Nitroguanidine

Chemical compound From Wikipedia, the free encyclopedia

Nitroguanidine - sometimes abbreviated NQ or NGu - is a colorless, crystalline solid that decomposes at 239 °C (462 °F), without melting. Nitroguanidine is an extremely insensitive but powerful high explosive. Nitroguanidine is used as an energetic material (propellant or high explosive), precursor for insecticides,[citation needed] and for other purposes.

Quick facts Names, Identifiers ...
Nitroguanidine
Names
IUPAC name
1-Nitroguanidine
Other names
Picrite
Identifiers
3D model (JSmol)
03, 126
ChEBI
ChemSpider
ECHA InfoCard 100.008.313 Edit this at Wikidata
RTECS number
  • MF4600000
UNII
  • InChI=1S/CH4N4O2/c2-1(3)4-5(6)7/h(H4,2,3,4) checkY
    Key: IDCPFAYURAQKDZ-UHFFFAOYSA-N checkY
  • InChI=1/CH4N4O2/c2-1(3)4-5(6)7/h(H4,2,3,4)
    Key: IDCPFAYURAQKDZ-UHFFFAOYAN
  • NC(N)=N[N+]([O-])=O
Properties
(NH2)2CNNO2
Molar mass 104.069 g·mol−1
Appearance Colorless crystalline solid
Density 1.77 g/cm3
Melting point 239 °C (462 °F; 512 K)[1] decomposes
  • 0.12 g/100mL (0 °C (32 °F; 273 K))
  • 0.42 g/100mL (25 °C (77 °F; 298 K))
  • 8.25 g/100mL (100 °C (212 °F; 373 K))[2]
Solubility in Sulfuric acid 10.9 g/100mL (45% H2SO4)[2]
Acidity (pKa) 12.2 (in 1 M NaCl at 24 °C (75 °F; 297 K))[3]
Basicity (pKb) 15[4]
Explosive data[2]
Shock sensitivity
  • 4.4 lb (2 kg) weight, 19 in (47 cm) (Bureau of Mines apparatus)
  • 1 lb (0.45 kg) weight, 26 in (66 cm) (Picatinny Arsenal apparatus)
  • Unaffected - Rifle bullet impact.
Friction sensitivity Insensitive
Detonation velocity
  • 5,360 m/s (17,600 ft/s) (at specific gravity (sp. gr.) 1)
  • 7,650 m/s (25,100 ft/s) (at sp. gr. 1.5)
RE factor 1.01 (Trauzl test)
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
 Explosive when dry.
GHS labelling:(Stabilized with 25% water)[1]
GHS02: Flammable
Danger
H228
P210, P240, P241, P280, P370+P378
NFPA 704 (fire diamond)
[5]
NFPA 704 four-colored diamondHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 0: Will not burn. E.g. waterInstability 4: Readily capable of detonation or explosive decomposition at normal temperatures and pressures. E.g. nitroglycerinSpecial hazards (white): no code
2
0
4
7 mg/m3[1] (TWA)
Lethal dose or concentration (LD, LC):
10200 mg/kg (oral, rat)[5]
Related compounds
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Manufacture

Nitroguanidine is produced worldwide on a large scale starting with the reaction of dicyandiamide (DCD) with ammonium nitrate to afford the salt guanidinium nitrate, which is then nitrated by treatment with concentrated sulfuric acid at low temperature.[6]

[C(NH2)3]NO3 → (NH2)2CNNO2 + H2O

The guanidinium nitrate intermediate may also be produced via the Boatright–Mackay–Roberts (BMR) process, in which molten urea is reacted with molten ammonium nitrate in the presence of silica gel.[6][7] This process had been commercialized because of its attractive economic features.

2 NH2CONH2 + NH4NO3 → [C(NH2)3]NO3 + 2 NH3 + CO2

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.).[8]

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 (1859-1911) in 1905.[9][10]

Nitroguanidine's explosive decomposition may be given by the following idealized equation:[citation needed]

3 O2N−N=C(NH2)2 → 3 CO2 + 4 N2 + 4 NH3

Pesticides

Nitroguanidine derivatives are used as insecticides, having a comparable effect to nicotine. Derivatives include clothianidin, dinotefuran, imidacloprid, and thiamethoxam.

Structure

It has been confirmed by NMR spectroscopy, and both x-ray and neutron diffraction that nitroguanidine exclusively exists as the nitroimine tautomer both in solid state and solution.[11][12][13]

Related compounds

The methylated and nitrosylated derivative methylnitronitrosoguanidine is used to mutagenize bacterial cells for biochemical studies.[citation needed]

References

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