Liquid–Liquid Equilibrium of Alcohols + Ammonium/Potassium/Sodium Acetate + Water Systems: Experimental and Correlation

Abstract

Liquid–liquid equilibra of alcohol + acetate salt + water systems—namely, 2-butanol + ammonium acetate + water, 1-propanol + sodium/potassium acetate + water, and 2-propanol + sodium/potassium acetate + water systems—were successfully determined. The ability of acetate salt to form aqueous two-phase system (ATPS) with alcohol was found to be mainly driven by a high Gibbs energy (i.e., greater than −1000 kJ/mol). The fitting of the experimental binodal data was done by using the Merchuk equations. The tie-line data were satisfactorily correlated by the Othmer–Tobias and Bancroft equations. The salting-out strength of the acetate salts was evaluated based on the effective excluded volume theory and the Setschenow-type equation. The phase-forming abilities of the investigated alcohols were in the order of 2-butanol > 1-propanol > 2-propanol. For 2-propanol + acetate salt + water systems, the salting-out strength of sodium acetate was greater than that of potassium acetate. In contrast, for 1-propanol + aceta...