Blue sodium ammonia

If a solution containing approximately 4 mole percent sodium in ammonia is cooled below -42°C (231 K) a remarkable liquid-liquid phase separation occurs (33, 155). The solution physically separates into two distinct layers—a low-density, bronze metallic phase that floats out on top of a more dense, less concentrated dark-blue phase. The first experimental observation of this striking phenomenon in sodium-ammonia solutions was made by Kraus (109, 110) in 1907 more recent studies have mapped out the phase coexistence curves for a variety of alkali and alkaline earth metals in liquid ammonia, and these are delineated and discussed elsewhere (164). 

Sodium Benzenetellurolate1 This reaction must be carried out under nitrogen or argon in an apparatus suitable for work with liquid ammonia2. A filtered suspension of 0.35 g (15 mmol) of sodium in 25 ml of liquid ammonia is added to a suspension of 3.1 g (7.5 mmol) of diphenyl ditellurium in 15 ml of liquid ammonia. The blue color of the sodium/ammonia solution changes rapidly to yellow. The reaction is complete when the solid ditellurium compound has disappeared. The reaction mixture is then filtered, the ammonia is evaporated, and the grey residue is washed with petroleum ether yield 3.1 g (95%). 

Sodium (8.5 g, 0.37 mol) was added to dry liquid ammonia (250 mL) contained in a three-neck flask fitted with a dry-ice condenser. The mixture was stirred for 20 min and a solution of 7-chloro-l-iso-propoxybicyclo[4.1.0]heptane (10.5 g, 61 mmol) in EtjO (20 mL) was added dropwise over 35 min. The solution was stirred for 5 h and then treated with sufficient NH4CI to discharge its blue color. Ammonia was allowed to evaporate, and the residue was dissolved in a HjO/Et O mixture. The Et O extract was processed in the usual manner and fractionally distilled. Flash distillation of the residue in vacuo gave 2.8 g (33%) of the product. 

Aldehydes or ketones containing a cyclopropyl group adjacent to the carbonyl group can be converted to ring-opened carbonyl compounds by several different types of two-electron reduction processes. The most widely used method employs lithium metal in liquid ammonia as the reductant. The cyclopropyl ketone is usually dissolved in anhydrous diethyl ether and added to the blue metal-ammonia solution. Occasionally, the order of addition is reversed, and the lithium is added to a solution of the ketone in ammonia and diethyl ether. After a timed interval, the reduction is quenched by adding solid ammonium chloride to give a mixture of alcohols and ketones. This mixture is generally oxidized before isolation, with chromium(VI) oxide/pyridine or with sodium dichromate/sulfuric acid, to solely afford the ketone. 

CH3)2N]3P0. M.p. 4°C, b.p. 232"C, dielectric constant 30 at 25 C. Can be prepared from dimethylamine and phosphorus oxychloride. Used as an aprotic solvent, similar to liquid ammonia in solvent power but easier to handle. Solvent for organolithium compounds, Grignard reagents and the metals lithium, sodium and potassium (the latter metals give blue solutions). 

The alkali metals have the interesting property of dissolving in some non-aqueous solvents, notably liquid ammonia, to give clear coloured solutions which are excellent reducing agents and are often used as such in organic chemistry. Sodium (for example) forms an intensely blue solution in liquid ammonia and here the outer (3s) electron of each sodium atom is believed to become associated with the solvent ammonia in some way, i.e. the system is Na (solvent) + e" (sohem). 

This reaction also occurs slowly when sodium is dissolved in liquid ammonia initially a deep blue solution is formed which then decomposes giving hydrogen and sodium amide. 

Evidence for the solvated electron e (aq) can be obtained reaction of sodium vapour with ice in the complete absence of air at 273 K gives a blue colour (cf. the reaction of sodium with liquid ammonia, p. 126). Magnesium, zinc and iron react with steam at elevated temperatures to yield hydrogen, and a few metals, in the presence of air, form a surface layer of oxide or hydroxide, for example iron, lead and aluminium. These reactions are more fully considered under the respective metals. Water is not easily oxidised but fluorine and chlorine are both capable of liberating oxygen ... 

B) Preparation of the Cuprous Solution, Add 85 ml. of concentrated ammonia solution (d, o-o88) to a solution of 50 g. of crystalline copper sulphate in 200 ml. of water, and cool to 10 . Dissolve 14 5 g. of hydroxylamine hydrochloride (or 17-4 g. of the sulphate) in 50 ml. of water, cool to 10 , and add a solution of 9 g. of sodium hydroxide in 30 ml. of water. Without delay add this hydroxylamine solution with stirring to the copper solution, which will be immediately reduced, but will retain a blue colour. 

The special reducing agent (a solution containing cupro-ammonia ions) is first prepared. Dissolve 63 g. of crystallised copper sulphate in 250 ml. of water in a 1-Utre heaker, add 100 ml. of concentrated ammonium hydroxide solution (sp. gr. 0-88), and cool the solution to 10°. Dissolve 17 8 g. of hydroxylammonium chloride or 21 g. of hydroxylammonium sulphate in 60 ml. of water, cool to 10°, and add 42 -5 ml. of QN sodium hydroxide solution if the resulting solution of tydroxylamine is not clear, filter it at the pump. Without delay add the hydroxylamine solution, with stirring, to the ammoniacal cupric sulphate solution. Reduction occurs at once, a gas is evolved, and the solution assumes a pale blue colour. Protect the reducing agent from the air if it is not used immediately. 

