Salting-out of acetone, 1-butanol, and ethanol from dilute aqueous solutions

The salting-out phase equilibria for acetone, 1-butanol, and ethanol (ABE) from dilute aqueous solutions using potassium carbonate (K2CO3) and dipotassium hydrogen phosphate trihydrate (K(2)HPO(4)3H(2)O) as outstanding salting-out agents were investigated. Increasing the salt concentration strengthened the salting-out effects and improved the distribution coefficients of all three solvents (ABE) significantly. Temperature had a slight effect on the phase equilibria. The K2HPO4 solution (69 wt %) showed a stronger salting-out effect than the K2CO3 solution (56 wt %) on recovering ABE from dilute aqueous solutions. Dilute aqueous solutions containing more solvents increased the recoveries of acetone and 1-butanol, while the results showed a negligible effect on the solubility of ABE. The solubility of ABE was also correlated well with the molar number of salt per gram of water in the aqueous phase. A new equation demonstrated this satisfactorily. (c) 2015 American Institute of Chemical Engineers AIChE J, 61: 3470-3478, 2015