Liquid-liquid equilibrium data of butyric acid in the systems water + solvent with tri-n-octylamine as extractant and n-alkanes as diluent, and water + pure n-alkanes are presented. The distribution coefficient is a linear function of the aqueous concentration of butyric acid for pure n-alkanes. For solvents containing trioctylamine, the dependence of the distribution coefficient of butyric acid goes through a maximum at a concentration of butyric acid of about 0.2 kmol‚m -3 . An overloading of the extractant reaching the value of almost 6 was observed. The loading is independent of the extractant concentration. The experimental data were interpreted by a chemical reaction mechanism and a related model in which the existence of (1,1) to (7,1) acid-amine complexes and a monomer and a dimer of butyric acid in the solvent was supposed. The equilibrium constants of formation of these complexes and the distribution of individual species in the solvent were estimated. This model fits experimental equilibrium data well. With increasing temperature, the value of the distribution coefficient of butyric acid decreases. Coextraction of water in the solvents is proportional to the concentration of butyric acid, and in the solvent with trioctylamine, it is 10 times higher than that in pure n-alkanes.

No abstract

No abstract

No abstract