Nitroguanidine - sometimes abbreviated NGu - is a colorless, crystalline solid that melts at 257 °C and decomposes at 254 °C. Nitroguanidine is an extremely insensitive but powerful high explosive. Wetting it with > 20 wt.-% water effects desensitization from HD 1.1 down to HD 4.1 (flammable solid). Nitroguanidine is used as an energetic material, i.e., propellant or high explosive, precursor for insecticides, and for other purposes.

Manufacture

Nitroguanidine is produced worldwide on a large scale starting with the reaction of dicyandiamide (DCD) with

ammonium nitrate Ammonium nitrate is a chemical compound with the formula . It is a white crystalline salt consisting of ions of ammonium and nitrate. It is highly soluble in water and hygroscopic as a solid, but does not form hydrates. It is predominantly us ...

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 (BMR) process, in which molten

urea Urea, also called carbamide (because it is a diamide of carbonic acid), is an organic compound with chemical formula . This amide has two Amine, amino groups (–) joined by a carbonyl functional group (–C(=O)–). It is thus the simplest am ...

is reacted with molten ammonium nitrate in the presence of

silica gel Silica gel is an amorphous and porosity, porous form of silicon dioxide (silica), consisting of an irregular three-dimensional framework of alternating silicon and oxygen atoms with nanometer-scale voids and pores. The voids may contain wate ...

. 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 (e.g AFX-453, AFX-760, IMX-101, AL-IMX-101, IMX-103, etc.). The first triple-base propellant, featuring 20-25% of nitroguanidine and 30-45% nitroglycerine, was developed at the Dynami Nobel factory at

Avigliana Avigliana (; ; ) is a town and (municipality) in the Metropolitan City of Turin in the Piedmont region of Italy, with 12,129 inhabitants as of 1 January 2023. It lies about west of Turin in the Susa valley, on the motorway going from Turin to ...

and patented by its director Dr. Modesto Abelli (1859-1911) in 1905. Nitroguanidine's explosive decomposition may be given by the following idealized equation: :

Pesticides

Nitroguanidine derivatives are used as

insecticide Insecticides are pesticides used to kill insects. They include ovicides and larvicides used against insect eggs and larvae, respectively. The major use of insecticides is in agriculture, but they are also used in home and garden settings, i ...

s, having a comparable effect to

nicotine Nicotine is a natural product, naturally produced alkaloid in the nightshade family of plants (most predominantly in tobacco and ''Duboisia hopwoodii'') and is widely used recreational drug use, recreationally as a stimulant and anxiolytic. As ...

. Derivatives include clothianidin, dinotefuran, imidacloprid, and thiamethoxam.

Structure

Following several decades of debate, it could be confirmed by NMR spectroscopy, and both

x-ray An X-ray (also known in many languages as Röntgen radiation) is a form of high-energy electromagnetic radiation with a wavelength shorter than those of ultraviolet rays and longer than those of gamma rays. Roughly, X-rays have a wavelength ran ...

and

neutron diffraction Neutron diffraction or elastic neutron scattering is the application of neutron scattering to the determination of the atomic and/or magnetic structure of a material. A sample to be examined is placed in a beam of Neutron temperature, thermal or ...

that nitroguanidine exclusively exists as the nitroimine tautomer both in solid state and solution.S. Choi, Refinement of 2-Nitroguanidine by Neutron Powder Diffraction, ''Acta Crystallogr. B'' 1981, ''37'', 1955-195

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Related compounds

The nitrosoylated derivative, nitrosoguanidine, is used to mutagenize bacterial cells for biochemical studies.

References

{{reflist Explosive chemicals Propellants