Concentrated ammonia solution

Ammonia solution (concentrated, 0.880 , about 35 per cent NH3). Preferably the special atomic absorption spectroscopy reagent grade should be used. 

Ammonia solution (concentrated). The commercial concentrated ammonia solution is a water-like liquid with a characteristic smell, owing to the evaporation of ammonia gas. It has a density of 090 gem-3, contains 58-6% (w/w) NH3 (or 0-53 g NH3 per ml), and is approximately 15 1 molar. It should be handled with care, wearing eye protection. Direct smelling of the solution should be avoided. The solution should be kept far apart from concentrated hydrochloric acid to avoid the formation of ammonium chloride fumes. 

BP Ammonia solution, concentrated PhEur Ammoniae solution concentrata USPNF Strong ammonia solution... 

Ammonia solution (concentrated). The commercial concentrated ammonia solution is a water-like liquid with a characteristic smell, owing to the evaporation of ammonia gas. It has a density of 0.90gcm contains 58.6% (w/w) NH3 (or... 

Ammonia solution, concentrated Prepare a ten-fold diluted solution of NH4OH (in the purest water available). 

Figure 1. Absorption spectrum in dilute sodium-ammonia solution (concentration 5 X 10" M) (Reference 25).

C. A typical aromatic amine. Best prepared by the prolonged action of concentrated ammonia solution at a high temperature upon anthraquinone-l-sulphonic acid in the presence of BaClj and by reduction of the corresponding nitro compound or by amination of the chloroanthraquinone. 

Prepared by stirring phthalimide with cold concentrated ammonia solution. Hydrolysed to phlhalic acid with dilute acids. Dehydration with ethanoic anhydride gives first n-cyano-benzamide and then phthalonitrile. 

Schweizer s reagent The dark blue solution obtained by dissolving Cu(OH)2 in concentrated ammonia solution. Used as a solvent for cellulose, the cellulose is precipitated on acidification. Used in the cuprammonium process for the manufacture of rayon. 

For this second reaction Kjgs = 181 x 10" and hence pK, for ammonia solution is 4.75. The entity NHj. H2O is often referred to as ammonium hydroxide, NH4OH, a formula which would imply that either nitrogen has a covalency of five, an impossible arrangement, or that NH4OH existed as the ions NH4 and OH". It is possible to crystallise two hydrates from concentrated ammonia solution but neither of these hydrates is ionic. Hence use of the term ammonium hydroxide is to be discouraged in favour of ammonia solution . 

When cobalt(II) chloride was dissolved in water, a pink solution A was formed. The addition of concentrated hydrochloric acid to A gave a blue solution B. If solution A was treated with concentrated ammonia solution a blue-green precipitate was formed upon addition of further ammonia solution followed by the passage of air through the mixture, an orange-red solution C was produced. 

Oxamide differs from most aliphatic acid amides in being almost insoluble in water, and therefore can be readily prepared from the diethyl ester by Method 2(a). Place a mixture of 5 ml. of concentrated [d o-88o) ammonia solution and 5 ml. of water in a 25 ml. conical flask, for which a welTfitting cork is available. (The large excess of... 

Succinamide. NHoCOCH2 CH2CONH2. (Method 2(a)). Add 5 ml. (5 8 g.) of dimethyl succinate to a mixture of 50 ml. of water and 25 ml. of concentrated [dy o-88o) aqueous ammonia solution in a 150 ml. conical flask. Cork the flask and shake the contents the dimethyl succinate rapidly dissolves to give a clear solution. Allow the solution to stand after about i hour the succinamide starts to crystallise, and then continues to separate for some time. Next day, filter off the succinamide at the pump, wash with cold water, and drain. Recrystallise from water, from which the succinamide separates as colourless crystals the latter soften at 240° and melt at 254 -255° with... 

