Saturated aqueous solution of sodium

Detection of Potassium in the presence of Sodium. Add a cold saturated aqueous solution of sodium picrate to a solution of potassium chloride. A rapid precipitation of the less soluble potassium picrate occurs, even from a i°o solution of potassium chloride. 

This sodium bisulphite reagent Is prepared by treating a saturated aqueous solution of sodium bisulphite with 70 per cent, of its volume (if rectified (or methylated) spirit, and then adding just sufiScient water to produce a clear solution. 

A. Ethyl mandelale. To 152 g. (1.0 mole) of mandelic acid and 200 ml. of absolute ethanol in a 1-1. round-bottomed flask f< ui[)ped with a reflux condenser, there is added 100 ml. of abso-liile ethanol containing about 10 g. of anhydrous hydrogen chlo-lidc (Note 1). The solution is heated under reflux on a steam bath for 5 hours, then poured into 11. of ice water in a 3-1. beaker (Note 2). A saturated aqueous solution of sodium bicarbonate is added until the mixture is faintly alkaline (Note 3). It is I lien extracted with two 300-ml. portions of ether in a 2-1. separatory funnel. The ether extracts are washed with a 200-ml. por-lioii of water and dried over 50 g. of anhydrous sodium sulfate. The dried ether solution is concentrated by distillation from a 25()-ml. Claisen flask, and the residue is distilled at reduced pressure. I here is obtained 147-154 g. (82-86%) of ethyl mandel-iilc, l).p. 144-145°/16 mm. The ester may crystallize upon standing for a prolonged period. It melts at 30.5-31.5°. 

Preparation of cholesta-5,7-diene-ia,3/3-diol a solution of 500 mg of the 1,4-cyclized adduct of cholesta-5,7-dien-3/3-ol-ia,2a-epoxideand 4-phenyl-1,2,4-triazoline-3,5-dione in 40 ml of tetrahydrofuran is added dropwise under agitation to a solution of 600 mg of lithium aluminum hydride in 30 ml of THF. Then, the reaction mixture liquid Is gently refluxed and boiled for 1 hour and cooled, and a saturated aqueous solution of sodium sulfate is added to the reaction mixture to decompose excessive lithium aluminum hydride. The organic solvent layer is separated and dried, and the solvent Is distilled. The residue Is purified by chromatography using a column packed with silica gel. Fractions eluted with ether-hexane (7 3 v/v) are collected, and recrystallization from the methanol gives 400 mg of cholesta-5,7-diene-la, 3/3-diol. 

Into a mixture of 1.6 g of 2-amino-4-methylpyrlmidine with 10 ml of glacial acetic acid is slowly added 2.13 g of concentrated sulfuric acid. A mixture of 2.4 g of 2-formyl-1-methyl-5-nitroimidazole in 20 ml of glacial acetic acid is slowly added to the mixture of the pyrimidine under stirring. The reaction mixture is maintained at a temperature of about 55°C for 4 hours. The resultant mixture is then diluted with 200 ml of distilled water and neutralized with a saturated aqueous solution of sodium bicarbonate. A brownish-yellow precipitate (MP 232° to 235°C) is formed and recovered. The product is analyzed by infrared spectroscopy and is found to conform to 2-amino-4-[2-(1-methyl-5-nitro-2-imidazolyI)vinyl] pyrimidine. 

Then 0.75 cc of freshly distilled ethyl formate is added. The air in the system is replaced with nitrogen and 150 mg of sodium hydride (as a 57% dispersion in mineral oil) is added. The mixture is stirred under nitrogen at room temperature for three hours. Then 15 cc of a saturated aqueous solution of sodium dihydrogen phosphate is added and the product is extracted into ether. 

The residue is dissolved in 300 ml. of water. The solution is poured onto 200 g. of ice and acidified to a pH of about 4 by addition of 75 ml. of 10% hydrochloric acid. The resulting mixture is extracted with four 100-ml. portions of peroxide-free ether, and the combined extracts are washed with 50 ml. of a saturated aqueous solution of sodium chloride and dried over 2 g. of anhydrous magnesium sulfate (Note 2). The ether solution is separated from the drying agent and concentrated at room temperature under reduced pressure. The residual oil is distilled from a 25-ml. 

Chlorine, hydrogen, caustic soda, and sometimes caustic potash are coproducts of the electrolysis of saturated aqueous solutions of sodium chloride called brine. The overall chemical reaction is given as... 

The reaction was hydrolysed and neutralized (pH = 8) in a 500 mL Erlenmeyer flask with a saturated aqueous solution of sodium bicarbonate. 

Incubate grids in a humid chamber on large drops of a saturated aqueous solution of sodium metaperiodate (prepared overnight, 1 g in 5 ml Aqua dest) for 30 60 min at room temperature. 

Saturated Sodium Sulphate Solution A saturated aqueous solution of sodium sulphate is prepared at 50 °C, cooled to room temperature and fdtered before use. 

