Ammonium dinitramide
| Names | |
|---|---|
| IUPAC name
Ammonium dinitramide
| |
| Other names
ADN
Dinitramide ammonium salt | |
| Properties | |
| H4N4O4 | |
| Molar mass | 124.06 g/mol |
| Appearance | White solid |
| Odor | Odorless |
| Density | 1.81 g/cm3 |
| Melting point | 93 °C (199 °F; 366 K) |
| Boiling point | 160 °C (320 °F; 433 K) (decomposes) |
| 140 g/100 ml (-15 °C) 168.1 g/100 ml (-10 °C) 225.7 g/100 ml (0 °C) 356.6 g/100 ml (20 °C)[1] | |
| Solubility | Soluble in acetone, butanol |
| Vapor pressure | ~0 mmHg |
| Thermochemistry | |
| Std enthalpy of
formation (ΔfH |
14,398.1 kJ/mol |
| Hazards | |
| Safety data sheet | None |
| Related compounds | |
| Related compounds
|
Ammonium nitrate |
| Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
| Infobox references | |
Ammonium dinitramide (ADN) is the ammonium salt of dinitraminic acid, having the chemical formula NH4N(NO2)2. It is a much more powerful oxidizer than ammonium nitrate.
Contents
Properties
Chemical
Ammonium dinitramide decomposes when heated to give off water vapors, nitrogen and oxygen:
- NH4N(NO2)2 → 2 N2 + 2 H2O + O2
Small amounts of nitrous oxide and nitric oxide are also produced.
Physical
Ammonium dinitramide is a colorless crystalline solid.
Explosive
Ammonium dinitramide may explode when exposed to strong shock or very high temperatures, but overall it is stable. Detonation velocity is around 7,000 m/s.[2]
Availability
As this compound is still researched, ADN is not currently in any supplier's stock, not even Sigma-Aldrich/Merck don't have it.
One company allegedly sells crystalline and prilled ADN.
Preparation
A route to obtain ammonium dinitramide involves potassium sulfamate, a salt of sulfamic acid. The potassium sulfamate salt is obtained by neutralizing sulfamic acid with potassium hydroxide or carbonate, then the solution is dried and solid potassium sulfamate is collected. In a reaction flask, a nitrating mixture consisting of 106 ml fuming nitric acid and 26.4 ml conc. sulfuric acid are added, and the flask is cooled to -40 °C. The stirring is turned on, and the dry potassium sulfamate (40 g) is slowly added in 4 g portions for 10 min. As the reaction progresses, the viscosity of the mixture increases, as the potassium sulfate precipitates. Stirring continues for 30 more minutes. The resulting mixture is poured in crushed ice, and neutralized with potassium hydroxide, under cooling. The product is filtrate and extracted using acetone. The yield of this process is almost 50%. The ammonium dinitramide is obtained from the potassium salt via metathesis with a soluble ammonium salt.[3][4]
A route to this compounds involves dissolving nitramide in dry and cold acetonitrile (-10 °C), followed by the addition of nitronium tetrafluoroborate. The mixture is stirred for 10 min, after which an etheric solution of ammonia in isopropanol is added to the acetonitrile solution. The solvent is removed and the ADN is recrystallized from butanol.[5]
The reaction of dinitrogen pentoxide with ammonia in dichloromethane -78 °C, will give ammonium dinitramide. To obtain the compound, the reaction product is warmed to room temperature, the CH2Cl2 is removed then the compound is extracted with acetone. Further purification can be achieved by recrystallizing the compound from butanol. Total yield is 15%. If the reaction takes place at higher temperatures, the yield will be lower.[6]
A synthesis without a source is given on Wikipedia, but due to the lack of references it's unclear if it actually works: Ammonium dinitramide can be synthesized from ammonium nitrate, anhydrous nitric acid, and fuming sulfuric acid containing 20% free sulfur trioxide. A base other than ammonia must be added before the acid dinitramide decomposes. The final product is obtained by fractional crystallization.
Projects
- Rocket fuel and propellant
- Oxidizer
Handling
Safety
Ammonium dinitramide is a powerful oxidizer and may explode under strong heating or shock. Handle it with care.
Storage
Ammonium dinitramide should be kept in closed plastic bottles, away from acids and anything combustible.
Disposal
Carefully heating the compound will cause it to decompose. For safety, you can mix it with a non-flammable material, like gypsum before heating.
References
- ↑ https://pubs.acs.org/doi/abs/10.1021/je0600698
- ↑ http://www.eurenco.com/content/explosives/defence-security/oxidizers-energetic-polymers/adn/
- ↑ https://patents.google.com/patent/US5976483
- ↑ https://www.researchgate.net/publication/288230194_Safety_of_Ammonium_Dinitramide_Synthesis_vs_Size_of_a_Commercial_Production_Scale
- ↑ Bottaro, Jeffrey C.; Penwell, Paul E.; Schmitt, Robert J.; Journal of the American Chemical Society; vol. 119; nb. 40; (1997); p. 9405 - 9410
- ↑ Bottaro, Jeffrey C.; Penwell, Paul E.; Schmitt, Robert J.; Journal of the American Chemical Society; vol. 119; nb. 40; (1997); p. 9405 - 9410
