Extraction aqueous solutions

This dibromide in 640 ml of methanol is refluxed 2 hr with 35 g of potassium hydroxide in 35 ml of water. At the end of this period the methanol is removed in vacuo, replaced with water and the aqueous solution extracted... 

On evaporating the alcoholic solution under reduced pressure from a water bath held at 50-60° (Note 6) the residue weighs about 540 g. A mixture of 600 cc. of absolute alcohol and 10 cc. of concentrated sulfuric acid (Note 7) is then added. The mixture is then heated on the water bath under a reflux condenser for three hours. The excess of alcohol and some of the water formed are removed by distillation under reduced pressure and the residue again heated for two hours with 300 cc. of absolute alcohol and an additional 4 cc. of concentrated sulfuric acid. The alcohol is removed by distillation under reduced pressure, and when the ester has cooled to room temperature, the sulfuric acid is neutralized with a concentrated solution of sodium carbonate the ester (upper layer) is separated, and the aqueous solution extracted with ether, or preferably benzene about one-tenth of the yield is in the extract. The combined products are placed in a i-l. distilling flask and distilled under reduced pressure after the solvent and alcohol and water have been removed. The ester is collected at 94-990, chiefly at 97-98°/x6 mm. (Note 8). The yield of a product analyzing about 97-98 per cent ethyl cyanoacetate amounts to 474-492 g. (77-80 per cent of the theoretical amount) (Note 9). 

Collection of Nonsaponifiable Lipids. Two hundred ants from the 2-C14-acetate feeding were ground with sand and the resulting brei refluxed for 4 hours in 25 ml. of ethanol, ethanol-diethyl ether (3 to 1), and diethyl ether (twice). The extracts were pooled, the solvents were evaporated, and the residue was saponified by refluxing for 1 hour with 20 ml. of methanolic potassium hydroxide (10% potassium hydroxide in 60% aqueous methanol). An equal quantity of water was added and the aqueous solution extracted three... 

Classical extraction is achieved by mixing the samples with an organic solvent (solid-liquid extraction) such as acetonitrile, methanol, or ethanol, used either in the pure form or as a mixture or aqueous solution." Extraction time can be reduced by sonicating the samples. ... 

Into a 300-mL separatory funnel transfer the residue prepared in Section 6.1.1, 6.1.2 or 6.1.3 with 100 mL of distilled water and add lOmL of saturated sodium chloride aqueous solution. Extract the mixture twice with 50 mL of n-hexane. Combine the... 

The quinoline can be recovered by neutralization of the aqueous solution, extraction of the quinoline into ether, and distillation of the dried (over barium oxide) ether extract. 

The solution is then cooled in an ice bath and acidified by 200 g. of concentrated sulfuric acid (sp. gr. 1.84) previously mixed with 300 g. of cracked ice. The solution is again cooled in an ice bath. The thick floating layer of cyclopropanecarboxylic acid and various polymers is separated and the cold aqueous solution extracted once with 1 1. of ether, using a stirrer instead of shaking (Note 5). The extract and crude acid are combined and dried over SO g. of Drierite, and the solvent is removed in a 500-ml. modified Claisen flask2 on a steam bath. The residue is then distilled under reduced pressure. The yield of acid boiling at 94-95°/26 mm. or 117—118°/75 mm. is 63.5-68 g. (74-79%) (Note 6). 

Brominated Monomer/Oligomer Mixtures from IV (V). The brominated sulfone monomer/oligomer mixtures were preparedby two different methods. Method A A mixture of pyridine (70mL), IV (11.5 mmol), dibromobenzene (26.96g, 115 mmol), anhydrous potassium carbonate (7.94g, 57.5 mmol) and cuprous iodide (0.13g, 0.7 mmol) was heated at reflux under nitrogen for 24h. After cooling to room temperature, the reaction mixture was acidified with IN HC1 and the aqueous solution extracted with ether. The organic phase was reduced in volume to a brown gum which was washed several times with hexane and then dried to give a 75-95% yield of the dibromo product. 

Addition of a drop of 5% tetraphenylarsonium (TPA) chloride aqueous solution Extraction of Tc-TPA into chloroform (1)... 

A sample of the methanolic oxidation product was treated directly with powdered sodium borohydride. Water was added, the solvent allowed to evaporate, and the aqueous solution extracted with carbon tetrachloride. Methyl vinyl carbinol was shown to be the major product, but about 10% impurities were present. Reduction by stirring overnight with 1.0 Af sodium sulfite followed by extraction with carbon tetrachloride produced a solution which analyzed as methyl vinyl carbinol with about 1% impurities. 

A solution of (MeS)jCH (1.5 equiv) in TfTF was stirred at —78 C. 1.7 M BuLi in hexane (1.5 cquiv) was added dropwise, which resulted in a white precipitate. A 1 M solution of cyclobutanone in THF (1 equiv) was added dropwise, and the homogeneous solution was stirred for an additonal 1.5 h. The reaction was quenched at — 78 "C with ethanolic HOAc (1.5 equiv) and the mixture allowed to warm to rt. The THF was removed in a rotary evaporator, sat. aq NaHCO, was added, and the aqueous solution extracted CH2C12 (3 x). The combined organic extracts were dried and concentrated, giving a residue which was chromatographed (silica gel, 30 g per 1 g of crude product) to afford the pure adduct 6. 

