Carboxylic acids, extraction

Based on the calculation of the solvatation free energy of methylene fragment with carboxyl at the aliphatic carboxylic acids extraction, the uniqueness of cloud-point phases was demonstrated, manifested in their ability to energetically profitably extract both hydrophilic and hydrophobic molecules of substrates. The conclusion is made about the universality of this phenomenon and its applicability to other kinds of organized media on the surfactant base. 

Giilapar, F. O., Buchs, A. and Susini, A. (1989) Capillary gas chromatography mass spectrometry and identification of substituted carboxylic acids extracted from a 400 year old Nubian burial. Journal of Chromatography 479, 61 72. 

Soluble loss of a reagent (extractant, modifier, or diluent) from the solvent phase is an inherent part of the solvent extraction process, since all organic compounds are soluble, to some extent, in water. The conditions prevailing in the system can also promote solubility, which can be a particular problem if the composition and properties of the aqueous phase are inflexible. For example, the solubility of alkylphosphoric acid and carboxylic acid extractants is dependent on temperature, pH, and salt concentration in the aqueous phase. 

The solubility of carboxylic acid extractants in aqueous solution is a function of temperature, pH, and salt concentration. Most of the information on the solubility of these reagents is limited to their solubility in water, and not much practical information is available on actual leach liquors and similar solutions. 

Epstein S, Krishnamurthy RV, Cronin JR, Pizzarello S, Yuen GU (1987) Unusual stable isotope ratios in amino acid and carboxylic acid extracts from the Murchison meteorite. Nature 326 477 79... 

The Sumitomo Metal Mining Co. in Japan uses a carboxylic acid extractant to recover nickel and cobalt from a solution obtained from the pressure leaching of metal sulfide concentrates with sulfuric acid.44 Iron, copper, zinc and manganese are removed from the leach liquor by conventional precipitation methods prior to the extraction of nickel and cobalt into a 40-60% solution... 

Fig. 8 Example of missed and double addition of the internal standard. Analyte clopidogrel carboxylic acid extraction evaporation-free protein precipitation sample volume 50 p.L IS volume 150 pL. Reproduced from ref. [36] with permission from Elsevier...

Other phytochemicals which exhibit JH activity include juvadecene (1-(3,4-methylenedioxyphenyI)-fraws-3-decene) isolated from roots of the pepper-tree, Macropiper excelsum Miq. [110], thujic acid (5,5-dimethyl-1,3,6-cycloheptatrien-l-carboxylic acid) extracted from the heartwood of western red cedar, Thujaplicata [111] andtagetone((E)-2,6-dimethyl-5,7-octadien-4-one) from the marigold, Tagetes minuta L. [112], There have been numerous reports of juvenoid activity of plant extracts (Table 5) however, to our knowledge, the compound(s) responsible for this activity have not been isolated and characterized. 

Co, Ni, Cu, and Pb thus, the separation of rare earths from a large amount of zinc is important. Conventional carboxylic acid extractant, Versatic 10, extracts yttrium, europium, and zinc at neutral pH and their mutual separation is difficult. On the other hand, calixarene carboxyl derivative was shown to extract rare earths at acidic pH preferentially to zinc, particularly in the presence of sodium ions in the aqueous phase. 

LINEHAN D.J. 1977. A comparison of the carboxylic acids extracted by water from an agricultural top soil with those extracted by alkali. Journal of Soil Science, 28, 369-378. 

Fig. 3. Concentration of Ci2 C32 acyclic aliphatic carboxylic acids extracted from aliquots of Lake Biwa surface sediments after isothermal heating at temperatures from 68 to 325°C for 24h. (Kawamura and Ishiwatari, 1985a)...

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