Add 15 g, of chloroacetic acid to 300 ml. of aqueous ammonia solution d, o-88o) contained in a 750 ml. conical flask. (The manipulation of the concentrated ammonia should preferably be carried out in a fume-cupboard, and great care taken to avoid ammonia fumes.) Cork the flask loosely and set aside overnight at room temperature. Now concentrate the solution to about 30 ml. by distillation under reduced pressure. For this purpose, place the solution in a suitable distilling-flask with some fragments of unglazed porcelain, fit a capillary tube to the neck of the flask, and connect the flask through a water-condenser and receiver to a water-pump then heat the flask carefully on a water-bath. Make the concentrated solution up to 40 ml. by the addition of water, filter, and then add 250 ml. of methanol. Cool the solution in ice-water, stir well, and set aside for ca. I hour, when the precipitation of the glycine will be complete. 

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. 

Experiments involving the use of dimethyl sulphate should be carried out by students only under immediate supervision. Not only is the vapour of dimethyl sulphate highly poisonousy but the cold liquid itself is absorbed easily through the skin, with toxic results individual susceptibility to ditnethyl sulphate poisoning varies and may be very high. If the sulphate is splashed on to the hands, wash immediately with plenty of concentrated ammonia solution in order to hydrolyse the methyl sulphate before it can be absorbed through the skin (see p. 528). 

Place 5 ml. of benzaldehyde in a wide-necked stout-walled bottle of about 100 ml. capacity (a conical flask is too fragile for this purpose) and add 50 ml. of concentrated dy 0 880) ammonia solution. Cork the bottle securely, shake vigorously, and then allow to stand for 24 hours, by which time the layer of benzaldehyde at the bottom of the bottle will have been converted into a hard mass of hydrobenzamide. (If after 24 hours the crude hydrobenzamide is still syrupy, shake the mixture vigorously and allow to stand for another hour, when the conversion will be complete.) Break up the solid pellet with a strong spatula, filter at the pump, wash with water and drain thoroughly. Recrystallise from ethanol methylated spirit should not be used, as it contains sufficient water to cause partial hydrolysis back to benzaldehyde and ammonia. Hydrobenzamide is obtained as colourless crystals, m.p. 101° (and not 110° as frequently quoted) yield, 4 g. 

Ammonia. Small quantities of ammonia may be prepared with the aid of the apparatus depicted in Fig. II, 48,4. Concentrated ammonia solution (sp. gr. 0-88) is gently heated in the flask surmounted by an efficient reflux condenser. The gas is dried by passage through the tower which is loosely packed with soda lime or quicklime, and is then passed... 

Dissolve 3 g. of copper sulphate pentahydrate and 1 g. of sodium chloride in 12 ml. of hot water, and add a solution of 1 g. of sodium bisulphite in 10 ml. of 5 per cent, sodium hydroxide solution. Shake, cool under the tap, and wash the precipitated wlute cuprous chloride with water by decantation. Dissolve the cuprous chloride in a few ml. of concentrated ammonia solution and dilute with water to 10 ml. 

Upon heating the polymers, anhydrous gaseous formaldehyde is produced (compare Section 111,17). By allowing a mixture of concentrated ammonia solution and formalin to evaporate, hexamethylenetetramine (also called hexamine, vrotropine) CjHjjNj is formed ... 

Mix 50 ml. of formalin, containing about 37 per cent, of formaldehyde, with 40 ml. of concentrated ammonia solution (sp. gr. 0- 88) in a 200 ml. round-bottomed flask. Insert a two-holed cork or rubber stopper carrying a capillary tube drawn out at the lower end (as for vacuum distillation) and reaching almost to the bottom of the flask, and also a short outlet tube connected through a filter flask to a water pump. Evaporate the contents of the flask as far as possible on a water bath under reduced pressure. Add a further 40 ml. of concentrated ammonia solution and repeat the evaporation. Attach a reflux condenser to the flask, add sufficient absolute ethyl alcohol (about 100 ml.) in small portions to dissolve most of the residue, heat under reflux for a few minutes and filter the hot alcoholic extract, preferably through a hot water fuimel (all flames in the vicinity must be extinguished). When cold, filter the hexamine, wash it with a little absolute alcohol, and dry in the air. The yield is 10 g. Treat the filtrate with an equal volume of dry ether and cool in ice. A fiulher 2 g. of hexamine is obtained. 

