Separation and extraction process are often applied in industries. Liquid-liquid equilibrium data are needed for rational design and optimal separation operation. The objective of this study is to determine liquid-liquid equilibrium (LLE) and solid-liquid-liquid equilibrium (SLLE) data for ternary systems of acetonitrile, acetone, 1-propanol, 2-propanol, tert-butanol, 1,3-dioxolane, 1,4-dioxane, or tetrahydrofuran + water + MOPS (3-(N-morpholino)propane sulfonic acid) or MOPS sodium salt (3-(N-morpholino)propanesulfonic acid sodium salt) as biological buffer at 298.2 K under atmospheric pressure. Buffer precipitation method (buffering-out) may be used to recover organic solvents from their aqueous solutions. Two liquid phases were formed after adding a certain amount of MOPS or MOPS sodium salt in the aqueous solutions. The solubility of MOPS is higher than that of MOPS sodium salt in the aqueous solutions. However, MOPS sodium salt may be more useful for industries than MOPS, since with the lower amount of solid (buffer) added into the solutions MOPS sodium salt can give higher content of organic solvent in organic-rich phase at SLLE condition. The effective excluded volume (EEV) values of buffers were obtained from the LLE phase boundary data and tie-line data. The reliability of the experimental tie-line data was satisfactorily ascertained by the Othmer-Tobias correlation. The experimental LLE tie-line data were also accurately correlated with the NRTL model.

Separation and extraction process are often applied in industries. Liquid-liquid equilibrium data are needed for rational design and optimal separation operation. The objective of this study is to determine liquid-liquid equilibrium (LLE) and solid-liquid-liquid equilibrium (SLLE) data for ternary systems of acetonitrile, acetone, 1-propanol, 2-propanol, tert-butanol, 1,3-dioxolane, 1,4-dioxane, or tetrahydrofuran + water + MOPS (3-(N-morpholino)propane sulfonic acid) or MOPS sodium salt (3-(N-morpholino)propanesulfonic acid sodium salt) as biological buffer at 298.2 K under atmospheric pressure. Buffer precipitation method (buffering-out) may be used to recover organic solvents from their aqueous solutions. Two liquid phases were formed after adding a certain amount of MOPS or MOPS sodium salt in the aqueous solutions. The solubility of MOPS is higher than that of MOPS sodium salt in the aqueous solutions. However, MOPS sodium salt may be more useful for industries than MOPS, since with the lower amount of solid (buffer) added into the solutions MOPS sodium salt can give higher content of organic solvent in organic-rich phase at SLLE condition. The effective excluded volume (EEV) values of buffers were obtained from the LLE phase boundary data and tie-line data. The reliability of the experimental tie-line data was satisfactorily ascertained by the Othmer-Tobias correlation. The experimental LLE tie-line data were also accurately correlated with the NRTL model.

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