DISTRIBUTION OF BINARY-MIXTURES OF CITRIC, ACETIC AND OXALIC-ACID BETWEEN WATER AND ORGANIC SOLUTIONS OF TRI-N-OCTYLAMINE PART III - ORGANIC-SOLVENT CHLOROFORM

In this series of publications, the influence of the organic solvent o n the liquid-liquid equilibrium in organic/aqueous two-phase systems c ontaining a tertiary amine (tri-n-octylamine) and binary mixtures of c arboxylic acids (acetic, oxalic and citric acid) was studied. This thi rd part deals with chloroform as organic solvent while toluene and met hylisobutylketone were investigated in the previous parts. Experimenta l results for the liquid-liquid equilibrium are presented and compared to model predictions. All model parameters were determined from exper imental results for pure components and subsystems. When a mixture of citric and oxalic acid is extracted the predicted partitioning of the acids agrees quantitatively with the experimental results. However, wh en acetic acid is extracted together with citric or oxalic acid experi mental distribution ratios are higher than predicted. Quantitative agr eement is achieved by assuming the formation of mixed acid complexes ( i.e., complexes containing two different acids). (C) 1998 Elsevier Sci ence B.V. All rights reserved.