Liquid−Liquid Equilibria of Butyric Acid in Water + Solvent Systems with Trioctylamine as Extractant

Abstract

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.

Extraction of lactic acid by phosphonium ionic liquids

“…Monobasic carboxylic acids usually form in reactive extraction complexes containing a variable number of acid molecules and only one molecule of extractant, the so called (p, 1) complexes. This has been found, for example in the extraction of carboxylic acids by trialkylamines [30,31]. Based on the data presented in this paper, as discussed in Section 4.2, the formation of stoichiometrically defined (p, 1, 2) complexes with the structure (LAH) p (IL)(H 2 O) 2 is suggested where p is from the interval from 1 to 3.…”

Optimization and Evaluation of Organic Acid Recovery from Kraft Black Liquor Using Liquid-Liquid Extraction

“…Studies have shown that a solvent can successfully extract acetic acid from an aqueous solution to an organic phase by liquid-liquid extraction (LLE) [14]. The partition coefficients for these systems vary between 3 and 5 [14][15][16][17]. Senol [16] deduced a molar loading of greater than one for carboxylic acids removal from water by alamine 336 in halogenated hydrocarbon diluents.…”

Recovery of Acetic Acid from An Ethanol Fermentation Broth by Liquid-Liquid Extraction (LLE) Using Various Solvents

“…Organophosphorus compounds and alkylamines with high molecular weight, dissolved in various diluents, have been explored for liquid-liquid extraction (LLE) of acetic acid from dilute aqueous solution. The partition coefficients for these systems vary between 3 and 5 [17,[18][19][20][21]. A molar loading of greater than one was deduced by Senol [19] the removal of carboxylic acids from water using alamine 336 in halogenated hydrocarbon diluents.…”