bonding compound. Estimates of limiting activity coefficients for PnP dissolved in the organic phase (γ∞PnP,organic) obtained using MOSCED and UNIFAC are shown to be highly correlated with K data for ...