Dunnite
Chemical compound
From Wikipedia, the free encyclopedia
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).
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| Names | |
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| 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) |
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| ChemSpider | |
| ECHA InfoCard | 100.004.582 |
| EC Number |
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PubChem CID |
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| UNII | |
CompTox Dashboard (EPA) |
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| 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: | |
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| 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
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/lb 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]