Extraction salt formation

The older methods have been replaced by methods which require less, if any, excess sulfuric acid. For example, sulfonation of naphthalene can be carried out in tetrachloroethane solution with the stoichiometric amount of sulfur trioxide at no greater than 30°C, followed by separation of the precipitated l-naphthalenesulfonic acid the filtrate can be reused as the solvent for the next batch (14). The purification of 1-naphthalenesulfonic acid by extraction or washing the cake with 2,6-dimethyl-4-heptanone (diisobutyl ketone) or a C-1—4 alcohol has been described (15,16). The selective insoluble salt formation of 1-naphthalenesulfonic acid in the sulfonation mixture with 2,3-dimethyl aniline has been patented (17). 

By structural complementarity, dicationic l,4-diazabicyclo[2.2.2]octane (VII) provides an appropriate recognition site for phosphate ions and two stearyl side chains attached to the amines add lipophilic properties 59,60). Such a carrier model can selectively extract nucleotides from aqueous solution to chloroform solution via lipophilic salt formation. The order of nucleotide affinity is ATP > ADP > AMP. The selectivity ratios were 45 for ADP/AMP and 7500 for ATP/AMP at pH 3. The relative transport rate was ATP > ADP > AMP. The ratios were 60 for ATP/AMP and 51 for ADP/AMP. The modes of interaction of ADP and ATP are proposed to be as shown in Fig. 6. 

SYNTHESIS A solution of 11.5 g pellet KOH (85%) in 75 mL EtOH was treated with 25 g sesamol followed by 27 g methyl iodide. This was brought to reflux on the steam bath. Salt formation was apparent in 20 min, and refluxing was maintained for atotal of 4 h. The solvent was removed under vacuum, and residue poured into 400 mL H,0. This was acidified with HC1 and extracted with 3x150 mL... 

There have been reported numerous advantages of SFE for the extraction of natural products including reduction of extraction cost and time, environmental acceptance, and lack of toxicity to human health compared with conventional organic solvent extraction. However, the high polarity of alkaloids due to salt formation in plant tissue has made it difficult to extract them using SFE. In order to develop a universally acceptable SFE method for alkaloids present in plant materials, a basified modifier has been introduced to the SFE of selected alkaloids. On the basis of these results, it is believed that SFE using basified modifiers can be used as an alternative to conventional solvent extraction for alkaloids from plant material. 

A solution of LAH (1.0 M in ether, 36.5 mL, 36.5 mmol) was cooled to 0 °C, and a solution of the cyanoethyl indole (2.78 g, 16.3 mmol) was added slowly. Then, the solution was heated at reflux for 3 h. It was cooled to 0 °C and quenched by dropwise addition of water (20 mL) followed by 1 N sodium hydroxide (40 mL). The phases were separated, and the aqueous phase was extracted with ether. The combined organic phases were washed with brine and then dried (potassium hydroxide). Evaporation of the solvent gave 2.6 g (92%) of homotryptamine as a yellow oil, which solidified on standing. The hydrochloride was prepared by dissolving the amine in a minimum of ethanol and then a saturated solution of hydrogen chloride in ether was added until no additional salt formation was observed. The hydrochloride was recrystallized from ethanol. 

This is defined as a reaction which effects a structural change and gives an isolable product, but which may or may not be isolated in practice. (This includes salt formations where isolated, but not transient formations in acid/base extractions). When making route comparisons, a higher number of steps would imply that more complex chemistry is being used to reach the target. 

The processes described above utilize the preference of ABC extractants for acids over their salts. These extractants, however, extract salts from acid-free solutions. Unlike the case of conventional metal ion extractants, both the cation and the anion of the metal salt are extracted, obviating the need for pH adjustment during extraction. As a result, no acid or base is required for stripping of the loaded extractant and the formation of by-product salts is avoided. The reversibility of the extractant provides for back-extraction of the extracted salt with water. 

Beneperidol has a pK of 7.90, and is a sufficiently weak base to be extracted by organic solvents from aqueous acid solution. It has been found in the present work that, due to the presence of the benzimidazolone ring system, beneperidol can also act as a weak acid when dissolved in strong alkali (pHll). Evidence of salt formation is seen in the bathochromic shift, from 279nm to 288nm, which occurs in the ultraviolet absorption spectrum of beneperidol when its aqueous solution is made alkaline."... 

Another method of determination of DSS is based on formation of the dioctyl sulfosuccinate salt of methylene blue, extraction of the salt into chloroform, and spectrophotometric determination of the extracted salt at 650 nm (30). 

The amino acids, because of their inner salt formation, are nearly insoluble in nonpolar solvents. Those amino acids which contain a nonpolar side chain (isoleucine, leucine, methionine, phenylalanine, tryptophan, valine) and proline have, however, significant solubility in lower alcohols and in mixtures of water and alcohols. Furthermore, if an aqueous solution of amino acids is subjected to continuous extraction with an organic solvent small amounts of amino acids may be transferred to the organic phase. Some of the amino... 

Uses Copromoter for cobalt-contg. polyester-accelerator systems solvent for cellulose ethers extractant ingred. of solvent mixts. for cellulose esters synthesis of nifedipine (a cardiac drug) org. synthesis reagent for Dane salt formation intermediate for vitamins, feed additives, pharmaceuticals, pesticides component for flavors and fragrances solvent for fragrances in cosmetics prod, of azo dyes Manuf./Distrib. Aceto http //www.aceto.com,... 

For TIOA with hydrochloric acid the concentration-based equilibrium constant for salt formation" according to reaction (8.2-6) is 1.51 x 10 and the equilibrium constant for amine-hydrochloride salt dimerization" is 8.0 M Combination of these parameters and the ion-complex stability constants with experimental metal-distribution data allows determination of the equilibrium constants for reactions (8.2-5) or (8.2-7). This completes the description of the amine-metal extraction-phase equilibria. For cobalt(II) in acidic sodium chloride solutions the equilibrium constant" for reaction (8.2-7) with TIOA is 2.0 X 10 and that for coppeifll) is 370 The corresponding value for zinc" is 7.5 x 10 Af -In spile of these relative values, the order of selectivity of TIOA for extraction of the metals is Zn > Cu > Co because of the relative extent of chloride complex formation. For the same reason, zinc stripping is difficult in this system, and copper has a tendency to be reduced to cuprous, which also complexes and extracts extensively. 

---