Carbonates ammonium

NH2COONH4 + H2O (NH4)2C03 The carbamate is decomposed by acids and their salts. 

Formula (NH4)2C03 H2O MW 114.10 not available in pure form crystalline products consist of double salts of ammonium carbonate, ammonium bicarbonate, and ammonium carbamate. 

Applications of ammonium carbonate are similar to those of ammonium bicarbonate. It is used in baking powder in fire extinguishers as mordant in dyeing for washing and defatting wools in tanning in manufacture of rubber products as a smelling salt as a source of ammonia, and as an expectorant. 

Colorless or translucent bard crystalline mass or white cubic crystals or powder sharp taste odor of ammonia decomposes at 58°C slow decomposition at ambient temperatures readily dissolves in cold water decomposes in hot water insoluble in liquid ammonia, alcohol and carbon disulfide. 

Ammonium carbonate is obtained by passing carbon dioxide into aqueous ammonia solution in a column or tower. Ammonia, carbon dioxide and water vapor are distilled and the vapors condensed into a sobd crystaUine mass. It also may be prepared by subliming a mixture of ammonium sulfate and calcium carbonate. 

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Add 15 g. of finely powdered ammonium carbonate gradually to 50 ml. of glacial acetic acid contained in a 150 ml. round-bottomed flask, shaking the mixture during the addition to ensure a steady evolution of carbon dioxide. When all the carbonate has... 

Required Toluene-/)-sulphonyl chloride, 5 g. ammonium carbonate, 10 g. 

Ltease test. The enzyme uretwe hydrolyses urea to ammonium carbonate (p. 519). The reaction is sp ific and is frequently used for solu tions of urea to which the biuret test cannot be applied. Add about 5 drops of phenohred to o 2 g. of urea dissolved in 5 ml. of water. To this yellow solution, add 0 2 g. of jack bean meal suspended in 2 ml. of water containing. also 5 drops of phenol-red. The colour changes to red as the solution becomes alkaline. 

Urease soya bean, jack bean urea ammonium carbonate 7-2-7 9... 

The principle of this test is as follows The liquid suspected of containing urea is treated with dilute acid or alkali until its pH is about 7. A solution of the enzyme is also made and its pH adjusted to 7. The two solutions are mixed and the resulting conversion of urea to ammonium carbonate causes the pH of the solution to rise to over 8 this change is noted by the use of a suitable indicator, phenol-red being the one usually employed. Proteins do not interfere with the test, but the reaction is inhibited by traces of heavy metals. 

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 ... 

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... 

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. 

The mixture of o- and p-toluenesulplionyl chlorides produced from toluene may be separated by cooling to — 10° to — 20° when most of the p-isomer, which is a solid, m.p. 69°, separates out. Both isomers may be easily converted (e.g., by treatment with solid ammonium carbonate or with concentrated ammonia solution) into the corresponding highly crystalline siilphonamides which may be employed for Interesting syntheses. 

Dimethylpyrrole (II) is obtained by heating acetonylacetone (I) with ammonium carbonate at 100° ... 

In a 250 ml. conical flask, fitted with an air condenser of wide bore, place 50 g. (51 -5 ml.) of acetonylacetone (see Section V,9, Note 2) and 100 g. of ammonium carbonate (lump form). Heat the mixture in an oil bath at 100° until effervescence stops (60-90 minutes) some ammonium carbonate (or carbamate) sublimes into the condenser and this must be pushed back into the reaction mixture by means of a stout glass rod. Replace the air condenser by a Liebig s condenser with wide bore inner tube and reflux the mixture gently (bath temperature, 115°) for a further 30 minutes dissolve the solid which has sublimed into the condenser in about 5 ml. of hot water and return the solution to the reaction mixture. 

Hydantoins with one or two substituents in the 5-position may be obtained by heating cyanohydrins with ammonium carbonate or with urea. Thus ... 

Mix 42 5 g. of acetone cyanohydrin (Section 111,75) and 75 g. of freshly powdered ammonium carbonate in a small beaker, warm the mixture on a water bath FUME CUPBOARD) and stir with a thermometer. Gentle action commences at 50° and continues during about 3 hours at 70-80°. To complete the reaction, raise the temperature to 90° and maintain it at this point until the mixture is quiescent (ca. 30 minutes). The colourless (or pale yellow) residue solidifies on coohng. Dissolve it in 60 ml. of hot water, digest with a little decolourising carbon, and filter rapidly through a pre-heated Buchner funnel. Evaporate the filtrate on a hot plate until crystals appear on the surface of the liquid, and then cool in ice. Filter off the white crystals with suction, drain well, and then wash twice with 4 ml. portions of ether this crop of crystals of dimethylhydantoin is almost pure and melts at 176°. Concentrate the mother liquor to the crj staUisation point, cool in ice, and collect the... 

Ammonium Carbamate. Ammonium carbamate is a white crystalline soHd which is soluble ia water (2). It forms at room temperature by passiag ammonia gas over dry ice. In an aqueous solution at room temperature, it is slowly converted to ammonium carbonate, (NH2 2C02, by the... 

