Extraction of acetic acid with tri-n-octylamine:: Physical properties and phase equilibria

The effect of sodium chloride, hydrochloric acid, and sodium acetate on the partitioning between aqueous solutions and tri-n-octylamine has been studied at 298 K. Physical properties (density, viscosity, and interfacial tension) have been determined for the salt-free systems. The equilibrium data of the simultaneous extraction of acetic acid and hydrochloric acid is described well with a model that includes the formation of organic complexes and the dissociation equilibria in the aqueous phase. The Pitzer equation was used for the aqueous phase and the Hildebrand and Scott solubility parameters were used to describe nonidealties in the organic phase.