Dependence of Extraction Equilibrium on Apparent Basicity of Extractant

Abstract

The extraction method based on reversible chemical complexation is highly effective and selective for separating polar organic solutes from dilute solutions. In this paper, trioctylamine (TOA) in 1-octanol, trialkyl phosphine oxide (TRPO), and tri-butyl-phosphate (TBP) in kerosene were selected as typical extractants. The apparent basicity of these extractants to HCl was measured. Dependences of the extraction equilibrium behavior on the apparent basicity of the extractant were investigated. Results showed that the apparent basicity of the extractant depended on extractant type and concentration. A new mathematic model was proposed, which can predict the extraction equilibrium of Lewis acid including the association driving force (∆pK a ) and the hydrophobicity of the complex. The apparent extraction equilibrium constant for various extractant systems can be predicted well by using different coefficients in the equation. The correlative equation can be used as the basic style to correlate other extraction equilibria.

Extraction of hydrogen chloride by a coupled reaction-solvent extraction process

“…Figure 4 shows that the apparent basicity of N235 in the presence of alcohols decreases with increasing N235 concentrations, i.e., the concentration of HCl. In addition, the basicity in alcohols with fewer carbon atoms was higher than those in alcohols with more carbon atoms, which is consistent with the above results and with a previous report [34]. The basicity in MIBK is relatively weak compared to that in alcohols, because of its poor solvation for the complex.…”

“…Actually, polar diluents can increase the extraction ability of amines by providing additional solvating power which allows a higher fraction of the polar acid-amine complex to stay in the organic phase. Moreover, the solvation effect of the diluents caused by the formation of hydrogen bonds between the complex and protonic polar diluents and among other compounds improves the extraction ability compared to that of the non-protonic polar diluents [22,34].…”

Lithium Enrichment of High Mg/Li Ratio Brine by Precipitation of Magnesium via Combined CO2 Mineralization and Solvent Extraction

“…Although nonpolar diluents are widely employed in many industrial processes, nonpolar diluents, for example, cyclohexane (CHA) and methyl isobutyl ketone (MIBK), resulted in poor magnesium conversions of 2.87% and 2.37%, respectively. The poor solubility of the polar extraction complex in the organic phase is in accord with the similarity-intermiscibility theory. , The alcohols exhibited the better performance in terms of mineralization of magnesium. The conversion of magnesium decreased from 65.32% (1-propanol) to 36.75% (2-ethylene­hexanol) varied with different alcohols, while the Mg/Li ratio showed an opposite trend, increasing from 6.88 (1-propanol) to 13 (2-ethylenehexanol).…”

“…The poor solubility of the polar extraction complex in the organic phase is in accord with the similarity-intermiscibility theory. 39,40 The alcohols exhibited the better performance in terms of mineralization of magnesium. The conversion of magnesium decreased from 65.32% (1propanol) to 36.75% (2-ethylenehexanol) varied with different alcohols, while the Mg/Li ratio showed an opposite trend, increasing from 6.88 (1-propanol) to 13 (2-ethylenehexanol).…”

Preparation of calcium carbonate and hydrogen chloride from distiller waste based on reactive extraction–crystallization process

“…Besides, the polar diluent could increase the power of amines by providing additional solvating power that allows a higher fraction of polar Lewis acid-amine complexes to stay in the organic phase. Moreover, the salvation effect of diluent caused by the formation of H-bonds between the complex and protonic polar diluent efficiently improves the extraction power efficiently [26]. Consequently, we selected 50% as the optimal volume fraction.…”