In the present study, we have found that the ionic liquid (IL), [TMA][EPPS], could induce liquid-liquid phase splitting in the aqueous solution of 1,4-dioxane at ambient conditions. This IL is composed of tetramethylammonium (TMA) as a cation and a biological buffer, 4-(2-hydroxyethyl)-1-piperazinepropanesulfonic acid (EPPS), as an anion. The efficiency of this buffer-based IL for separating 1,4-dioxane from its aqueous solution has been evaluated on the basis of the liquid-liquid equilibrium (LLE) and solid-liquid-liquid equilibrium (SLLE) data of 1,4-dioane + water + [TMA][EPPS] at 298.15 K and under atmospheric pressure. The experimental LLE phase boundary data were correlated with an empirical equation and the effective excluded volume (EEV) model, respectively. The consistency of the LLE tie-line data was confirmed by using the Othmer-Tobias model. The binary interaction parameters of the NRTL model for each pair were obtained by correlating the experimental LLE and SLLE tie-line data. By using [TMA][EPPS] as an auxiliary agent, the maximum concentrations of 1,4-dioxane (97.8 wt%) in the organic-rich phase is greater than the azeotropic compositions (87.82 wt%) of the corresponding aqueous system. It clearly indicates that [TMA][EPPS] can be served as a high efficiency, non-corrosive, and biocompatible green agent for recovering high purity of 1,4dioxane from its aqueous solution.
The table above is generated from the ThermoML associated json file (link above).
POMD and RXND refer to PureOrMixture and Reaction Datasets. The compound numbers are included in properties, variables, and phases, if specificied;
the numbers refer to the table of compounds on the left.