Octogen
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| Surname | Octogen | |||||||||||||||
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| Molecular formula | C 4 H 8 N 8 O 8 | |||||||||||||||
| Brief description |
colorless crystals |
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| Molar mass | 296.2 g mol −1 | |||||||||||||||
| Physical state |
firmly |
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| Melting point |
273–281 ° C (decomposition) |
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| As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . | ||||||||||||||||
Octogen is the common name for the explosive cyclotetramethylenetetranitramine , which belongs to the group of nitramines . In US usage it is referred to as homocyclonite or HMX (high molecular weight rdX). The systematic name of HMX is 1,3,5,7-tetranitro-1,3,5,7-tetrazocan.
history
The substance was isolated in 1942 in Germany as a by-product of the technical synthesis of the hexogen (KA process), chemically characterized and investigated by means of explosives, whereby it showed no advantages over the hexogen. At about the same time it was separated and investigated in the USA as a by-product of the identical, new Bachmann process. The structurally similar QDX is created in the manufacture of octogen .
Presentation and extraction
The synthesis of Oktogen starts from hexamethylenetetramine dinitrate , which is converted in the first step by the action of acetic anhydride to 1,5-methylene-3,7-dinitro-1,3,5,7-tetraazacyclooctane. Analogous to the Bachmann process for the production of hexogen , the second step is the production of the target compound using acetic anhydride, nitric acid and ammonium nitrate .
properties
Physical Properties
It exists in four polymorphic forms, of which only the β form is of practical importance. This shape has a particularly high density, which is necessary for a high detonation speed. It forms white crystals that decompose at 273 to 282 ° C. The compound is practically insoluble in water. The solubility in other solvents is comparable to that of Hexogen.
Octogen is an explosive substance within the meaning of the Explosives Act . For the detonation velocity values around 9,110 m · s −1 at a compressed density of 1.89 g · cm −3 are given; it is thus slightly higher than that of Hexogen (8,750 m · s −1 ). In comparison, TNT only detonates at about 6,900 m · s −1 . The explosion heat is 5680 kJ / kg ; 920 l / kg of combustion gases are produced ( normal gas volume ). The lead block bulge is 480 ml / 10 g, the limit diameter in the steel sleeve test is 8 mm. The connection is sensitive to impact and friction . The drop hammer test shows a positive result with an impact energy of 7.5 joules and the friction test with a pin load of 120 N.
Chemical properties
Octogen is a heterocyclic eight-membered ring. Its resistance to sulfuric acid and sodium hydroxide solution is greater than that of hexogen , presumably due to its lower solubility, so that separation methods were based on it. The solubility in acetone is much lower than that of the hexogen, which enables the hexogen to be separated from the octogen by fractional crystallization. Dimethyl sulfoxide or nitromethane is suitable for recrystallization .
use
An exchange of hexogen for octogen results in a gain in performance with high-performance charges (e.g. shaped charges). Mixtures known as octol and containing 25% or 30% of trinitrotoluene are also used.
Toxicology of nitramines
Hexogen has no nitrite effects , it is slowly absorbed from the gastrointestinal tract and probably not at all from the skin . The minimum lethal dose for rats (orally) is 200 mg / kg. But 50–100 mg / kg daily are still tolerated by rats and 50 mg / kg daily by dogs for a few weeks without changes in the blood ; only a little over-excitability was observed. Repeated exposure to hexogen (dust) or impurities in the manufacturing process caused seizures , eye and skin irritation in people .
Nothing is known about the toxicity of octogen. However, it should have a similar central excitatory or convulsive effect as hexogen.
Risk assessment
In 2019, Oktogen was included in the EU's ongoing action plan ( CoRAP ) in accordance with Regulation (EC) No. 1907/2006 (REACH) as part of substance evaluation . The effects of the substance on human health and the environment are re-evaluated and, if necessary, follow-up measures are initiated. The reasons for the uptake of Oktogen were concerns about environmental exposure, exposure of workers and widespread use as well as the possible dangers of carcinogenic and reproductive properties. The re-evaluation should be carried out by Hungary from 2020 .
Individual evidence
- ↑ a b c d Entry on Octogen. In: Römpp Online . Georg Thieme Verlag, accessed on December 22, 2014.
- ↑ a b c d e f g h i j k J. Köhler; R. Meyer, A. Homburg: Explosivstoffe , Tenth, completely revised edition, Wiley-VCH, Weinheim 2008, ISBN 978-3-527-32009-7 , pp. 227-228.
- ↑ a b c Entry on octahydro-1,3,5,7-tetranitro-1,3,5,7-tertazocin in the GESTIS substance database of the IFA , accessed on January 9, 2019(JavaScript required) .
- ↑ Elizabeth P. Burrows, Ernst E. Brueggemann: Reversed-phase gradient high-performance liquid chromatography of nitramine munitions and characterization of munitions process samples by gas chromatography-mass spectrometry , in: Journal of Chromatography A , 1985 , 329 , p. 285 -289, doi : 10.1016 / S0021-9673 (01) 81932-4 .
- ↑ Explosives Act, Appendix I, List of Explosive Substances ( BGBl. 1975 I p. 853 ), to which the law is to be applied in full.
- ↑ Community rolling action plan ( CoRAP ) of the European Chemicals Agency (ECHA): Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine , accessed on March 26, 2019.