N-[tris(hydroxymethyl)methyl]-3-aminopropanesulfonic acid (TAPS) effect on the separation of carboxylic acids (acetic acid, propionic acid, or lactic acid) from their aqueous solutions using methyl isobutyl ketone as extraction solvent

This study focusses on N-[tris(hydroxymethyl)methyl]-3-aminopropanesulfonic acid (TAPS) biological buffer effect on the separation of three carboxylic acids (acetic acid, propionic acid, or lactic acid) from aqueous so-lutions using methyl isobutyl ketone (MIBK) as extraction agent. Liquid-liquid equilibria data were measured for the mixtures of water + acetic acid + MIBK + TAPS, water + propionic acid + MIBK + TAPS, and water + lactic acid + MIBK + TAPS at T = 298.15 K and 308.15 K under P = 0.1 MPa. MIBK with 5 wt% TAPS biological buffer was found to substantially increase the distribution coefficient (D) and the separation factor (S) for the extraction of carboxylic acids (acetic acid, propionic acid or lactic acid). The LLE data reveal that the order of extraction performance follows propionic acid > acetic acid > lactic acid. The NRTL model accurately represents the LLE behavior for these quaternary systems, with the root mean square deviations (RMSDs) 0.3 %. The COSMO-SAC model was also applied to correlate the LLE data, the deviations between predicted and experimental values were in the range of 7.41 %-16.98 %.