Ammonium bicarbonate, decomposition

Ammonium bicarbonate, sp gr 1.586, formula wt 79.06, is the only compound in the NH —CO2—H2O system that dissolves in water without decomposition. SolubiUty in 100 g of H2O ranges from 11.9 g at 0°C to 59.2 g/100 g of H2O at 60°C (8). The heat of formation from gaseous ammonia and carbon dioxide andUquid water is 126.5 kj/mol (30.2 kcal/mol). Ammonium bicarbonate is manufactured by passing carbon dioxide gas... 

Chemical blowing agents undergo decomposition at the vulcanisation temperature to form a gaseous species such as nitrogen or carbon dioxide, e.g., azo compounds, nitroso compounds, sulphonyl hydrazide compounds, ammonium carbonate, ammonium bicarbonate and sodium bicarbonate. 

Ammonium chloride is also formed by the action of hydrochloric acid on a soln. of ammonia or ammonium carbonate J. G. Qentele 5 made it by the double decomposition of ammonium bicarbonate and sodium, magnesium, calcium, and other chlorides H. J. E. Hennebutte and E. Mesnard, and A. Dubose and M. Heuzey, made it by the action of ammonium bicarbonate or sulphate on the double chloride of iron and calcium and it is made by the action of soln. of ammonium sulphate and sodium chloride when the soln. is cone, the crystals of sodium sulphate separate out and they are removed by suitable shovels the cone. soln. of ammonium chloride which remains is purified by crystallization. Ammonium chloride can also be obtained by sublimation from a dry intimate mixture of the same two salts. A. French made it by the joint action of air and steam on a mixture of salt, pyrites, and carbon or organic matter 2NaCl+4H20-j-S02+C-j-N2=2NH4Cl-i-Na2S04-i-C02. 

Examples of foaming agents are sodium bicarbonate, ammonium bicarbonate and nitroso compounds. Especially, when dinitroso-pentamethylenetetramine is used, foaming aids can be added that accelerate the decomposition and reduce the decomposition temperature. This is achieved, for example, with salicylic acid, or with urea. Various chlorine and bromine flame retardants can be used as halogen-based flame retardants, e.g., tetrabromobisphenol A de-rivates. 

Criteria for Choice of Salt. Gilliland has chosen to call these chemical compounds thermolytic salts. He defines them as materials which, upon increase in temperature, reduction in pressure, or both, decompose into gases, or into gases and insoluble solids. The idea behind this is to have an ion exchange material that can be recovered without having to boil away all of the solvent, water. Also implicit in this idea is the wish that the ion exchange material, after its decomposition, be easily separable from water. It is on this last factor that ammonium bicarbonate does not meet the desiderata. 

Urease (E.C.3.5.1.5) catalyzes the hydrolytic decomposition of urea into ammonium, bicarbonate, and hydroxide ions. It has a molecular weight of 483 kDa, and preparations with specific activities of 10,000 U/mg at 37 °C and pH 7.0 are commercially available. 

The other bicarbonate system of some importance is ammonium bicarbonate, which decomposes in the range of 40-60° C. This material is difficult to process owing to the low decomposition temperature and high rate of decomposition with liberation of strong ammonia odor in the extrusion or injection molding processes. However, ammonium bicarbonate can be... 

We are dealing here, therefore, with reciprocal salt-pairs, the behaviour of which has just been discussed in the preceding pages. Since the study of the reaction is rendered more difficult on account of the fact that ammonium bicarbonate in solution, when under atmospheric pressure, undergoes decomposition at temperatures above 15 , this temperature was the one chosen for the detailed investigation of the conditions of equilibrium. Since, further, it has been shown by Bodlander that the bicarbonates possess a definite solubility only when the pressure of carbon dioxide in the solution has a definite value, the measurements were carried out in solutions saturated with this gas. This, however, does not constitute another component, because we have made the restriction that the sum of the partial pressures of carbon dioxide and water vapour is equal to i atmosphere. The concentration of the carbon dioxide is, therefore, not independently variable (p. 7). 

Turning now to the practical application of the data so obtained, consider first what is the influence of concentration on the yield of soda. Since the reaction consists essentially in a double decomposition between sodium chloride and ammonium bicarbonate, then, after the deposition of the sodium bicarbonate, we obtain a solution containing sodium chloride, ammonium chloride, and sodium bicarbonate. In order to ascertain to what extent the sodium chloride has been converted into solid sodium bicarbonate, it is necessary to examine the composition of the solution which is obtained with definite amounts of sodium chloride and ammonium bicarbonate. 

BIS (AMMONIUM) CARBONATE (506-87-6) (NH4)2COj Slightly combustible solid (Fire Rating 1). Contact with sodium hypochlorite causes sudden, possibly violent, decomposition. Becomes unstable and decomposes on exposure to air or in heat with loss of ammoiua and carbon dioxide, converting to powdery-white ammonium bicarbonate. Inconpatible with acids, acid salts, alkaloids, aluminum, calomel, iron salts, sodium nitrate, nitrites, zinc. Attacks nickel, copper, and other alloys. 

To adjust the pore system during the preparation process, a pore former is sometimes added. These pore formers must be eliminated after the electrode preparation, for example, by their dissolution in water or by their decomposition into gaseous components such as sodium or ammonium bicarbonate. 

The decomposition of ammonium carbonate is considered to proceed via the stable ammonium bicarbonate intermediate [87]. 

The mechanism of this reaction was discussed by the authors (Scheme 4.40). Initially, aldehydes are formed by the PIDA mediated oxidative C-C bond cleavage of 1,2-diols, which are generated from the dihydroxylation of alkenes [142]. Upon the decomposition of ammonium bicarbonate, the aldehydes could be trapped by ammonia to give imines, which would be further oxidized to give nitriles. This reaction shows the efiftciency of the combination of metal-free oxidant and inexpensive nitrogenation agent for the synthesis of nitriles, which should be of great value in further studies. 

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. 

Ammonia may be obtained by decomposition of ammonium carbonate or bicarbonate. Such reactions, however, are not applied in commercial production. 

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