Amides. TVeat the acid chloride cautiously with about 20 parts of concentrated ammonia solution (sp. gr. 0 - 88) and warm for a few moments. If no solid separates on cooling, evaporate to dryness on a water bath. Recrystallise the crude amide from water or dilute alcohol. 

Of the common esters, methyl oxalate (solid, m.p. 54°) and ethyl oxalate (liquid) give amides almost immediately upon shaking with concentrated ammonia solution. The resulting oxamide, m.p. 417°, is valueless as a derivative. The esters may, however, be easily hydrolysed and identified as above. 

By the action of concentrate aqueous ammonia solution upon esters. This process is spoken of as ammonolysls of the ester, by analogy with hydrolysis applied to a similar reaction with water. If the amide is soluble in water, e.g., acetamide, it may be isolated by distillation, for example ... 

Succinamide. Add 5 g. (4-8 ml.) of dimethyl succinate to 25 ml. of concentrated ammonia solution (sp. gr. 0-88) in a 100 ml. conical flask. Cork the flask and shake the contents for a few minutes aUow to stand for 24 hours with occasional shaking. Filter off the crystals of succinamide, and wash with a Uttle cold water. RecrystaUise from a little hot water. Dry in the steam oven and determine the m.p. The yield is 3-5 g. Pure succinamide melts at 254° with decomposition. 

Place 125 ml. of concentrated ammonia solution (sp. gr. 0-88) in a 600 ml. beaker and surround the latter with crushed ice. Stir the ammonia solution mechanically, and introduce the n-caproyl chloride slowly by means of a suitably supported separatory funnel with bent stem. The rate of addition must be adjusted so that no white fumes are lost. The amide separates immediately. Allow to stand in the ice water for 15 minutes after all the acid chloride has been introduced. Filter oflF the amide at the pump use the flltrate to assist the transfer of any amide remaining in the beaker to the Alter (2). Spread the amide on sheets of Alter or drying paper to dry in the air. The crude n-capro-amide (30 g.) has m.p. 98-99° and is sufficiently pure for conversion into the nitrile (Section 111,112) (3). Recrystallise a small quantity of the amide by dissolving it in the minimum volume of hot water and allowing the solution to cool dry on filter paper in the air. Pure n-caproamide has m.p. 100°. 

To 5 ml. of water add 1-2 drops of the secondary amine if it does not dissolve, add a drop or two of concentrated hydrochloric acid. Place 1 ml. of the reagent in a test-tube, add 0 -5-1 ml. of concentrated ammonia solution, followed by 0-5-1 ml. of the above amine solution, A precipitate indicates a secondary amine. A shght turbidity points to the presence of a secondary amine as an impurity. 

Amino acids may be prepared by the action of a large excess of concentrated ammonia solution upon a-chloro- or a-bromo-acids the presence of a considerable amount of ammonium carbonate often increases the yield of monoamino acid, for example ... 

Two compounds, which may be prepared from ethyl cyanoacetate and also find application in synthetical work, may be included here. Cyanoacetamide, prepar from ethyl cyanoacetate and concentrated ammonia solution ... 

Dissolve 180 g. of commercial ammonium carbonate in 150 ml. of warm water (40-50°) in a 700 ml. flask. Cool to room temperature and add 200 ml. of concentrated ammonia solution (sp. gr. 0 88). Introduce slowly, with swirling of the contents of the flask, a solution of 50 g. of chloroacetic acid (Section 111,125) in 50 ml. of water [CAUTION do not allow chloroacetic acid to come into contact with the skin as unpleasant burns will result]. Close the flask with a solid rubber stopper and fix a thin copper wire to hold the stopper in place do not moisten the portion of the stopper in contact with the glass as this lubrication will cause the stopper to slide out of the flask. Allow the flask to stand for 24-48 hours at room temperature. Transfer the mixture to a distilling flask and distil in a closed apparatus until the volume is reduced to 100-110 ml. A convenient arrangement is to insert a drawn-out capillary tube into the flask, attach a Liebig s condenser, the lower end of which fits into a filter flask (compare Fig.//, 1) and connect the... 

