Ammonium nitrate melting point

Blasting agents are powerful explosive agents that cannot be detonated by means of a blasting cap when unconfined and are, therefore, very safe to handle. A powerful booster is needed to start detonation. Blasting agents are usually ammonium nitrate (melting point 169.6°C, density 1.725) mixtures sensitized with nonexplosive fuels such as oil or wax. 

Ammonium nitrate (melting point 169.6 °C) exhibits five polymorphs and four enantiotropic changes between —18 and 125 °C, as shown below ... 

Ammonium nitrate decomposes into nitrous oxide and water. In the solid phase, decomposition begins at about I50°C (302°F) but becomes extensive only above the melting point (I70°C) (338°F). The reaction is first-order, with activation energy about 40 kcal/g mol (72,000 Btii/lb mol). Traces of moisture and Cr lower the decomposition temperature thoroughly dried material has been kept at 300°C (572°F). All oxides of nitrogen, as well as oxygen and nitrogen, have been detected in decompositions of nitrates. 

Cobalt reacts violently or even explosively with ammonium nitrate at a temperature close to its melting point ( 200°C). 

Interest has focused on derivatives of mannitol hexanitrate (14) as potential explosives because although this nitrate ester is a powerful explosive it has some property characteristics of a primary explosive. Treatment of mannitol hexanitrate (14) with pyridine or ammonium carbonate " in aqueous acetone leads to a very selective denitration with the formation of mannitol-1,2,3,5,6-pentanitrate (77). Marans and co-workers synthesized the acetate (78), the propionate (79), and the phenylacetate (80) derivatives of mannitol-1,2,3,5,6-pentanitrate and all have significantly lower melting points than mannitol hexanitrate. The incorporation of such groups can also help to increase the solubility of an explosive in the melt of another explosive. 

Ammonium nitrate (AN NH4NO3) is a white, crystalline material, the crystal structure of which varies with temperature.melting point is 442 K and its heat of fusion is 71.4 kj kg . Though the mass fraction of oxygen of AN is 0.5996, it is highly hygroscopic and absorbs moisture from the atmosphere to form liquid AN acid. This limits its application in propellants and pyrolants. However, AN is widely used as an oxidizer of explosives such as slurry explosives and ANFO (ammonium nitrate fuel oil) explosives. 

Historically, the following four main steps must be mentioned the preparation of ethylammonium nitrate [C2H5NH3][N03] by Paul Walden in 1914 is recognized by many as the first IL. This compound has a melting point of 12°C but owing to its high reactivity has not really found a use [1]. This was the outcome of his studies of conductivity and electrical properties of salt solutions, especially nonaqueous solutions of organic salts. He conducted very systematic studies with different solvents and salts, and his special interest was in ammonium salts. But Walden himself pointed on the work... 

The y -form is produced either alone or together with some of the a-compound, by the nitration of the mixture of guanidine sulphate and ammonium sulphate which results from the action of sulphuric acid on dicyandiamide. The /Worm crystallizes from water in thin, elongated plates. It is converted into the a-compound by solution in sulphuric acid and precipitation with water. Both forms of nitroguanidine melt at the same temperature. Several authors quote different melting points 232, 246, 257°C. 

A different method for lowering the melting point of ammonium nitrate was suggested a few years before World War II. It consists of the addition of hydrated magnesium nitrate (i.e. containing water of crystallization) Mg(N03)2.6H20 to... 

Nitrotripenta has been prepared by the nitration of tripentaerythritol with 99% nitric acid at 0-10°C. Nitrotripenta is readily soluble in hot benzene and in acetone, soluble in alcohol and chloroform, insoluble in water. Because of its relatively low melting point, nitrotripenta can be melted and poured, and can therefore be used as a coating agent and sensitizer for ammonium nitrate. 

The increase in the rate of decomposition under the influence of added Cr203 and K2Cr207 is shown on Figs. 171 and 172 respectively.lt has been found that an increase of the rate occurred only at temperatures near to the melting point of the samples. Guiochon [17] also found that cobalt salts increase the rate of thermolysis of ammonium nitrate. Other mineral salts (of manganese, nickel and copper) have a similar but much weaker action. A large number of salts of other metals are without any noticeable action. 

Ammonium nitrate prepared from ammonia obtained by the dry distillation of coal should not be used as component of any explosive material because of the ammonium thiocyanate and pyridine present in it (the latter as nitrate). When the ammonia liquor from dry distillation of coal was the sole source af ammonia and ammonium nitrate, decomposition of mixtures containing ammonium nitrate with TNT (amatols), was brought about at the melting point TNT reacted with ammonium thiocyanate or with pyridine nitrate and evolved gaseous products. Minute traces of these impurities were sufficient to cause abundant gas evolution to develop during the fusion, pouring, and cooling of amatol. 

The anhydrous salt yields yellowish-white crystals of density2 7-3 at 15° C. and melting point 3 1042° C. The specific heat is 4 0-0728 and the molar heat 05-4. The index of refraction is 2 2-14. It is insoluble in water, aqueous ammonia and in solutions of ammonium salts,5 and only slightly soluble in aqueous alkali or brine.6 It is decomposed when heated with hydrogen chloride,7 forming lead and arsenic chlorides, and in hot nitric acid it dissolves to form arsenic acid and lead nitrate, the latter being precipitated if the acid is sufficiently concentrated.8... 

The melting point generally ascribed to the alpha form is 169.6°C, with decomposition occurring above 210°C. Upon heating, ammonium nitrate yields nitrous oxide (N20) gas and can be used as ail industrial source of that gas. Ammonium nitrate is soluble in H2O, slightly soluble in ethyl alcohol, moderately soluble in methyl alcohol, and soluble in acetic acid solutions containing NH3. 

To a solution of 22.7 g of quinone monoguanylhydrazone nitrate in 250 ml water is added dropwise hot aqueous solution of 9.1 g thiosemicarbazide, then is added slowly a solution of 5 ml concentrated nitric acid in 10 ml of water. The mixture is stirred at 60°C for 1 hour. The product is dissolved in 1-1.2 L of water at 100°C. The solution is filtered and added to an aqueous ammonium solution. Blue residue of p-benzoquinone amidinohydrazone thiosemicarbazone is filtered and dried, melting point 188°C (decomp.). 

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). 

It forms an eutectic mixture (melting point 100 °C =212°F) when mixed with an equal amount of ammonium nitrate. 

Properties Yellow crystals. M. P. 182°. Not very powerful when used alone. Addition of TNT, picric acid, or other nitro high explosives serves the purpose of lowering the melting point os well as that of reinforcement. Mixtures of TNX and ammonium nitrate can be loaded by compression. 

TNT is a white, slightly yellow, or yellowish crystalline solid with a melting point of 80 Celsius. It is insoluble in water, but soluble in acetone, and benzene. It is widely used in the explosives field either by itself, or alloyed with other explosives such as RDX, HMX, or almost any meltable explosive. TNT is also commonly used when mixed with ammonium nitrate for use in military dynamites. TNT is one of the highest volume produced high explosive in the world, and during WWII, so much TNT was made that its preparation was ranked higher by volume then aspirin (180,000+ tones per year). TNT is widely used in... 

ETN forms colorless or white crystals, leaflets, or powder with a melting point of 61 Celsius. It is soluble in alcohol, ether, and glycerol, but insoluble in water. ETN explodes on strong percussion, but still requires a primary explosive for proper initiation when used in explosives compositions. ETN is used as a substitute for PETN in blasting cords, for use in explosives compositions, and nitroglycerine free dynamites when mixed with TNT, nitrocellulose, or ammonium nitrate. ... 

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