Ammonium powder

Prior to the invention of smokeless powder various attempts had been made to improve blackpowder. In particular experiments were carried out to obtain sulphurless powder, ammonium powder (with ammonium nitrate instead of potas-... 

Ammonium powder (formerly termed amide powder) was obtained in attempts to increase the power of blackpowder. One of the causes of the relatively low power of blackpowder lies in the fact that on explosion it produces a great quantity of solid matter, but only a relatively small volume of gas. In working for an increase of the volume of the gaseous products in the middle of the nineteenth century, attempts were made to substitute ammonium nitrate for potassium nitrate. The observation of Reiset and Millon [29] that a mixture of ammonium nitrate and charcoal has explosive properties and explodes on being heated to 170°C was the starting point for this work. 

Ammonium powder obtained from ammonium nitrate and charcoal was also used successfully in guns of the Austrian navy between 1890-1896. It had however many disadvantages, since it was difficult to ignite, gave uneven results and was highly hygroscopic. This limited its use until it was withdrawn in all countries. 

It was not until World War I that, due to the shortage of cellulose and acids for nitration, an ammonium powder with a composition of ... 

Ammonium powder has the important disadvantage that ammonium nitrate occurs in various crystallographic forms with (Afferent specific gravities, one of the transitions taking place at + 32°C, i.e. only just above room or summer temperature (Vol. II). When a charge of ammonium powder is heated to this temperature a decrease in density occurs and in consequence there is an undesirable increase in rate of burning. 

During World War I 3000 tons of ammonium powder was produced monthly in Germany. 

A different type of ammonium powder containing ammonium bichromate was. also used to activate the Williams and James reciprocating engine. 

Another advance in this field was the use of ammonium nitrate as a chief component. In 1867 Ohlsson and Norrbin [3] patented a mining explosive—Ammoniak-krut (ammonium powder, cf. p. 331) consisting of ammonium nitrate mixed with 5-10% charcoal. Ohlsson and Norrbin added to this mixture 10-30% nitroglycerine to make detonation easier and to increase the power of the explosive. Similarly Nobel began to add ammonium nitrate to his dynamites. 

The mixture of ammonium nitrate and powdered aluminium is an explosive known as ammonal. 

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... 

Mix about 0 2 g. of each of the following powdered substances with about i g. of powdered soda-lime, preferably by grinding in a small clean mortar. The odour of ammonia in the cold usually indicates an ammonium ... 

Reflux a mixture of 1 g. of the ester, 3 ml. of benzylamine and 0 1 g. of powdered ammonium chloride for 1 hour in a Pyrex test-tube fltted with a short condenser. Wash the cold reaction mixture with water to remove the excess of benzylamine. If the product does not crystallise, stir it with a httle water containing a drop or two of dilute hydrochloric acid. If crystallisation does not result, some unchanged ester may be present ... 

The vanadium pentoxide catalyst Is prepared as follows Suspend 5 g. of pure ammonium vanadate in 50 ml. of water and add slowly 7 5 ml. of pure concentrated hydrochloric acid. Allow the reddish-brown, semi-colloidal precipitate to settle (preferably overnight), decant the supernatant solution, and wash the precipitate several times by decantation. Finally, suspend the precipitate in 76 ml. of water and allow it to stand for 3 days. This treatment renders the precipitate granular and easy to 6lter. Filter the precipitate with suction, wash it several times with cold 5 p>er cent, sodium chloride solution to remove hydrochloric acid. Dry the product at 120° for 12 hours, grind it in a mortar to a fine powder, and heat again at 120° for 12 hours. The yield of catalyst is about 3 - 5 g. 

Dissolve 0-5 g. of the substance in 10 ml. of 50 per cent, alcohol, add 0-5 g. of solid ammonium chloride and about 0 -5 g. of zinc powder. Heat the mixture to boiling, and allow the ensuing chemical reaction to proceed for 5 minutes. Filter from the excess of zinc powder, and teat the filtrate with Tollen s reagent Section 111,70, (i). An immediate black or grey precipitate or a silver mirror indicates the presence of a hydroxyl-amine formed by reduction of the nitro compound. Alternatively, the filtrate may be warmed with Fehling s solution, when cuprous oxide will be precipitated if a hydroxylamine is present. Make certain that the original compound does not aflfect the reagent used. 

Phenylhydroxylamine is formed when aniline is treated with a neutral reducing agent, e.g., zinc powder and aqueous ammonium chloride solution ... 

In a 2 litre bolt-head flask, equipped with an efficient mechanical stirrer, place 60-5 g. (50 ml.) of pure nitrobenzene and a solution of 30 g. of ammonium chloride in 1 litre of water. Stir vigorously and add 75 g. of a good quality zinc powder (about 90 per cent, purity) in small portions over a period of 5 minutes. The main reaction occurs about 5 minutes after the addition and the temperature rises. When the temperature reaches about 65°, add enough ice to the weU-stirred mixture to reduce the temperature to 50-55°. Filter the solution through a Buchner funnel twenty minutes after the first portion of zinc powder was introduced wash the zinc oxide residues with 600-700 ml. of boiling water. 

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... 

Molybdenum is also recovered as a by-product of copper and tungsten mining operations. The metal is prepared from the powder made by the hydrogen reduction of purified molybdic trioxide or ammonium molybdate. 

The metal is isolated commercially by a complex chemical process, the final stage of which is the hydrogen reduction of ammonium ruthenium chloride, which yields a powder. The powder is consolidated by powder metallurgy techniques or by argon-arc welding. 

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