Sodium glycolate chromatography

Sodium chloride sodium glycolate sodium chloroacetate Ion chromatography ... 

A solution of cholest-4-en-3-one (139), 1 g, in diethylene glycol dimethyl ether (20 ml) is treated for 1 hr with a large excess of diborane at room temperature under nitrogen and then left for a further 40 min. Acetic anhydride (10 ml) is added and the solution refluxed for 1 hr. The mixture is concentrated to a small volume, diluted with water and extracted with ether. The extracts are washed with 10% sodium hydroxide solution, then with water and dried over sodium sulfate. Removal of the solvent leaves a brown oil (1.06 g) which is purified by chromatography on alumina (activity I). Hexane elutes the title compound (141), 0.68 g mp 76-77°. Successive crystallization from acetone-methanol yields material mp 78-79°, [a]p 66°. 

Cyclohexanone (0.52 g, 5.3 mmol) is added, under a nitrogen atmosphere, to a mixture of dry ethylene glycol (3 mb, 54 mmol) and dry methanol (20 mb). Tri-methylchlorosilane 14 (1.4 mb, 11 mmol) is added and the mixture stirred for 16 h at room temperature. The mixture is neutralized to pH 6 by addition of a 5% solution of sodium methoxide in methanol and the solvent is removed under reduced pressure. The residue is dissolved in 20 mb ether and filtered through 5 g silica gel, which is then washed with 2x10 mb ether. The combined ether eluates are evaporated and the crude residue submitted to flash chromatography on silica gel with ethyl acetate-hexane (1 10) to give 0.63 g (83%) cyclohexanoneethylene ketal 392 [28] (Scheme 5.87). 

Figure 4.20 Calibration curves for size-exclusion liquid chromatography. Column, TSK GEL G3000SW, 120 cm x 7.5 mm i.d. eluent, 0.2 m sodium phosphate buffer pH 6.8 flow rate, 1.0 ml min-1. Standards 1, protein-, 2, dextran, and 3, polyethylene glycol.

The monophenol fraction was extracted with 10% sodium hydroxide to separate it into phenolics and neutral oils. The neutral oils were found to be about 20% of the monophenols fraction. After removing the neutral oils, individual phenols were identified by gas chromatography using the retention times on three separate columns, (1) 25% Celanese ester 9 on Chromosorb W, (2) 25% diethylene glycol succinate on Chromosorb W, and (3) 20% silicone SE-30 on Chromosorb W. Quantitative estimates were made using the celanese ester column. 

Gas chromatography has found some applications in the determination of simple aromatics in water. Mel kanovitskaya [31] has described a method for determining C6-C8 aromatics in subterranean waters. In this method the sample (25-50mL) is adjusted to pH8-9 and extracted for 3min with 0.5 or l.OmL of nitrobenzene the extract is washed with 0.3mL of 5% hydrochloric acid or 5% sodium hydroxide solution and with 0.3mL of water adjusted to pH7. The purified extract is subjected to gas chromatography at 85°C on a column (lm><4mm) packed with 15% of polyoxyethylene glycol 2000 on Celite 545 (60-80 mesh) and operated with nitrogen (lOmL min ) as carrier gas, decane as internal standard and flame ionisation detection. 

To a solution of 6.2 g (0.05 mol) of methyl phenyl sulfide in 50 mL of 95% ethanol is added 54.8 (0.1 mol) of the supported oxidant in one portion at room temperature. The mixture is stirred vigorously until the sulfide has been completely consumed, as detected by gas-liquid chromatography with a 5% Carbowax 20 M (a polyethylene glycol compound) column (5 h). After filtration of the solid and removal of most of the ethanol by evaporation of the filtrate, 25 mL of dichloro-methane is added. The solution is dried with anhydrous sodium sulfate and evaporated to dryness to give 5.54 g (88%) of methyl phenyl sulfoxide, bp 98-102 °C at 1 mm of Hg. 

Under an inert atmosphere, prepare a suspension of sodium hydride (0.96 g, 20 mmol [50 per cent in mineral oil]) in dry THF (50 mL) in a 250 mL twonecked round-bottomed flask fitted with a reflux condenser and pressure equalized addition funnel. Stir for 30 min under an inert atmosphere. Slowly add a solution of 8-hydroxyquinoline (2.90 g, 20 mmol) in dry THF (50 mL) to this through the addition funnel. Make up a solution of triethylene glycol ditosylate, 2, (4.60 g, 10 mmol) in dry THF (50 mL), ensuring that no solids remain (filter if necessary) or the addition funnel may become blocked. Once the effervescence subsides following the formation of the sodium 8-hydroxyquinolinate salt, add the ditosylate solution and reflux for 24 h. After 24 h, allow the solution to cool to room temperature, filter off the precipitated sodium tosylate and remove the THF by rotary evaporation. Dissolve the residue in dichloromethane (30 mL) and wash with distilled water (3 x 30 mL). Dry the organic phase over anhydrous sodium sulphate, filter and remove dichloromethane by rotary evaporation to give the crude product, l,9-bis(8-quinolinyloxy)-3,6-dioxanonane (4) as a pale brown oil. Further purification may be afforded by column chromatography (silica, elute with acetone/dichloromethane). 

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