Nitroguanidines

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). 

D. Price and A. R. Clairmont, Jr., "Explosive Behavior of Nitroguanidine," in Proceedings of the 12th Symposium on Combustion, Combustion Institute, Pittsburgh, Pa., 1969, p. 761. 

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

J. Savitt, "Some Properties and Uses of Nitroguanidine," paper no. 38 in Proceedings of Institutefor Chemie der Traub-und-Explosivestaffe, ICT, International Jahrsteig, Kadsuike, ERG, 1985. 

V. Milan and co-workers. The Preparation of High Bulk Density Nitroguanidine, Rpt. 3037, NAVORD, Washington, D.C., 1957. 

C. E. Duerr and co-workers, Nitroguanidine Process Optimisation, ARLCB-CR-85031, ARDEC, Dover, N.J., Sept. 1985. 

The more important methods of preparation of diazomethane include those from nitrosomethylurea, nitrosomcthylurethane, N-nitroso-/3-methylaminoisobutyl methyl ketone, and 1-methyl-l-nitroso-3-nitroguanidine. ... 

NITROGEN TRIOXIDE NITROGLYCERIN NITROGUANIDINE NITROHYDROCHLORIC ACID NITROMETHANE... 

It is interesting to note that the acyclic analog, nitroguanidine, exists in the symmetrical form 288 rather than as 289. Structure 288 has been established by ultraviolet and proton nuclear magnetic resonance spectroscopy. X-ray crystallography, dipole moments, and ipK measurements (see reference 367 and references therein). 

Several lesser known nitrating agents, which have been used on a lab scale are metal nitrates in the presence of acetic acid or acetic anhydride, tetranitromethane and hexanitroethane in an alkaline medium, and nitroguanidine in soln in sulfuric acid, used for the nitration of aromatic... 

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