Perfluoro(l, 2,3,4,5,6,7.8-octahydronaphthalene) (7 10 g, 23.6 mmol) and activated zinc powder (6g, 91.7 mmol) were placed in solvent (60 mL either dioxane, MeCN or DMF) and stirred under the conditions given in the scheme. Then, the mixture was poured into ice water (50 mL) and acidified with dil HC1. The organic layer was separated and the aqueous solution extracted with Et20. All organic extracts were combined, dried and distilled to yield ... 

Tetrafluorobenzene-],3-dicarbonitrile (2 g, 10 mmol) and KF (0.87 g, 15 mmol) were dissolved in MeCN (10 mL). The solution was cooled to 0 C and PrSH (0.76 g, 10 mmol) added dropwise under stirring. The mixture was kept for 12 h at 0 C, then the MeCN distilled off, H,0 (50 mL) added and the aqueous solution extracted with CHC13 (3 x 50 mL). The organic phase was washed with aq NaHCO, and with H,0, dried (MgS04) and distilled. The crude product was purified by chromatography (silica gel, hexane/ EtOAc 3 1) yield 1.7g (66%) mp < 50 C. 

Selenocyanoacetone, CH3.CO.CH2.SeCN,2 occurs when potassium selenocyanate reacts with chloroacetone in alcohol solution, the solution being evaporated, the residue taken up in water and the aqueous solution extracted with ether. Evaporation away of the solvent gives an oil, which yields an oily hydrazone with phenylhydrazine. 

Triethyl phosphonoacetate (11.2 g, 0.05 mol) is added dropwise at 20 °C to a slurry of 50 per cent sodium hydride (2.4 g, 0.05 mol) in 100 ml of dry 1,2-dimethoxyethane. After the addition, the reaction mixture is stirred for 1 hour at room temperature until gas evolution has ceased. Cyclohexanone (4.9 g, 0.05 mol) is added dropwise at such a rate that the temperature is maintained below 30 °C. After the addition, the solution is stirred for 15 minutes at room temperature during which time a viscous semi-solid appears. The mixture is taken up in a large excess of water, and the aqueous solution extracted with ether. The ether layer, after being dried over magnesium sulphate and evaporated, gives a liquid residue, b.p. 88-90 °C/10mmHg, 5.8 g (70%), 1.4704. 

In a typical experiment the heat-killed ligation mixture is adjusted, by the addition of further Tris HC1, NaCl and MgCl2, to the correct ionic conditions and pH for EcoRI digestion, 10-30 units of jEcoRI added and the mixture incubated for 3h at 37°C. Excess EDTA (pH 8.0) is added and the mixture extracted with aqueous phenol. The aqueous phase is removed, the phenol layer washed once with water, and the combined aqueous solutions extracted five times with 1 ml ether to remove phenol. Residual ether is evaporated off in a stream of air. 

In another paper, Faugeras and Paris investigated the alkaloids in Genista acanthoclada DC. The plant material was stabilized in boiling methanol and completely extracted with the same solvent. After evaporation of the solvent, the residue was taken up in water and the aqueous solution extracted with diethyl ether after addition of hydrochloric acid. After adjustment of the pH to 10 the alkaloid bases were extracted with diethyl ether and the extract obtained used for the gas chromatographic analysis, which was performed with packed columns using SE-30 and SE-52 as stationary phases. The retention times of the alkaloids found are given in Table 7.2. 

By extraction is meant the process of removing from a mixture, usually an aqueous solution, one or more substances by shaking with a liquid in which the substances to be removed are soluble. Aniline, for example, is somewhat soluble in water when the solution is shaken with ether a large part of the aniline is removed from the water and passes into solution in the ether. As aniline can be recovered much more readily from an ethereal solution than from an aqueous solution, extraction, of such solutions is made use of in the preparation of the compound. The liquid used for extracting must be immiscible with the solution to be extracted. 

Benzyl-4-chloro-6,8-dimethyl-5,6,7,8-tetrahydropyrido[4,3-<7]pyrimidine (8 g, 28 mmol) and morpholine (13 g. 149 mmol) were heated at reflux for 22 h, then the unreacted morpholine was evaporated in vacuo, the residue taken up in H20, and the aqueous solution extracted with Et20 (3 x ) to give the product yield 5 g (53%) tnp 93-94cC (50% aq EtOH). 

To a stirred solution of the dithiolium salt (1.3 mmol) and l2 (0.84 g, 6.6 mmol) in MeCN (40 mL) was added dropwise 33 % aq NH3 (0.8 mL, 13 mmol) at 20 JC. After stirring for 1.5 h, the solulion was added to H20 (300 mL) and the resultant aqueous solution extracted with CII2C12 (3 x 50 mL). The organic layers were combined, dried (MgS04) and evaporated under reduced pressure to give the crude product which was chromatographed (silica gel, CH,Cl2/hexane 1 1). 

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