Mathematical model of extraction of citric acid with amine

• Published in: Chemical engineering science 1992, Vol.47 (6), p.1433-1440
• Main Authors: Biźek, V., Horáček, J., Koušová, M., Heyberger, A., Procházka, J.
• Format: Article
• Language: English
• Subjects: Chemistry; Exact sciences and technology; Kinetics and mechanisms; Organic chemistry; Reactivity and mechanisms
• ISSN: 0009-2509; 1873-4405
• DOI: 10.1016/0009-2509(92)80288-N

Various mathematical models of amine extraction of tribasic weak acid were developed and compared with equilibrium data on the distribution of citric acid between water and solution of trialkylamine in MIBK. It has been found that the two suggested mechanisms of extraction (distribution of non-dissociated portion of acid × distribution of dissociated portion of acid) are equivalent, as far as the fit of the model is concerned the only difference being in the values of equilibrium constants. Two amine : acid complexes in the organic phase have been assumed (1 : 1, 2 : 1), their hydration numbers being 4 and 1, respectively. The non-ideality of the aqueous phase was neglected in the concentration range of interest. The non-ideality of the organic phase was expressed both in terms of aggregation and hydration (exponential correction using hydration numbers). The best fit was obtained using a combination of the aggregation and hydration corrections.