Salting-out extraction

Solvent Solvent Inverse Solvent evaporation extraction salting out evaporation... 

SEPARATION OF LIQUID MIXTURES. SEPARATION BY EXTRACTION. SALTING OUT... 

Sample Dissolve 50 g of corn, peanuts, or peanut butter in an aqueous methanol extractant. Salt out the aflatoxins and extract into chloroform. Evaporate to dryness and reconstitute in 3 mL of methylene chloride. 

After numerous tedious repetitions of precipitation, extraction, salting out, and further extraction, a powder that was a protein in nature was obtained. 

The constant K is termed the distribution or partition coefficient. As a very rough approximation the distribution coefficient may be assumed equal to the ratio of the solubilities in the two solvents. Organic compounds are usually relatively more soluble in organic solvents than in water, hence they may be extracted from aqueous solutions. If electrolytes, e.g., sodium chloride, are added to the aqueous solution, the solubility of the organic substance is lowered, i.e., it will be salted out this will assist the extraction of the organic compound. 

In the isolation of organic compounds from aqueous solutions, use is frequently made of the fact that the solubility of many organic substances in water is considerably decreased by the presence of dissolved inorganic salts (sodium chloride, calcium chloride, ammonium sulphate, etc.). This is the so-called salting-out effect. A further advantage is that the solubility of partially miscible organic solvents, such as ether, is considerably less in the salt solution, thus reducing the loss of solvent in extractions. 

The high sodium ion concentration results in facile crystallisation of the sodium salt. This process of salting out with common salt may be used for recrystallisation, but sodium benzenesulphonate (and salts of other acids of comparable molecular weight) is so very soluble in water that the solution must be almost saturated with sodium chloride and consequently the product is likely to be contaminated with it. In such a case a pure product may be obtained by crystallisation from, or Soxhlet extraction with, absolute alcohol the sul-phonate is slightly soluble but the inorganic salts are almost insoluble. Very small amounts of sulphones are formed as by-products, but since these are insoluble in water, they separate when the reaction mixture is poured into water ... 

Metal chlorides which are not readily salted out by hydrochloric acid can require high concentrations of HCl for precipitation. This property is used to recover hydrogen chloride from azeotropic mixtures. A typical example is the calcium chloride [10043-52-4] addition used to breakup the HCl—H2O azeotrope and permit recovery of HCl gas by distillation (see Distillation, azeotropic and extractive). 

The extent of extraction can be increased by a salting out effect. The selectivity of TBP is very poor compared with HDEHP and it is only useful for light rare-earth separation however, organic phase loadings or REO higher than 100 g/L can easily be achieved. There are a large number of TBP manufacturers in Japan, the United States, and Europe. 

The method of extraction of Ru(III) from thiocyanate solutions by water soluble extractants in the presence of ammonium sulfate as salting out agent followed by photometric determination of it in extract has been elaborated. 

Because phenols are weak acids, they can be freed from neutral impurities by dissolution in aqueous N sodium hydroxide and extraction with a solvent such as diethyl ether, or by steam distillation to remove the non-acidic material. The phenol is recovered by acidification of the aqueous phase with 2N sulfuric acid, and either extracted with ether or steam distilled. In the second case the phenol is extracted from the steam distillate after saturating it with sodium chloride (salting out). A solvent is necessary when large quantities of liquid phenols are purified. The phenol is fractionated by distillation under reduced pressure, preferably in an atmosphere of nitrogen to minimise oxidation. Solid phenols can be crystallised from toluene, petroleum ether or a mixture of these solvents, and can be sublimed under vacuum. Purification can also be effected by fractional crystallisation or zone refining. For further purification of phenols via their acetyl or benzoyl derivatives (vide supra). 

Anthraquinone Blue B (Acid Blue 45, l,5-diamino-4,8-dihydroxy-9,10-anthraquinone-3,7-disulfonic acid di-Na salt) [2861-02-1] M 474.3, m >300°, Cl 63010, X.max 595nm, pKesi(1) <0, pKEst(2) 2, pKEst(3) 9. Purified by salting out three times with sodium acetate, followed by repeated extraction with EtOH [McGrew and Schneider 7 Am Chem Soc 72 2547 1950]. 

Anthraquinone Blue RXO [4403-89-8] M 445.5. Purified by salting out three times with sodium acetate, followed by repealed extraction with EtOH [McGrew and Schneider J Am Chem Soc 72 2547 1950]. 

Milling Red SWB l-[4-[4-[4-toluenesulfonyloxy]phenylazo](3,3 dimethyl-l,l -biphenyl)-4 -azo]-2-hydroxynaphthalene-6,8-disulfonic acid di-Na salt, Acid Red 114 [6459-94-5] M 830.8, m dec >250", Cl 23635, X,max 514nm. Salted out three times with sodium acetate, then repeatedly extracted with EtOH. [McGrew and Schneider J Am Chem Soc 72 2547 1950.] See Solochrome Violet R on p. 352 in Chapter 4. 

The aqueous alkaline extract is heated to ioo° to remove ether and volatile impurities. The solution is then cooled with ice and acidified with 25 per cent sulfuric acid, and the organic acid separated. The water layer is distilled from a 2-1. flask until no more oily solution comes over, The distillate is saturated with salt and the acid layer is separated. This water layer together with the low boiling fraction from distillation of the crude trimethylacetic acid is distilled and the distillate salted out as before. 

Sometimes mixed solvents may be used to improve the above properties. Salting-out agents may also improve extractability. 

Procedure. Prepare four test solutions of phenol by placing 200 mL of boiled and cooled distilled water in each of four stoppered, 500 mL bottles, and adding to each 5g of sodium chloride this assists the extraction procedure by salting out the phenol. Add respectively 5.0, 10.0, 15.0 and 20.0 mL of the standard phenol solution to the four bottles, then adjust the pH of each solution to about 5 by the careful addition of 5M hydrochloric acid (use a test-paper). Add distilled... 

All efforts of trying to extract the sodium salt into an organic solvent were unsuccessful, and, thus, a salting out procedure using the common ion effect was used. The product at this stage is in the aqueous phase and addition of 15 g of sodium chloride /100 mL of the reaction mixture, completely precipitates all the coupled sodium salt which is filtered. The filtered crude product is dewatered by washing with isopropyl alcohol or drying under vacuum. The mother liquors... 

Bouvier, C. Cote, G. Cierpiszewski, R. Szymanowski, J. Influence of salting-out effects temperature and the chemical structure of the extractant on the rate of copper(II) extraction from chloride media with dialkyl pyridine dicarboxylates. Solvent Extr. Ion Exch. 1998, 16, 1465-1492. 

Almost simultaneously, a pectinesterase was isolated from tomatoes of the Immuna variety.97 After extraction with 2% sodium chloride at pH 7.8, and fractional salting-out with ammonium sulfate, chromatography on DEAE-Sephadex A-50 removed a substantial proportion of colored contaminants and accompanying acid compo-... 

Delincee and Radola100 used a commercial preparation, as well as fresh tomatoes, for the preparation, purification, and characterization of tomato pectinesterase. The tomatoes were pressed and then homogenized directly with ammonium sulfate at 70% saturation. The precipitate obtained was extracted with 0.3 M phosphate and repeatedly salted out with ammonium sulfate, and the product was separated on a column of Sephadex G-75. The pattern of separation was similar to that in preceding work.50,97 A detailed study of the size properties of pectinesterase was conducted by gel-filtration and sedimentation analysis.100 By column and thin-layer gel-filtration on Sephadex G-75, the approximate molecular weight of a number of preparations of tomato pectinesterase was determined, values of 24,000 and 27,000 being obtained. A possible interaction of the... 

Fig. 4. — Monitoring of the Multiple Molecular Forms of Tomato Pectinesterase by Starch-gel Electrophoresis.98 [ENZ, detection of pectinesterase activity by paper print with pectin and Bromothymol Blue PROT, protein staining with nigrosin O, origin. Key A, 1 crude tomato extract after ammonium sulfate salting-out, and dialysis 2 pectinesterase fraction from column of DEAE-Sephadex A-50 3 and 4 pectinesterase fractions from column of Sephadex G-75. B, Two parts of the same gel after horizontal slicing 1, 500 fig of the isolated form of pectinesterase from a column of CM-Seph-adex C-50 with 175 mM phosphate-sodium chloride buffer 2, active fraction at 150 mM buffer 4 and 5, 250 fig and 1 mg of the isolated form of pectinesterase, respectively.]...

In a study of the pectinesterase from bananas,64,85,102 three pectinesterase fractions were obtained after respective extraction with water, 150 mM sodium chloride, and 150 mM sodium chloride of pH 7.5. The fractions obtained were further purified by fractional salting-out with ammonium sulfate, and chromatography on columns of DEAE- and CM-cellulose. A 50-fold purification was achieved, and the individual, purified fractions were characterized with respect to different effects of cations, inhibition by sucrose, and reaction kinetics. 

In the purification of pectinesterase from the fruits of Citrus nat-sudaidai,61 fractional salting-out with ammonium sulfate was followed by chromatography on a column of DEAE-cellulose and by separation of the active fraction on Sephadex G-100. A preparation (purified solution) having a specific activity 460-fold greater than that of the original extract was obtained. Its homogeneity was checked by disc electrophoresis, and its amino acid content was determined and fundamental, kinetic data were obtained. 

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