Dicyandiamide Nitrate

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). 

Amino guanidine bicarbonate, Amm acetate, Amm phosphate, Amm sulfate, apatite, asbestos, Ba sulfate, boron nitride, cerium oxide, cryolite, dicyandiamide, dimethyl oxamide, dimethyl urea, d sodium phosphate, mercurous nitrate, methylene urea,... 

Jousselin [26] prepared nitroguanidine by the action of anhydrous nitric acid or sulphuric acid on guanidine nitrate. The preparation of this substance by the action of sulphuric acid has been developed as an industrial method for the production of nitroguanidine. The method described by Marqueyrol and Loriette [27] follows somewhat different principles. It consists in acting with anhydrous nitric acid on guanidine sulphate which, in turn, is obtained on treating dicyandiamide with sulphuric acid. 

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. 

The most widely fised method for manufacturing guanidine nitrate was described in detail by Davis [60]. Its basic principle is heating dicyandiamide with two equivalents of ammonium nitrate at 160°C. Originally the mixture was fused... 

On hydrolysis with dilute sulfuric acid it yields urea. On treatment with ammonium sulfide it prefers to react with the hydrogen sulfide part of the molecule to form thiourea, not with the ammonia part to form guanidine, and the reaction is the commercial source of many tons of thiourea for the rubber industry. On evaporation for crystals, the solution yields dicyandiamide which constitutes a convenient source for the preparation of guanidine nitrate. 

The guanidine sulfate, without removal from the mixture, is then nitrated to nitroguanidine.7 The process yields a nitroguanidine which is suitable for use in nitrocellulose powder, but it suffers from the disadvantages that the dicyandiamide, which corresponds after all to two molecules of cyanamide, yields in theory... 

Nitroguanidine is produced in variable amount, usually along with some of the a-compound, by the nitration of the mixture of guanidine sulfate and ammonium sulfate which results from the hydrolysis of dicyandiamide by sulfuric acid. Conditions have... 

Dicyandiamide, which is readily obtainable from calcium cyanamide and is a stable commercial product, may be converted into guanidine nitrate by the action of ammonium nitrate, either in concentrated aqueous solution under pressure12,13 or by a fusion reaction.13-16 The latter procedure gives a very pure product and is to be preferred for laboratory practice. Directions for its use are given under procedure A. 

Guanidine nitrate, 94, 96, 97 from calcium cyanamide, 97 from dicyandiamide, 96... 

A modern substitute for black powder is Pyrodex. It is safer to transport, store, and use, and is cleaner burning than conventional black powder. Pyrodex incorporates both charcoal and sulfur but in much smaller proportions than in black powder, and potassium nitrate in addition to other ingredients. Pyrodex also contains potassium perchlorate, sodium benzoate, and dicyandiamide.57... 

The fuels are, for example, 5-aminotetrazole, azodicarbonamide, -> Guanidine nitrate, -> Nitroguanidine, dicyandiamide, -> Triamino-guanidine nitrate and similar compounds, as well as salts of, for example, 5-nitrobarbituric acid, urea derivatives and also nitra-mines and similar compounds. The oxidisers are, for example, alkali or alkaline earth nitrates, -> Ammonium, alkali or alkaline earth perchlorates and metal oxides. 

Nitroguanidine (NQ) was first prepared by Jousselin in 1887 (Fig. 1.3). However, during WWI and WWII it only found limited use, for example in formulations with AN in grenades for mortars. In more recent days NQ has been used as a component in triple-base propellants together with NC and NG. One advantage of the triple-base propellants is that unlike double-base propellants the muzzle flash is reduced. The introduction of about 50 % of NQ to a propellant composition also results in a reduction of the combustion temperature and consequently reduced erosion and increased lifetime of the gun. NQ can be prepared from dicyandiamide and ammonium nitrate via guanidinium nitrate which is dehydrated with sulfuric acid under the formation of NQ ... 

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