Place 425 ml. of concentrated ammonia solution (sp. gr. 0-88) in a 500 ml. round-bottomed flask and add slowly 75 g. of a-bromocaproic acid (Section 111,126). Stopper the flask tightly and allow it to stand in a warm place (50-55°) for 30 hours. Filter the amino acid at the pump and keep the filtrate A) separately. Wash the amino acid (ca. 26 g.) well with methyl alcohol to remove the ammonium bromide present. Evaporate the aqueous filtrate (A) almost to dryness on a steam bath. 

Gyanoacetamide. Place 150 ml. of concentrated aqueous ammonia solution (sp. gr. 0-88) in a 500 ml. wide-mouthed conical flask and add 200 g. (188 ml.) of ethyl cyanoacetate. Shake the cloudy mixture some heat is evolved and it becomes clear in about 3 minutes. Stand the loosely stoppered flask in an ice-salt mixture for 1 hour, filter rapidly with suction, and ash the solid with two 25 ml. portions of ice-cold ethanol. Dry in the air the yield of pale yellow cyanoacetamide is 110 g. (1). Recrystallise from 190 ml. of 95 per cent, ethanol a colourless product, m.p. 119-120 , is deposited with practically no loss. 

Cellulose. This is insoluble in water, hot and cold. It dissolves in a solution of Schweitzer s reagent (precipitated cupric hydroxide is washed free from salts and then dissolved in concentrated ammonia solution), from which it is precipitated by the addition of dilute acids. Cellulose is not hydrolysed by dilute hydrochloric acid. 

Reaction with chlorosulphonic acid ( chlorosulphonyl-ation ). Sulphonamides. Many aryl hahdes, either alone or in chloroform solution, when treated with excess of chlorosulphonic acid afford the corresponding sulphonyl chlorides in good yield (compare Section IV.106) the latter may be readily converted into the aryl sulphonamides by reaction with concentrated ammonia solution or with sohd ammonium carbonate. 

Sulphonamides. Mix together 1 0 g. of the dry acid or 1 - 2 g. of the anhydrous salt with 2 5 g. of phosphorus pentachloride f and heat under a reflux condenser in an oil bath at 150° for 30 minutes. Cool the mixture, add 20 ml. of dry benzene, warm on a steam bath and stir the solid mass well to extract the sulphonyl chloride filter. Add the benzene solution slowly and with stirring to 10 ml. of concentrated ammonia solution. If the sulphonamide precipitates, separate it by filtration if no solid is obtained, evaporate the benzene on a steam bath. Wash the sulphonamide with a little cold water, and recrystallise from water, aqueous ethanol or ethanol to constant m.p. 

Heat a mixture of 15 g. of p-nitroacetanilide and 75 ml. of 70 per cent, sulphuric acid (1) under a reflux water condenser for 20-30 minutes or until a test sample remains clear upon dilution with 2-3 times its volume of water. The p-nitroaniline is now present in the hquid as the sulphate. Pour the clear hot solution into 500 ml. of cold water and precipitate the p-nitroanihne by adding excess of 10 per cent, sodium hydroxide solution or of concentrated ammonia solution. When cold (cool the mixture in ice water, if necessary), filter the yellow crystalline precipitate at the pump, wash it well with water, and drain thoroughly. Recrystallise it from a mixture of equal volumes of rectified (or methylated) spirit and water or from hot water. Filter, wash and dry. The yield of p-nitroanihne, m.p, 148°, is 11 g. 

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