Trinitromethane

Trinitromethane, also referred to as nitroform, is a nitroalkane and oxidizer with chemical formula HC(NO2)3. It was first obtained in 1857 as the ammonium salt by the Russian chemist Leon Nikolaevich Shishkov (1830–1908).[2][3] In 1900, it was discovered that nitroform can be produced by the reaction of acetylene with anhydrous nitric acid.[4] This method went on to become the industrial process of choice during the 20th century. In the laboratory, nitroform can also be produced by hydrolysis of tetranitromethane under mild basic conditions.[5]

Trinitromethane[1]
Names
IUPAC name
Trinitromethane
Other names
Nitroform
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.007.489
EC Number
  • 208-236-8
UNII
Properties
CHN3O6
Molar mass 151.04 g/mol
Appearance Pale yellow crystals
Density 1.469 g/cm3
Melting point 15 °C (59 °F; 288 K)
44g/100ml at 20 °C
Acidity (pKa) 0.25 (see text)
Hazards
Main hazards Oxidant, Explosive (esp. in contact with metals), Corrosive.
NFPA 704 (fire diamond)
Related compounds
Related compounds
 Hexanitroethane
Octanitropentane
Tetranitromethane
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Acidity

Trinitromethane as a neutral molecule is colorless. It is highly acidic, easily forming an intensely yellow anion, (NO2)3C−. The pKa of trinitromethane has been measured at 0.17 ± 0.02 at 20 °C, which is remarkably acidic for a methane derivative.[6] Trinitromethane easily dissolves in water to form an acidic yellow solution.

There is some evidence that the anion, which obeys the 4n+2 Hückel rule, is aromatic.[7]

Nitroform salts

Trinitromethane forms a series of bright yellow ionic salts. Many of these salts tend to be unstable and can be easily detonated by heat or impact.

The potassium salt of nitroform, KC(NO2)3 is a lemon yellow crystalline solid that decomposes slowly at room temperatures and explodes above 95 °C. The ammonium salt is somewhat more stable, and deflagrates or explodes above 200 °C. The hydrazine salt, hydrazinium nitroformate is thermally stable to above 125 °C and is being investigated as an ecologically friendly oxidizer for use in solid fuels for rockets.

References
  1. Budavari, Susan, ed. (1996), The Merck Index: An Encyclopedia of Chemicals, Drugs, and Biologicals (12th ed.), Merck, ISBN 0911910123, 9859.
  2. For biographical information about Leon Nikolaevich Shishkov, see The Free Dictionary
  3. See:
  4. The Italian chemist Adolfo Baschieri discovered that nitroform (Italian: nitroformio) could be produced from acetylene (acetilene) and nitric acid (acido nitrico).
  5. Gakh, A. A.; Bryan, J. C.; Burnett, M. N.; Bonnesen, P. V. (2000). "Synthesis and structural analysis of some trinitromethanide salts" (PDF). Journal of Molecular Structure. 520 (1–3): 221–228. doi:10.1016/S0022-2860(99)00333-6.
  6. Novikov, S. S.; Slovetskii, V. I.; Shevelev, S. A.; Fainzilberg, A. A. (1962). "Spectrophotometric Determination of the Dissociation Constants of Aliphatic Nitro Compounds". Russian Chemical Bulletin. 11 (4): 552–559. doi:10.1007/BF00904751.
  7. Cioslowski, J.; Mixon, S. T.; Fleischmann, E. D. (1991). "Electronic structures of trifluoro-, tricyano-, and trinitromethane and their conjugate bases". Journal of the American Chemical Society. 113 (13): 4751–4755. doi:10.1021/ja00013a007.
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