Extraction aqueous salt solutions

One problem limiting the consideration of salt extractive distillation is the fact that the performance and solubility of a salt in a particiilar system is difficult to predict without experimental data. Some recent advances have been made in modeling the X T.E behavior of organic-aqueous-salt solutions using modified UNIFAC, NRTL, UNIQUAC, and other approaches [Kumar, Sep. Sci. Tech., 28(1), 799 (1993)]. 

It has been found that the growth hormone can be obtained in crystalline form from human pituitary glands by procedures comprising (1) extraction of the fresh glands with acetone, (2) extraction of the acetone residue with aqueous salt solutions, (3) precipitation from aqueous salt solutions by the addition of suitable miscible organic solvents of alkaline and acid pH, and finally crystallization from aqueous salt solutions by the addition of suitable miscible organic solvents. 

Fig. 5. Extraction of pertechnetate from aqueous salt solutions with tri-n-butyl phosphate ...

After 36 hours the furnace is allowed to cool, the bomb is removed, cooled to dry-ice temperatures, and opened carefully as there may be residual pressure. The golden brown liquid is poured into a 200-ml. flask, and the methyl iodide is removed on a rotary evaporator (iCautionI Hood). The residue from the flask and the bomb is washed into a 500-ml. separatory funnel with 100 ml. each of ether and 1 1 solution of Claisen s alkali and water (Note 8). The funnel is shaken, and the alkali layer is removed. The ether layer is extracted four additional times with 100 ml. portions of the alkali (Note 9), washed twice with 75-ml. portions of water, once with saturated aqueous salt solution, and... 

To the cooled (20-30°) mixture is added 240 g. of sodium chloride (Note 6). The resulting mixture is extracted with three 500-ml. portions of methylene chloride. The combined organic extracts are first washed with 40 ml. of 5% aqueous sodium bicarbonate solution (Note 7), and then with 300 ml. of saturated aqueous salt solution, dried over anhydrous sodium sulfate, and the solvent is distilled under reduced pressure (35 mm.) on a water bath (60-70°). The resulting residue weighing approximately 125 g. is fractionated under reduced pressure, and the fraction boiling at 100-103° (0.8 mm.) is collected yield 104 g. (76%) (Notes 8 and 9). 

There are two basic methods for extracting gonadotropic hormones from pituitary glands (1) extraction into organic salt solutions and (2) extraction with aqueous salt solutions. 

Extraction of Humic Substances in Water and in Aqueous Salt Solutions... 

The connective tissues and liquids of HA, as a rule, exist firstly as chondroitin sulfates in association with collagen [27,28] and other glycosaminoglycans. Purification methods must therefore include the purification of HA from these impurities. An extraction of hyaluronate with water and aqueous salt solutions is accompanied with the presence of a large amount of impurities of protein nature, other polysaccharides, nucleic acids, lipids and lipoproteins. The limitation of the protein removal fermentative methods... 

In the liquid-liquid extraction procedure, the water-insoluble quaternary amnonium salt tricaprylmethylanmonlum chloride dissolved in trichlorotrifluo-roethane (Freon-TF, ClgFCCClFg b.p. 47°) was used to extract periodate from neutral aqueous salt solutions. More than 992 of the periodate appeared in the organic phase after a single extraction of an iodate-periodate sample with an equal volume of the quaternary anmonium salt-Freon solvent system >942 of the iodate remained in the aqueous phase. High concentrations of sodium chloride (0.2-0.5 afforded clear, clean phase separation. 

ISO 6843 specifies a variation of the extraction method for determination of PEG in nonionic surfactants. In this case, an aqueous salt solution of the surfactant is extracted with 9 1 ethyl acetate/l-butanol. Almost all of the ether sulfate goes into the organic phase, leaving behind PEG, PEG sulfate, and sulfate ion, as well as a small amount of the ether sulfate. Alkyl- or alkylphenol ethoxylate and alkyl- or alkylphenol sulfate are expected to partition primarily in the organic phase. The amount of anionic surfactant remaining in the aqueous phase is determined by two-phase titration, as is the equivalent weight of the extracted material (71). 

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. 

Metal carboxylates are ionic and when the molecular weight isn t too high the sodium and potassium salts of carboxylic acids are soluble m water Carboxylic acids therefore may be extracted from ether solutions into aqueous sodium or potassium hydroxide... 

Biopolymer Extraction. Research interests involving new techniques for separation of biochemicals from fermentation broth and cell culture media have increased as biotechnology has grown. Most separation methods are limited to small-scale appHcations but recendy solvent extraction has been studied as a potential technique for continuous and large-scale production and the use of two-phase aqueous systems has received increasing attention (259). A range of enzymes have favorable partition properties in a system based on a PGE—dextran—salt solution (97) ... 

The purified acid is recovered from the loaded organic stream by contacting with water in another countercurrent extraction step. In place of water, an aqueous alkafl can be used to recover a purified phosphate salt solution. A small portion of the purified acid is typically used in a backwashing operation to contact the loaded organic phase and to improve the purity of the extract phase prior to recovery of the purified acid. Depending on the miscibility of the solvent with the acid, the purified acid and the raffinate may be stripped of residual solvent which is recycled to the extraction loop. The purified acid can be treated for removal of residual organic impurities, stripped of fluoride to low (10 ppm) levels, and concentrated to the desired P2 s Many variations of this basic scheme have been developed to improve the extraction of phosphate and rejection of impurities to the raffinate stream, and numerous patents have been granted on solvent extraction processes. 

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