Primary aromatic amides are crystaUine sohds with definite melting points. Upon boiling with 10-20 per cent, sodium or potassium hydroxide solution, they are hydrolysed with the evolution of ammonia (vapour turns red htmus paper blue and mercurous nitrate paper black) and the formation of the alkah metal salt of the acid ... 

Iron, cobalt, and nickel catalyze this reaction. The rate depends on temperature and sodium concentration. At —33.5°C, 0.251 kg sodium is soluble in 1 kg ammonia. Concentrated solutions of sodium in ammonia separate into two Hquid phases when cooled below the consolute temperature of —41.6°C. The compositions of the phases depend on the temperature. At the peak of the conjugate solutions curve, the composition is 4.15 atom % sodium. The density decreases with increasing concentration of sodium. Thus, in the two-phase region the dilute bottom phase, low in sodium concentration, has a deep-blue color the light top phase, high in sodium concentration, has a metallic bronze appearance (9—13). 

The mauve colored cobalt(II) carbonate [7542-09-8] of commerce is a basic material of indeterminate stoichiometry, (CoCO ) ( (0 )2) H20, that contains 45—47% cobalt. It is prepared by adding a hot solution of cobalt salts to a hot sodium carbonate or sodium bicarbonate solution. Precipitation from cold solutions gives a light blue unstable product. Dissolution of cobalt metal in ammonium carbonate solution followed by thermal decomposition of the solution gives a relatively dense carbonate. Basic cobalt carbonate is virtually insoluble in water, but dissolves in acids and ammonia solutions. It is used in the preparation of pigments and as a starting material in the preparation of cobalt compounds. 

Copper Hydroxide. Copper(II) hydroxide [20427-59-2] Cu(OH)2, produced by reaction of a copper salt solution and sodium hydroxide, is a blue, gelatinous, voluminous precipitate of limited stabiUty. The thermodynamically unstable copper hydroxide can be kiaetically stabilized by a suitable production method. Usually ammonia or phosphates ate iacorporated iato the hydroxide to produce a color-stable product. The ammonia processed copper hydroxide (16—19) is almost stoichiometric and copper content as high as 64% is not uncommon. The phosphate produced material (20,21) is lower ia copper (57—59%) and has a finer particle size and higher surface area than the ammonia processed hydroxide. Other methods of production generally rely on the formation of an iasoluble copper precursor prior to the formation of the hydroxide (22—26). 

In small portions, just sufficient to maintain the blue color, 5.0 g. (0.22 gram atom) of clean, metallic sodium is added with vigorous stirring. After dissolution is complete (Note 3), a solution of 23.4 g. (0.20 mole) of indole (Note 4) in 50 ml. of anhydrous ether is added slowly and then, after an additional 10 minutes, a solution of 31.2 g. (0.22 mole) of methyl iodide in an equal volume of anhydrous ether is added dropwise. Stirring is continued for a further 15 minutes. Fhe ammonia is allowed to evaporate (Note 5), 100 ml. of water is added, followed by 100... 

The general reaction procedure and apparatus used are exactly as described in Procedure 2. Ammonia (465 ml) is distilled into a 2-liter reaction flask and to this is added 165mlofisopropylalcoholandasolutionof30g(0.195 mole) of 17/ -estradiol 3-methyl ether (mp 118.5-120°) in 180 ml of tetrahydrofuran. The steroid is only partially soluble in the mixture. A 5 g portion of sodium (26 g, 1.13 g-atoms total) is added to the stirred mixture and the solid dissolves in the light blue solution within several min. As additional metal is added, the mixture becomes dark blue and a solid (matted needles) separates. Stirring is inefficient for a few minutes until the mass of crystals breaks down. All of the sodium is consumed after 1 hr and 120 ml of methanol is then added to the mixture with care. The product is isolated as in Procedure 4h 2. After being air-dried, the solid weighs 32.5 g (ca. 100% for a monohydrate). A sample of the material is dried for analysis and analyzed as described in Procedure 2 enol ether, 91% unreduced aromatics, 0.3%. The crude product may be crystallized from acetone-water or preferably from hexane. 

The reduction is carried out much as described in Procedure 2. Ammonia (950 ml) is distilled into a 5-liter reaction flask and 950 ml of /-amyl alcohol and a solution of the ketal in 950 ml of methylcyclohexane are added with good stirring. Sodium (57 g, 2.5 g-atoms) is added in portions. The reaction mixture becomes blue within 30-45 min after the sodium is added and the metal is consumed within about 3 hr after the blue color appears. After the mixture becomes colorless, 200 ml of ethanol is added and the ammonia is allowed to boil off through a mercury trap. Then 500 ml of water and 500 ml 0% potassium bicarbonate solution are added and the organic layer is separated. The organic layer is washed once with 10 % potassium bicarbonate... 

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