Extraction of organic acids

M. Puttemans, L. Dryon, and D.L. Massart, Extraction of organic acids by ion-pair formation with tri-iV-octylamine , Anal. Chim. Acta, 1984,161, 221. 

Matsumoto, M., Mochiduki, K., Fukunishi, K., Kondo, K., Extraction of organic acids using imidazolium-based ionic liquids and their toxicity to Lactobacillus rhamnosus, Sep. Purif. Tech., 40,97-101, 2004. 

The purpose of this chapter is to discuss the use of Amberlite XAD-8 and Duolite A-7 in the field to process large volumes of water for the extraction of organic acids. Schemes involving filtration, concentration, and isolation steps for extracting organic acids from water by using XAD-8 and Duolite A-7 have been devised (9, 10). Some of the logistical problems of filtration and sample preservation are also discussed. 

Vajda M, Sabolova E, Schlosser S, and Mikulova E. Membrane-based extraction joined with membrane-based stripping in a circulating arrangement II. Extraction of organic acids. Chem Pap, 2003 57(1) 3-10. 

Wang CC and Bunge AL. Multisolute extraction of organic acids by emulsion liquid membranes. I. Batch experiments and models. J Membr Sci 1990 53 71-103. 

Schafer, A., Hossain, M. M. (1996). Extraction of organic acids from kiwifruit juice using a supported liquid membrane process. Bioprocess Biosyst. Eng., 16, 25-33. 

Chaudhuri, J.B. and Pyle, D.L. (1992). Emulsion hquid membrane extraction of organic acids. 1 A theoretical model for lactic acid extraction with emulsion swehing. Chem. Eng. Sci., 47, 41-8. 

A patent covering the concept of extraction of organic acids from high-pH solutions provides data from which the extraction efficiency of this concept can be analyzed (Shimshick, 1981). Example 6 from the patent is reproduced. 

From the data and from the experimental procedure described in the patent the overall distribution coefficient based on total acetate is calculated as 0.004. This is an extremely small number, which, of course, is a consequence of the small amount of free acid available in solution at the high pFI of the solution. Other authors (Yates, 1981 Busche, Shimshick, and Yates, 1982) address the problem of incomplete extraction of organic acids from high-pH solutions using CO2. The authors suggest that the raffinate from the extractor can be recycled to the fermentor. 

A. M. Baniel, Extraction of Organic Acids from Aqueous Solutions, U.S. Patent 4,334,095 (1989). 

For example, the extent of extraction of organic acids and bases will depend on the pH of the aqueous phase. 

A.Guvenc, N. Kapucu, U. Mehmetoglu and A. Calimli, Reactive extraction of organic acids by supercritical C02 containing tertiary amines... 

Long-chain, aliphatic amines ate effective extractants for separation of carboxylic acids from dilute aqueous solution (Yang et al., 1991). Generally, the amine extractants are dissolved in a diluent, an organic solvent that dilutes the extractant. It controls the viscosity and density of the solvent phase. In order to improve the amine s solvation power, diluents such as oleyl alcohol, chloroform, methyl isobutyl ketone, and 1-octanol have been used. The diluents affect the basicity of the amine, the stabiUty of the acid amine complex formed and its solvation power. The pH of the aqueous phase is an important parameter for the reactive extraction of organic acids (Kahya et al., 2001). In the present study, various pure diluents are used for extraction of propionic acid from aqueous solution. On the basis of distribution coefficients, reactive extraction is also carried out with amine extractant for the recovery of propionic acid. 

Chemical reactions occur in many commonly practiced separation processes. By chemical reactions, we mean those molecular interactions in which a new species results (Prausnitz et al, 1986). In a few processes, there will he hardly any separation without a chemical reaction (e.g. isotope exchange processes). In some other processes, chemical reactions enhance the extent of separation considerably (e.g. scrubbing of acid gases with alkaline absorbent solutions, solvent extraction with complexing agents). In still others, chemical reactions happen whether intended or unintended estimation of the extent of separation requires consideration of the reaction. For example, in solvent extraction of organic acids, the extent of acid dissociation in the aqueous phase at a given pH should be taken into account (Treybal, 1963, pp. 38-41). Chemical equilibrium has a secondary role here, yet sometimes it is crucial to separation. 

Sirman, T., Pyle, L., and Grandison, A. S. (1991). Extraction of organic acids using a supported liquid membrane. Biochem. Soe. Trans. 19, 274S. 

Extraction of organic acids from physiological fluids... 

Solvent extraction has the advantages of relative simplicity and rapidity and no special apparatus is required (conical centrifuge tubes are ideal, for example) unless continuous extraction techniques are used. In particular, very small amounts of physiological fluids may be extracted with this technique, although it does suffer from the disadvantageous partitioning and possible artefact formation mentioned above. However, much useful work has resulted from the use of solvent extraction of organic acids, particularly where the... 

A similar procedure is also used to extract the more hydrophobic and aromatic acids from the freeze-dried residue from the DEAE-Sephadex extract of organic acids from urine (Section 2.1.2) after re-constitution in 1-2 ml of water. This latter procedure has the advantage that all of the extracted compounds are known to be acidic in nature, and oxo acids are already stabilized as their ethoximes. 

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