Urea nitrate
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| General | ||||||||||
| Surname | Urea nitrate | |||||||||
| Molecular formula | CH 5 N 3 O 4 | |||||||||
| Brief description |
colorless crystals |
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| properties | ||||||||||
| Molar mass | 123.07 g mol −1 | |||||||||
| Physical state |
firmly |
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| density |
1.69 g cm −3 |
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| Melting point |
157 ° C (decomposition) |
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| solubility |
bad in cold and good in warm water |
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| safety instructions | ||||||||||
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| As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . | ||||||||||
Urea nitrate (chemical structure H 2 N – CO – NH 2 · HNO 3 ) is the skin and mucous membrane irritating , explosive urea salt of nitric acid.
Extraction and presentation
Urea nitrate can be obtained by careful Add a saturated solution of urea in nitric acid to the precipitated crystals are shown, followed by filtration. Since the reaction can be highly exothermic , especially at high acid concentrations , one should always ensure that the reaction mixture is sufficiently cooled when synthesizing urea nitrate.
properties
Physical Properties
Urea nitrate forms colorless crystals with a melting point of 152 ° C, which tend to decompose explosively.
| Educational energy | −4454.8 kJ / kg |
| Enthalpy of formation | −4575.7 kJ / kg |
| Oxygen balance | −6.5% |
| Nitrogen content | 34.14% |
| Normal gas volume | 910 l / kg |
| Explosion heat | 3213 kJ / kg (H 2 O (l)) 2458 kJ / kg (H 2 O (g)) |
| Specific energy | 755 kJ / kg (77.0 mt / kg) |
| Lead block bulge | 270 cm 3 / 10g |
| Deflagration point | 186 ° C |
| Steel sleeve test | no reaction at 1 mm diameter |
| Sensitivity to impact | no reaction up to 50 Nm impact energy |
| Rubbing sensitivity | no reaction up to 353 N pin load |
Chemical properties
Since urea nitrate is the salt of a weak base and a strong acid , it reacts acidic in aqueous solution. It is easily soluble in hot water.
Mixtures with magnesium powder can react spontaneously with strong heat and gas development (including NO x ). Similar dangerous reactions are to be expected from mixtures with other base metals and other reducing agents.
Urea nitrate tends to decompose explosively, especially in the presence of catalysts such as heavy metal ions, but also due to friction or heat.
use
Urea nitrate is used in up to five percent aqueous solution as a metal cleaning or pickling agent due to the nitric acid released in the solution . Due to the nitric acid it contains, urea nitrate is suitable as a reactant for explosives . In the Middle East, it is increasingly being used directly by assassins as an explosive; When it is initially ignited, it develops 70 percent of the explosive power of TNT , but is considerably cheaper and easier to manufacture. Due to its solubility in water and, above all, its corrosive effect and its thermal instability (decomposition from 152 ° C), it is unsuitable as a military explosive and, besides its unprofessional use, is rarely used in attacks.
Legal
Urea nitrate is dry or with less than 20% water by mass an explosive within the meaning of Article 1 Paragraphs 2 and 3 of Directive 93/15 / EEC and the Explosives Act .
literature
- Roland Ionas Bialke: The demolition master's textbook. Collected knowledge about explosives from the clandestine hobby demolition master scene, Books on Demand GmbH, Norderstedt 2008, ISBN 978-3-8370-4729-5 .
Web links
- Explosives production in the Middle East
- About the physico-chemical properties of urea nitrate (accessed on May 14, 2020)
- The life-threatening carelessness "Internet bomb construction" (accessed on May 14, 2020)
- Law on Explosive Substances (accessed on May 14, 2020)
- Detection and identification of explosives with chemical rapid tests (accessed on May 14, 2020)
Individual evidence
- ↑ a b Entry on urea nitrate. In: Römpp Online . Georg Thieme Verlag, accessed on December 28, 2014.
- ↑ a b c d e Entry on urea nitrate in the GESTIS substance database of the IFA , accessed on January 8, 2018(JavaScript required) .
- ↑ a b c d e f g h i j k l Josef Köhler, Rudolf Meyer, Axel Homburg: Explosivstoffe. 10th edition, Wiley-VCH, 2008, ISBN 978-3-527-32009-7 , p. 155. doi: 10.1002 / 9783527623402.ch8
- ↑ Law on explosive substances (Sprengstoffgesetz - SprengG), Annex III List of explosives according to § 3 Paragraph 1 No. 1 pdf ( Memento of February 16, 2016 in the Internet Archive )