After separation, the organic layer is washed with 300 mL each of saturated aqueous solutions of sodium carbonate and brine. Each aqueous layer Is extracted twice with 200 mL of ethyl acetate. The combined organic layers are dried over magnesium sulfate and the solvent is removed in a rotary evaporator at ca. 15 mm. Traces of solvent are removed by drying the residue at 60°C/0.05 mm for 2 hr under an oil pump vacuum to yield 19.8 - 20.5 g (0.100-0.104 mol, 93-95%) of the desired product. It is used directly in the next step (Note 14). 

Saturated aqueous solution of sodium mefa-periodate prepare daily. 

A. Ethyl 3-iodoproplonate. A 1-L, round-bottomed flask equipped with a magnetic stirring bar and a reflux condenser is charged with ethyl 3-chloropropionate (27.3 g, 0.2 mol) (Note 1) and acetone (400 mL). Sodium iodide (300 g, 2 mol) (Note 2) is added to the dear solution and the mixture is refluxed for 16 hr. The resulting pale yellow reaction mixture is cooled to room temperature, the stirring bar and reflux condenser are removed and the acetone is removed on a rotary evaporator at AO C/SSO mbar (412 mm). The residue is taken up in diethyl ether (300 mL) and washed with a saturated aqueous solution of sodium... 

Grayish-white metal hody-centered cubic crystalline structure density 19.3 g/cm3 melts at 3,422°C vaporizes at 5,555°C vapor pressure 1 torr at 3,990°C electrical resistivity 5.5 microhm-cm at 20°C modulus of elasticity about 50 to 57 x lO psi (single crystal) Poisson s ratio 0.17 magnetic sus-ceptibilty +59 x 10-6 thermal neutron absorption cross section 19.2 + 1.0 barns (2,200m/sec) velocity of sound, about 13,000 ft/sec insoluble in water practically insoluble in most acids and alkabes dissolves slowly in hot concentrated nitric acid dissolves in saturated aqueous solution of sodium chlorate and basic solution of potassium ferricyanide also solubibzed by fusion with sodium hydroxide or sodium carbonate in the presence of potassium nitrate followed by treatment with water... 

S. (E)-3-[(S -B-Phenyt-2 ppopenoxy]aarylio aoid. An oven dried, 1-L, three-necked, round-bottomed flask equipped with a mechanical stirrer, dropping funnel and reflux condenser is purged with argon and charged with 8.20 g (0.171 mol) of 50% sodium hydride in oil (Note 7) and 90 ml of anhydrous tetrahydrofuran (Note 8). To this mixture is added a solution of 19.0 g (0.143 mol) of cinnamyl alcohol (Note 9) in 180 ml of anhydrous tetrahydrofuran. The mixture is stirred for 30 min at which point 25.0 g (0.194 mol) of (E)-(carboxyvinyl)trimethylammonium betaine is added and the reaction mixture is heated at a gentle reflux for 15 hr. The cooled reaction mixture is slowly added to a mixture of 600 mL of water and 220 ml of a saturated aqueous solution of sodium chloride (Note 10). The residual... 

After washing with acetonitrile (1 mL, 6 times), the resins were washed with a saturated aqueous solution of sodium bicarbonate (200 pL), and then washed with water (more than 6 times) see Note 10). The Ninhydrin test is useful for estimation of the reaction ration. 

Sulphates. — Digest 5 gm. of lead peroxide with 30 cc. of a cold saturated aqueous solution of sodium bicarbonate for three or four hours, shaking frequently. Then filter, acidulate the filtrate with hydrochloric acid, boil the solution for ten minutes, and add 2 cc. of barium chloride solution. No precipitate of barium sulphate should form on standing twelve hours. 

Method. The derivatives are formed by shaking the sample (dissolved in acetone) for 1 h at 45 °C with a 3-5 molar excess of recrystallized DNS-C1. The reaction is buffered at pH 10.8.0.25 ml of 1N sodium hydroxide is then added in order to hydrolyze the unchanged DNS-C1. The derivatives are extracted with 3 ml of ethyl acetate after addition of 1 ml of a saturated aqueous solution of sodium chloride to the reaction mixture. The organic phase is used for TLC on activated layers of silica gel G. The cannabinoids yield mono-DNS derivatives with the exception of cannabidiol which forms a bis-DNS derivative. The following solvent systems are satisfactory for separation of cannabinoids on silica gel A, benzene-acetone (9 1) B, cyclohexane-ethyl acetate (5 1) C, cyclohexane-acetone-diethylamine (20 4 1) and D, cyclohexane-acetone-triethylamine (20 4 1). The R f values of nine cannabinoids in the above solvent systems are given in Table 4.25. 

Prepare 10 ml of saturated sodium metabisulphite solution and add 4 ml of the carbonyl compound shake thoroughly and observe the rise in temperature. Filter the crystalline precipitate at the pump, wash it with a little alcohol, followed by ether and allow it to dry. The sodium metabisulphite reagent is prepared by treating a saturated aqueous solution of sodium metabisulphite with 70 per cent of its volume of industrial spirit, and then adding just sufficient water to produce a clear solution. 

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