AMMONIA A gas of the formula NH3, originally called alkaline air and volatile alkali and later in water solution called spirits of hartshorn. It isa by-product in the distillation of coal. It is also produced from naturalgas. Ammonia is readily absorbed by water, which at 60°F (16°C) takes up683 times its own volume of the gas, forming the liquid commonly calledammonia, but which is ammonium hydroxide, a colorless, strongly alkaline, and pungent liquid of the composition NH4OH with a boiling pointof 38°C. At 80°F (27°C) it contains 29.4% ammonia in stable solution. It isalso known as ammonium hydrate and aqua ammonia, and is used for thesaponifncation of fats and oils, as a deodorant, for cleaning and bleaching, for etching aluminum, and in chemical processing.
Ammonia gas is used in refrigeration, in nitriding steels, and in the manufacture of chemicals. Chlorine unites with it to form chloramines which are used as solvents, chlorinating agents, and disinfectants. The gas does not burn in the air, but a mixture of ammonia and oxygen explodes when ignited. Anhydrous ammonia is the purified gas liquefied under pressure,marketed in cylinders. At 20°C the liquid has a vapor pressure of 122.1lb/in2 (0.04 MPa). The anhydrous ammonia used for controlled atmo-
spheres for nitriding steel, bright annealing, and for sintering metals contains 90% NH3, and is oxygen-free. When dissociated by heat, each pound yields 45 ft3 (1.3 m3) of hydrogen and ll ft3 (0.31 m3) of nitrogen.
Smelling salts, sometimes referred to as ammonia, and in solution as aromatic spirits of ammonia, is ammonium carbonate, (NH4)2CO3·H20, forming in colorless or white crystals. It was also called hartshom salts.Ammonium bicarbonate, NH4HCO3, or acid ammonium carbonate, is a water-soluble white crystalline powder used as a source of pure ammonia and carbon dioxide and to decrease density in organic materials by creating voids such as for making foamed rubber and in the food-baking in-
dustry. It gasifies completely at 140°F (60°C). Ammonium gluconate, NH4C6H11O7, is a water-soluble white crystalline powder used as an emulsifier for cheese and mayonnaise and as a catalyst in textile printing.
Hydrazine, NH:NH, is a colorless liquid boiling at 113.5°C and freezing at 2°C. It is used as a propellant for rockets, yielding exhaust products of high temperature and low molecular weight. With a nickel catalyst it decomposes to nitrogen and hydrogen. It is a strong reducing agent, and is used in soldering fluxes. Reacted with citric acid, it produces the antituberculosis drug cotinazin, which is isonicotinic acid hydrazine. It is alsoused as a blowing agent for foamed rubber, and for the production of plastics. For industrial applications it may be used in the form of dihydrazine sulfate, (N2H4)2·H2SO4, a white crystalline water-soluble flake decomposing at 180°C and containing 37.5% available hydrazine. Hydrazine hydrate, N2H4· H20, is a colorless, water-miscible liquid boiling at 120.1°C, and freezing at - 51.7°C. Hydrazine is made by reacting chlorine and caustic soda and treating with ammonia.
The ammonium radical, NH4, has the chemical reaction of an alkali metal and forms many important chemicals. Ammonium nitrate is made by the action of nitric acid on ammonium hydroxide. It is a colorless to white crystalline hygroscopic powder of the composition NH4NO3, specific gravity 1.725, melting point 170°C, decomposing at 210°C, and soluble in water, alcohol, and alkalies. It is also used in fertilizers, pyrotechnics, dental gas, insecticides, freezing mixtures, and explosives. For use as a slowburning propellant for missiles it is mixed with a burning-rate catalyst in a synthetic-rubber binder and pressed into blocks. Riv, marketed by the Harrison Laboratories as a vapor-phase rust inhibitor, is ammonium nitrate. The British explosive is a mixture of ammonium nitrate and TNT, which explodes violently on detonation. The 50-50 mixture can be melted and poured, while the 80-20 mixture is like brown sugar and was used for filling large shells. Macite, for treetrunk blasting, is ammonium nitrate coated with TNT, with a catalyst to make it more sensitive. Akremite, of the Maumee Chemical Co., is ammonium nitrate and carbon black,used as an explosive in strip mining.
Ammonium perchlorate is another explosive made by the action of perchloric acid on ammonium hydroxide. It is a white crystalline substance of the composition NH4ClO4, specific gravity 1.95, is soluble in water, and decomposes on heating. Nitrogen trichloride, NCI3, which forms in reactions of chlorine and ammonia when there is an excess of chlorine, is a yellow oil of specific gravity 1.653, which is highly explosive. Ammonium sulfate, (NH4)2SO4, is a gray crystalline water-soluble material obtained in the distillation of coal and used as a fertilizer and for fireproofing.
Ammonium chloride, or sal ammoniac, NH4Cl, is a white crystalline powder of specific gravity 1.52, used in electric batteries, in textile printing, as a soldering flux, and in making other compounds. Many salts and metallic soaps are also formed in the same manner as with the alkali metals.Ammonium vanadate, NH4VO3, is a white to yellow crystalline powder used as a paint drier, in inks, as a mordant for textiles, and in pottery mixes to produce luster. The specific gravity is 2.326, and it decomposes at
210°C. Ammonium chromate, (NH4)2CrO4, is a bright-yellow water-solu-ble granular powder used as a textile mordant, in inks, and for the insolubilization of glues. On boiling, the water solution liberates ammonia. At 180°C the powder decomposes to the dichromate. Ammonium lactate,CH3CHOHCOONH4, is a yellowish syrupy liquid with a slight odor of ammonia, used in leather finishing. Ammonium stearate is obtainable as a tan-colored waxlike solid, melting at 74°F (23°C). It can be dispersed in hot water, but above 190°F (88°C) it decomposes to ammonia and stearic acid.
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