The reactive extractions of acetic acid, HAc, with tri-n-octylamine (TOA), Q, dissolved in three solvents with different dielectric constants (dichloromethane, butyl acetate, and n-heptane) without and with 1-octanol as phase modifier have been comparatively analyzed. The results indicated that the mechanism of the interfacial reaction between acid and extractant is controlled by the organic phase polarity. In absence of 1-octanol, the structures of the extracted complexes are HAc.Q for dichloromethane, HAc.Q 2 for butyl acetate, and (HAc) 2 Q 4 for n-heptane. These structures are modified by adding 1-octanol and become HAc.Q for extraction in dichloromethane or butyl acetate and (HAc) 2 Q 2 for extraction in n-heptane, respectively. Although the presence of 1-octanol improves the extraction efficiency, it leads to the reduction of extraction constants for lower-polar solvents, influence that is more significant for n-heptane.
This article presents the results of a comparative study of reactive extraction of succinic acid with tri-n-octylamine (TOA) dissolved in solvents with different dielectric constants (dichloromethane, n-butyl acetate, and n-heptane), with and without octan-1-ol addition as phase modifier. The positive effect of octan-1-ol on extraction efficiency was quantified by means of amplification factors. For all studied systems, the addition of octan-1-ol into the solvent phase led to an increase of extraction efficiency, the most important effect being recorded for the solvent with the lowest polarity, namely n-heptane. The maximum value of amplification factor was reached for pH ¼ 6 and indicated an increase of reactive extraction yield of about 1.26 times for dichloromethane, 1.55 times for n-butyl acetate, and 2.88 times for n-heptane.
The reactive extractions of formic acid with tri-n-octylamine (TOA) dissolved in three solvents with different dielectric constants (dichloromethane, butyl acetate, n-heptane) without and with 1-octanol as phase modifier were comparatively analyzed. The results indicated that the mechanism of the interfacial reaction between acid and extractant (Q) is controlled by the organic phase polarity. In the absence of 1-octanol, the structures of the extracted complexes are (HA) 2 Q 2 for dichloromethane and butyl acetate, and (HA) 2 Q 4 for n-heptane. These structures are modified by adding 1-octanol and become (HA) 2 Q for extraction in dichloromethane or butyl acetate, and (HA) 2 Q 2 for extraction in n-heptane. Although the presence of 1-octanol improves the extraction efficiency, it leads to a reduction of the extraction constants for all considered solvents, an influence that is more significant for n-heptane.
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