Nitroguanidine
Nitroguanidine - sometimes abbreviated NQ or NGu - is a colorless, crystalline solid that decomposes at, without melting. Nitroguanidine is an extremely insensitive but powerful high explosive. Nitroguanidine is used as an energetic material, precursor for insecticides, and for other purposes.
Manufacture
Nitroguanidine is produced worldwide on a large scale starting with the reaction of dicyandiamide with ammonium nitrate to afford the salt guanidinium nitrate, which is then nitrated by treatment with concentrated sulfuric acid at low temperature.The guanidinium nitrate intermediate may also be produced via the Boatright–Mackay–Roberts process, in which molten urea is reacted with molten ammonium nitrate in the presence of silica gel. This process had been commercialized because of its attractive economic features.
Uses
Explosives
Nitroguanidine has been in use since the 1930s as an ingredient in triple-base gun propellants in which it reduces flame temperature, muzzle flash, and erosion of the gun barrel but preserves chamber pressure due to high nitrogen content. Its extreme insensitivity combined with low cost has made it a popular ingredient in insensitive high explosive formulations.The first triple-base propellant, featuring 20-25% of nitroguanidine and 30-45% nitroglycerine, was developed at the Dynami Nobel factory at Avigliana and patented by its director Dr. Modesto Abelli in 1905.
Nitroguanidine's explosive decomposition may be given by the following idealized equation: