Dunnite, also known as Explosive D or systematically as ammonium picrate, is an explosive developed in 1906 by US Army Major Beverly W. Dunn, who later served as chief inspector of the Bureau of Transportation Explosives.[2][3] Ammonium picrate is a salt formed by reacting picric acid and ammonia. It is chemically related to the more stable explosive trinitrotoluene (TNT).

Dunnite
Names
IUPAC name
Ammonium 2,4,6-trinitrophenolate
Other names
Ammonium picrate; Picratol; 2,4,6-Trinitrophenol ammonium salt; Ammonium picronitrate; Explosive D
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.004.582 Edit this at Wikidata
EC Number
  • 205-038-3
UNII
  • InChI=1S/C6H3N3O7.H3N/c10-6-4(8(13)14)1-3(7(11)12)2-5(6)9(15)16;/h1-2,10H;1H3 ☒N
    Key: PADMMUFPGNGRGI-UHFFFAOYSA-N ☒N
  • InChI=1/C6H3N3O7.H3N/c10-6-4(8(13)14)1-3(7(11)12)2-5(6)9(15)16;/h1-2,10H;1H3
    Key: PADMMUFPGNGRGI-UHFFFAOYAZ
  • C1=C(C=C(C(=C1[N ](=O)[O-])[O-])[N ](=O)[O-])[N ](=O)[O-].[NH4 ]
Properties
C6H6N4O7
Molar mass 246.135 g·mol−1
Density 1.719 g/cm3[1]
Melting point 265 °C (509 °F; 538 K)[1]
10 g/L (20 °C)
Hazards
GHS labelling:
GHS01: ExplosiveGHS07: Exclamation mark
Danger
H201, H315, H317, H319
P210, P230, P240, P250, P261, P264, P272, P280, P302 P352, P305 P351 P338, P321, P332 P313, P333 P313, P337 P313, P362, P363, P370 P380, P372, P373, P401, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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History

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Ammonium picrate was proposed for use as a component in gunpowder by Brugère and Abel as early as 1869: the former proposed to mix 54% of it with 46% of saltpetre while the latter, 60% with 40%.[4] Their compositions gave less smoke and were more energetic than black powder but neither was adopted by any military, even though in the 1890s "semi-smokeless" powder compositions featuring ammonium picrates were sold commercially in the US.[5] It also was a minor component of the Peyton powder made by the California Powder Works which was procured by the US military in the same period.[5]

It was the first explosive used in an aerial bombing operation in military history, performed by Italian pilots in Libya in 1911.[6] It was used extensively by the United States Navy during World War I.[7]

Though Dunnite was generally considered an insensitive substance, by 1911 the United States Army had abandoned its use in favor of other alternatives.[8] The Navy, however, used it in armor-piercing artillery shells and projectiles, and in coastal defense.

By the end of WWI a pound of ammonium picrate cost US government 64 cents, while TNT cost 26.5 c/lb, ammonium nitrate used in amatol only 17.5 c/'b and black powder about 25 c/lb.[9]

Dunnite typically did not detonate on striking heavy armor. Rather, the encasing shell would penetrate the armor, after which the charge would be triggered by a base fuze.

During WWII, it was gradually replaced by RDX-based Composition A-3.[10]

In 2008 caches of discarded Dunnite in remote locations were mistaken for rusty rocks at Cape Porcupine, Newfoundland and Labrador, Canada.[11][12]

Dunnite can be used as a precursor to the highly stable explosive TATB (1,3,5-triamino-2,4,6-trinitrobenzene), by first dehydrating it to form picramide (attaching the ammonia as an amine group instead of an ion) and then further aminating it, using 1,1,1-trimethylhydrazinium iodide (TMHI) made from unsymmetrical dimethylhydrazine rocket fuel and methyl iodide. Thus, surplus materials that would have to be destroyed when no longer needed are converted into a high value explosive.[13][14]

References

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  1. ^ a b Record of Ammoniumpikrat in the GESTIS Substance Database of the Institute for Occupational Safety and Health, accessed on 24. Nov. 2007.
  2. ^ War Records Committee of the Alumni Association (1920), Technology's War Record: An Interpretation of the Contribution Made by the Massachusetts Institute of Technology, Its Staff, Its Former Students and Its Undergraduates to the Cause of the United States and the Allied Powers in the Great War, 1914–1919, Cambridge, MA: Massachusetts Institute of Technology, p. 364
  3. ^ "Dunnite Smashes Strongest Armor", The New York Times, August 18, 1907
  4. ^ Guttmann, Oscar (1895). The Manufacture of Explosives: A Theoretical and Practical Treatise on the History, the Physical and Chemical Properties, and the Manufacture of Explosives. Whittaker and Company.
  5. ^ a b Gelder, Arthur Pine Van; Schlatter, Hugo (1927). History of the Explosives Industry in America. Columbia University Press. ISBN 978-0-231-91436-9.
  6. ^ [1], La Stampa, November 2, 1911
  7. ^ Dunnite, Firstworldwar.com
  8. ^ Ridicule Spy Story: Army Abandoned the Use of Dunnite Years Ago, Officers Say, The New York Times, August 8, 1911
  9. ^ Department, United States War (1919). America's Munitions 1917-1918: Report of Benedict Crowell, the Assistant Secretary of War, Director of Munitions. U.S. Government Printing Office.
  10. ^ Rowland, Buford (1953). U.S. Navy Bureau of Ordnance in World War II. Bureau of Ordnance, Department of the Navy.
  11. ^ Moore, Oliver (2008-09-11). "Family makes explosive discovery on Labrador shore". The Globe and Mail. Archived from the original on 2017-01-09.
  12. ^ "Beachcombing Labrador family carries home wartime explosive". Canadian Broadcasting Corporation. 2008-09-10. Retrieved 2017-01-07.
  13. ^ Mitchell, Alexander R.; Pagoria, P. F.; Schmidt, R D. (10 November 1995). Conversion of the Rocket Propellant UDMH to a Reagent Useful in Vicarious Nucleophilic Substitution Reactions (PDF) (Technical report). Lawrence Livermore National Laboratory. S2CID 54794595. UCRL-JC-122489.
  14. ^ Mitchell, Alexander R.; Coburn, Michael D.; Schmidt, Robert D.; Pagoria, Philip F.; Lee, Gregory S. (2002). "Advances in the chemical conversion of surplus energetic materials to higher value products". Thermochimica Acta. 384 (1–2): 205–217. Bibcode:2002TcAc..384..205M. doi:10.1016/S0040-6031(01)00806-1.