In the commonly used Welland process, calcium cyanamide, made from calcium carbonate, is converted to cyanamide by reaction with carbon dioxide and water. Dicyandiamide is fused with ammonium nitrate to form guanidine nitrate. Dehydration with 96% sulfuric acid gives nitroguanidine which is precipitated by dilution. In the aqueous fusion process, calcium cyanamide is fused with ammonium nitrate ia the presence of some water. The calcium nitrate produced is removed by precipitation with ammonium carbonate or carbon dioxide. The filtrate contains the guanidine nitrate that is recovered by vacuum evaporation and converted to nitroguanidine. Both operations can be mn on a continuous basis (see Cyanamides). In the Marquerol and Loriette process, nitroguanidine is obtained directly ia about 90% yield from dicyandiamide by reaction with sulfuric acid to form guanidine sulfate followed by direct nitration with nitric acid (169—172). 

Synthesis from Aldehydes and Ketones. Treatment of aldehydes and ketones with potassium cyanide and ammonium carbonate gives hydantoias ia a oae-pot procedure (Bucherer-Bergs reactioa) that proceeds through a complex mechanism (69). Some derivatives, like oximes, semicarbazones, thiosemicarbazones, and others, are also suitable startiag materials. The Bucherer-Bergs and Read hydantoia syntheses give epimeric products when appHed to cycloalkanones, which is of importance ia the stereoselective syathesis of amino acids (69,70). 

Lead Carbonate. Lead carbonate [598-63-0] PbCO, mol wt 267.22, d = 6.6g/cm, forms colorless orthorhombic crystals it decomposes at about 315°C. It is nearly insoluble in cold water (0.00011 g/100 mL at 20°C), but is transformed in hot water to the basic carbonate, 2PbC03 Pb(OH)2. Lead carbonate is soluble in acids and alkalies, but insoluble in alcohol and ammonia. It is prepared by passing CO2 iuto a cold dilute solution of lead acetate, or by shaking a suspension of a lead salt less soluble than the carbonate with ammonium carbonate at a low temperature to avoid formation of basic lead carbonate. 

Synthetic manganese carbonate is made from a water-soluble Mn (IT) salt, usually the sulfate, by precipitation with an alkafl or ammonium carbonate. The desired degree of product purity determines the quaUty of manganese sulfate and the form of carbonate to be used. For electronic-grade material, where the content of K O and Na20 cannot exceed 0.1% each, the MnSO is specially prepared from manganese metal, and ammonium bicarbonate is used (26) (see Electronic materials). After precipitation, the MnCO is filtered, washed free of excess carbonate, and then, to avoid undesirable oxidation by O2, dried carefljlly at a maximum temperature of 120°C. 

Metals can be precipitated from the Hquid or gas phase. For example, nickel ammonium carbonate gives nickel powder when subjected to hydrogen in an autoclave. Copper, cobalt, molybdenum, and titanium powders can also be formed by precipitation. 

Ammonium carbonate peroxohydrate, (NH 2 02 H2O2, first reported in 1980 (31), is crystalli2ed from a solution of ammonium hydrogen carbonate in aqueous hydrogen peroxide. The vibrational spectmm confirms the presence of molecular hydrogen peroxide. The compound is unstable and unlikely to find commercial appHcation. 

Raffinate acid from the first cycle, containing approximately 7 to 14 g/L U Og is then reoxidized and re-extracted in the second, purification cycle using a solvent containing 0.3 Af D2EHPA and 0.075 AfTOPO. The loaded solvent is washed with iron-free acid to remove iron and then with water to remove extracted and entrained acid. The solvent is stripped with ammonium carbonate [506-87-6] to yield ammonium uranyl tricarbonate [18077-77-5] which is subsequendy calcined to U Og (yellow cake). The stripped solvent is regenerated with mineral acid before recycling (39). 

Amino-2-hydroxybenzoic acid is manufactured by carboxylation of 3-amiaophenol under pressure with ammonium carbonate at 110 °C (182) or with potassium bicarbonate and carbon dioxide at 85—90°C (183) with subsequent acidification. 

Ammonia Hquor is fed to the top of the stiH and heated using steam vapor which dissociates the unstable ammonium salts, eg, ammonium carbonate and ammonium sulfite. 

Isolation of dry, normal ammonium acetate, prepared by neutralizing acetic acid with anhydrous ammonia or ammonium carbonate, is difficult because of ammonia loss during evaporation of water. Consequendy, commercial grades of ammonium acetate are often mixtures of the neutral and acid salts, or are suppHed as ammonium acetate solution [8013-61-4]. 

The earliest mention of an ammonium carbonate, salt of hartshorn, appears in English manuscripts of the 14th century. As the name implies, the material was obtained by dry distillation of animal waste such as horn, leather, and hooves. Although many salts have been described in the Hterature for the ternary NH —CO2—H2O system, most, except for ammonium bicarbonate [1066-33-7], NH HCO, ammonium carbonate [506-87-6], (NH 2 02, and ammonium carbamate [1111-78-0], NH4CO2NH2, are mixtures (5,6). 

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