Guanidine nitrate

Guanidine nitrate exists as crystals melting at 215-216°C, soluble in water (4.64 g in 100 ml of water) and in alcohol. It may be recrystallized from the either of these solvents. 

Guanidine nitrate, being a rather weak explosive, can be detonated only with difficulty. 

Patart [58] determined experimentally that the force / of guanidine nitrate is 5834 m and hence he calculated the temperature of explosion t = 930°C. This low explosion temperature is probably a consequence of incomplete detonation due to the compound s poor aptitude to detonation. 

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 

A slightly different method of guanidine nitrate manufacture was introduced in German plants during World War II. It consists in the chemical combination of ammonium nitrate and cyanamide as defined by eqns. (12) and (13). 

Practically all methods which have been proposed for the preparation of guanidine salts involve either ammonation or ammonolysis of some derivative of carbonic acid. Phosgene,1 chloropicrin,2 and esters of orthocarbonic acid2 react with aqueous ammonia to give small yields of guanidine. The hydrochloride is obtained when carbon tetrachloride3 is acted upon by liquid ammonia under pressure. Urea4 is partially ammonolyzed in the presence of ammonium chloride. 

Fusion of ammonium thiocyanate,6,6 either alone or in the presence of heavy metal salts, at 180°C., gives guanidine thiocyanate. This procedure has been modified by heating lead nitrate with a solution of ammonium thiocyanate in liquid ammonia at 120°.7 Lead sulfide is formed, and guanidine nitrate recovered. Other methods of formation involve the hydrolysis of dicyandiamide8-10 and the nitridation11 of methyl amine by means of ammonium azide in liquid ammonia. 

Although methods involving the fusion of ammonium thiocyanate were for a long time the only ones employed 

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. 

Cyanamide is also acted upon directly by ammonium salts in aqueous and non-aqueous solutions.17-20 Since it is of decided advantage to avoid the isolation of pure cyanamide, methods have been developed in which aqueous solutions of cyanamide are prepared from calcium cyanamide and are then permitted to react with ammonium salts. However, guanidine nitrate may also be prepared directly from commercial calcium cyanamide by the action of ammonium nitrate. This reaction takes place readily in the fused state, in concentrated aqueous solution,21 or by direct admixture of solid ammonium nitrate with calcium cyanamide and subsequent heating to 100°C.22 The latter procedure is to be preferred, since better yields are obtainable and the hazard of fusion with ammonium nitrate is obviated. The directions given for procedure B require the use of a fairly good grade of unoiled calcium cyanamide containing approximately 65 per cent CaNCN. 

In a i-l. round-bottom flask is placed an intimate mixture of 210 g. of dicyanodiamidc (2.5 moles) and 440 g. of ammonium nitrate (5.5 moles) (Note 1). The flask is introduced into an oil bath at no-1200 and the temperature of the oil is raised during about half an hour to 160°. The bath is then held at this temperature (Note 2) for three hours. During the first hour the mass melts to a clear liquid which begins to deposit crystals and finally sets to a solid cake (Note 3). At the end of three hours the flask is removed from the bath the product is allowed to cool and is extracted on the steam bath with successive quantities of water (about 2 1. is necessary to bring all soluble material into solution) (Note 4). The solution is filtered to remove white amorphous insoluble material (ammelinc and ammelide) (Note 5). 

The filtrate contains guanidine nitrate along with a small amount of ammonium nitrate and very small amounts of dicyano-diamide and biguanide nitrate (Note 6). The solution is concentrated to about 1 1. and the guanidine nitrate which crystallizes on cooling is filtered off. A second crop is obtained by 

When the molten mass reaches 160 0 its temperature begins to rise above that of the bath, generally reaching 200° during the course of five or six minutes. The mass should not be stirred at any time, especially before the mixture has completely melted otherwise, the temperature may run somewhat higher. 

The guanidine nitrate begins to crystallize soon after the temperature of the mixture begins to fall. 

