A- ammonium nitrate

In the U.S.A. ammonium nitrate is available commercially in different forms. There are prilled, flaked and granular forms. 

Ammonium nitrate (NH4N03), a colorless crystalline solid, occurs in two forms (1) a-ammonium nitrate (tetragonal crystals, stable between -16°C and 32°C melting point 169.9°C density 1.66) and (2) (3-ammonium nitrate (rhombic or monoclinic crystals, stable between 32°C and 84°C with decomposition occurring above 210°C density 1.725). 

Write formulas for each of the following compounds (a) ammonium nitrate, (b) mercury(I) cyanide, and (c) uranyl carbonate. 

Unknown Name txplosives. a) Ammonium Nitrate Explosive of Societe Suisse des Explosifs AN 70, PETN 10, TNT 10 NaNH HP0. 4H 0 10% [SwissP 228940 (1943) CA 42, 6538 (1938)] b)Plastic Explosives of O. Matter l)Mixt of coal tar distillates with inorganic oxidizers, such as nitrates, chlorates or perchlorates [SwissP 220755 (1942) CA 42, 6538(1948)] and 2)Mixt of a watei-insol hydrocarbon (such as chloronaphthalene) and resinous thickening agent (such as rosin or car dlstillation residue) with inorganic oxidizers (such as nitrates, chlorates or perchlorates) [SwissP 228653 (1943) CA 43,... 

It is prepared by the direct nitration of toluene with a mixture of nitric and sulphuric acids. TNT is a very stable, violent and powerful high explosive, but less sensitive to shock and friction than picric acid. It is widely used as a filling for shells, bombs, etc. often mixed with ammonium nitrate and other high explosives. The lower grades of TNT may contain isomers which under hot storage conditions may give rise to exudation. 

This can be prepared by the controlled reduction of a nitrite (nitrate(lll)) or nitrate. Cautious heating of ammonium nitrate gives dinitrogen oxide by an internal oxidation-reduction process ... 

Note, (i) Care should be taken to distinguish between a residue of carbon which may be very difficult to bum off completely, and a really non-volatile residue due to the presence of a metallic derivative. Thus for instance starch leaves a hard black residue of carbon which can best be burned away by moistening with a saturated solution of ammonium nitrate and then reheating. 

Method 2. Place 0-2 g. of cupric acetate, 10 g. of ammonium nitrate, 21 2 g. of benzoin and 70 ml. of an 80 per cent, by volume acetic acid -water solution in a 250 ml. flask fitted with a reflux condenser. Heat the mixture with occasional shaking (1). When solution occurs, a vigorous evolution of nitrogen is observed. Reflux for 90 minutes, cool the solution, seed the solution with a crystal of benzil (2), and allow to stand for 1 hour. Filter at the pump and keep the mother liquor (3) wash well with water and dry (preferably in an oven at 60°). The resulting benzil has m.p. 94-95° and the m.p. is unaffected by recrystallisation from alcohol or from carbon tetrachloride (2 ml. per gram). Dilution of the mother liquor with the aqueous washings gives a further 1 Og. of benzil (4). 

The urea produced is normally either prilled or granulated. In some countries there is a market for Hquid urea—ammonium nitrate solutions (32% N). In this case, a partial-recycle stripping process is the best and cheapest system. The unconverted NH coming from the stripped urea solution and the reactor off-gas is neutralized with nitric acid. The ammonium nitrate solution formed and the urea solution from the stripper bottom are mixed, resulting in a 32—35 wt % solution. This system drastically reduces investment costs as evaporation, finishing (priQ or granulation), and wastewater treatment are not required. 

Mixed with additives, urea is used in soHd fertilizers of various formulations, eg, urea—ammonium phosphate (UAP), urea—ammonium sulfate (UAS), and urea—phosphate (urea + phosphoric acid). Concentrated solutions of urea and ammonium nitrate (UAN) solutions (80—85 wt%) have a high nitrogen content but low crystallization point, suitable for easy transportation, pipeline distribution, and direct spray appHcation. 

The Bachmann process, used in the United States and in some European countries, is a simplification of a series of complex reactions. In this process, a solution of one part hexamine in 1.65 parts acetic acid, and a solution of 1.50 parts ammonium nitrate dissolved in 2.0 parts nitric acid and 5.20 parts acetic anhydride are used. The reaction may be summarized as ... 

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). 

Pure ammonium nitrate decomposes in a complex manner in a series of progressive reactions having different thermochemical effects (Table 17). Oxygen is Hberated from combination with combustibles only at temperatures above 300°C. When a combustible material such as fuel oil is present in stoichiometric proportions (ca 5.6%) the energy evolved increases almost threefold... 

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