Measurements and thermodynamic modeling of liquid–liquid equilibria in ternary system 2-methoxy-2-methylpropane + p-cresol + water

Liquid–liquid equilibrium (LLE) data for the ternary system 2-methoxy-2-methylpropane (methyl tert-butyl ether) + p-cresol + water was measured at atmospheric pressure and temperatures of 298.15 K and 313.15 K. From the distribution coefficients and selectivity, it was found that 2-methoxy-2-methylpropane is an efficient solvent to extract p-cresol from wastewater. The consistency of the experimental tie-line data was verified with the Hand and Bachman equations. These data were also correlated with the non-random two liquid (NRTL) and universal quasi-chemical correlation activity coefficient (UNIQUAC) models to yield binary interaction parameters for p-cresol extraction process evaluation. Both models agreed with experiments very well, yet the NRTL model showed even smaller average deviation than the UNIQUAC model.

The graphical abstract shows the corresponding phase behavior for the ternary system: 2-methoxy-2-methylpropane + p-cresol + water at both 298.15 K and 313.15 K. The points in black represent temperature of 298.15 K, while the ones in red represent temperature of 313.15 K. We can also find that the solubility of p-cresol and 2-methoxy-2-methylpropane in water are so small that the left points almost coincide, which also indicates big distribution coefficient (D) of p-cresol extraction because the p-cresol in the organic phase is much more than in the aqueous phase. The result shows that 2-methoxy-2-methylpropane has promising potential to serve as a solvent to extract p-cresol from wastewater. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)Figure optionsDownload as PowerPoint slide