The hard cake goes into solution slowly and Lime must be given for each portion to become saturated before it is decanted. 

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It is conveniently prepared in the laboratory by the interaction of sulphanil-amide and guanidine (from guanidine nitrate and sodium methoxide solution) the resulting guanidine salt of sulphanilamlde decomposes upon heating at 150-160° into sulphaguanidine and ammonia ... 

In a 500 ml. three-necked flask, equipped with a thermometer, mechanical stirrer and efficient reflux condenser, dissolve 16 g. of sodium hydroxide pellets in 95 ml. of hot methyl alcohol. Add 49 g. of guanidine nitrate, stir the mixture at 50-65° for 15 minutes, and then cool to about 20°. Filter oflF the separated sodium nitrate and wash with two 12 ml. portions of methyl alcohol. Return the combined filtrates to the clean reaction flask, add 69 g. of sulphanilamide (Section IX,9) and stir at 50-55° for 15 minutes. Detach the reflux condenser and, with the aid of a still-head ( knee-tube ), arrange the apparatus for distillation from an oil bath with stirring about 100 ml. of methyl alcohol are recovered. Add 12 g. of pure cycZohexanol. Raise the temperature of the oil bath to 180-190° and continue the distillation. Reaction commences with the evolution of ammonia when the uiternal temperature reaches 145°. Maintain the... 

Ma.nufa.cture. Nitroguanidine may be made by several methods. In all the processes guanidine nitrate is the iatermediate which is then dehydrated with sulfuric acid. When used ia propellants, the average particle size of nitroguanidine has to be carefully controlled. 

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). 

S. Levmore, PTir Blast Parameters and Other Characteristics of Nitroguanidine and Guanidine Nitrate, TR 4865, PTA, Dover, N.J., 1975. 

Reaction with ammonium salts gives biguanide salts which react further with the ammonium salt forming guanidine salts. Guanidine nitrate [506-93 ] is manufactured by this route (46). 

Guanidine Nitrate (Coll. Vol. i, 293) From ammonium thiocyanate, lead nitrate, and ammonia at 120°. Gockel, Z. angew. Chem. 48, 430 (1935). 

It is strongly recommended that our procedure1 not be used to prepare guanidine nitrate. Mixtures of ammonium nitrate and organic materials not much different from the mixture in the procedure are now used extensively as commercial explosives. The aqueous mixture of Note 101 is similar to some aqueous mixtures used in sizable quantities for rock blasting a confined mixture of this sort is especially hazardous. Only a few laboratories devoted to explosives research have the barricades and remote control devices needed to run this preparation of guanidine nitrate without risk. 

Guanidine nitrate can be bought from Eastman Organic Chemicals and other suppliers. 

Ordnance propellants are required to give the minimum of muzzle flash, smoke and barrel erosion. All these objectives are assisted by adding to the propellant a proportion of nitroguanidine (picrite), made by treating guanidine nitrate with sulphuric acid and brought to very fine particle size by recrystallisation and disintegration. 

Welland A process for making nitroguanidine, an explosive. Cyanamide dimer is reacted with ammonium nitrate to form guanidine nitrate, which forms nitroquanidine when dehydrated by heating with 96 percent sulfuric acid. See also Marquerol and Loriette. 

Guanidine nitrate, warning against synthesis from ammonium nitrate, 43, 48... 

Copper chlorate Guanidine nitrate Halane (l,3-dichloro-5,5-dimethylhydantoin) Hydrogen peroxide solutions... 

J.C. Oxley, J.L. Smith and S. Naik, Determination of Urea Nitrate and Guanidine Nitrate Vapour Pressures by Isothermal Thermogravimetry , submitted to Propellants, Explosives, Pyrotechnics. 

The molecular structure of guanidine nitrate (GN CH6N4O3) is similar to that of TAGN, except that the latter has three additional amino groups ... 

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