DubaiAmateurRocketry
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easiest ADN synthesis ?
Ammonium dinitramide performs better than most oxidizers today, so i really want to make it, or at least, know how to make it.
And, I am deciding on mass producing it next year, around 15 kg, if the cost is not too high. If i can afford it, i will try it out on an engine and
sharing the results with you all.
So, whats the easiest way to make AP ? some ways seems need some chemicals i never even heard before ? and some other needs some strong acids ? can
any one share some good files on easy synthesis of ADN please ?
loves.
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hyfalcon
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First page on google patents. You need to do a little more due diligence on your own about searching.
https://www.google.com/patents/US5714714?pg=PA2&dq=ammon...
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Dany
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this is a better and simpler method for preparing dinitramide derivatives
http://www.google.com/patents/US5976483
Dany.
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AndersHoveland
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There are several possible routes:
| Quote: | Preparation A
17g potassium sulfamate was added in small portions (0.5- 1 g ) to a mixture of 16mL 98% concentrated sulfuric acid and 45 mL fuming nitric acid, with
continual stirring of the mixture. The mixture was kept between (minus) -35 and -45 degC, using an ice bath consisting of dry ice and methylene
chloride. (The reaction temperature need only be below -25 degC, if care is taken to avoid overheating) The viscocity increased as the reaction
proceeded, and potassium bisulfate precipitated. Dinitramidic acid is not stable under acidic conditions so the pH must subsequently be raised to
avoid decomposition. A solution of cold potassium hydroxide was slowly added to the reaction mixture, again with constant stirring, with the mixture
still cooled in the ice bath. The temperature was not allowed to rise above 0degC. The solution becomes a greenish yellow color, indicating that the
acids in solution are nearly neutralized. Further solution of potassium hydroxide was added until the pH reached 8 (weakly basic).
The reaction mixture allowed to evaporate until dry. The dry powder remaining was extracted with acetone, then 100mL pure isopropyl alcohol was added
to the acetone solution. The mixture is again allowed to evaporate. As the acetone first evaporates out, the potassium dinitramide will precipitate
out of the isopropyl alcohol. The crystals were filtered from the solution and dried in an oven at 70 degC. 10.7 grams (60% yield) of potassium
dinitramide is obtained from this procedure. The crystals melt at 130.5 degC.
1g potassium dinitramide and 1g ammonium sulfate were individually dissolved in two separate portions of 2mL water each. The two solutions were then
mixed, resulting in a white precipitate of potassium sulfate. 20mL of isopropyl alcohol was added to the solution, then the potassium sulfate was
filtered out. The remaining solvent that passed through the filter was evaporated under reduced pressure. The product from the evaporation was
slightly moist. It was next dissolved in more isopropyl alcohol. This solution was poured into petroleum ether, at which point ammonium dinitramide
precipitated out. The precipitate was filtered out and dried at 50degC. 0.68 grams ammonium dinitramide is obtained from this procedure (80% yield).
The crystals have a melting point of 91 degC.
Note
Maximum yields of dinitramidic acid were obtained when he mole ratios of sulfuric to nitric acid are 2 : 7, with a nitration time between 23-25
minutes.
Preparation B
Alternatively, ammonium sulfamate may be used in the nitration, and ammonium hydroxide can then be used to neutralize the mixture. This more direct
procedure, however, gives only a 40% yield, and the ammonium dinitramide will contain ammonium nitrate impurities, which lowers the observed melting
point to 86degC.
Sulfamic acid has the formula HOSO2NH2, and its salts can be prepared from the pyrosulfate (K2S2O7) with dry NH3 gas, or by direct reaction between
SO3 and NH3 (reaction is extremely violent!)
Preparation C
Into a 250 mL Erlenmeyer flask combine 3 g of potassium dinitramide and 3 g of finely powdered ammonium sulfate. Add 100 mL of isopropyl alcohol and
heat the flask, while stirring, until all of the solids dissolve. Place the flask in a cold water bath to precipitate the byproduct of potassium
sulfate. Filter to remove the crystals of sulfate and gently heat the filtrate to concentrate it to a fraction of its volume. Pour the concentrate
into a beaker containing an excess of petroleum ether to precipitate ammonium dinitramide. Filter to collect the crystals and dry them in an oven at
50 C.
Preparation D
Prepare a mixture of 7.5 g of ammonium N-nitrourethane suspended in 200 mL of methylene chloride. Cool this mixture to -50 C in an acetone-dry ice
bath. Prepare a second mixture of 45 mL of dinitrogen tetroxide in 200 mL of dry methylene chloride. Cool this mixture to -78 C in an acetone-dry ice
bath. Bubble ozone into the second mixture, while stirring, until it is a dark blue color. While bubbling the ozone allow the mixture to warm up to
-30 C. The mixture will now consist of dinitrogen pentoxide in methylene chloride.
Combine the two mixtures and let them sit for 1 hour. During this time the temperature of the reaction mixture is allowed to warm to -30 C. Bubble
ammonia gas into the mixture to raise the pH to 10. Filter to collect any insoluble material and add it to a beaker containing 150 mL of acetonitrile.
Stir the acetonitrile mixture for 20 minutes before filtering to remove any remaining undissolved impurities.
The filtrate is poured into a 2.5cm by 10cm column containing 230-400 mesh silica gel. The ammonium dinitramide is eluted by adding acetonitrile. The
resulting eluted filtrate is concentrated to 30 mL and treated with 30 mL of chloroform to precipitate pure ammonium dinitramide. The crystals are
filtered to collect them and allowed to dry. Final yield is about 4 g or 60%.
Preparation E
Prepare a mixture of 8.8 g of hydrofluoric acid and 40 g of ethylnitrate in 300 mL of dry nitromethane. Place this mixture in a salt-ice bath and cool
to 10 C. Slowly add 100 g of boron trifluoride to the mixture while keeping the temperature between 10 and 15 C. A few minutes after the addition
filter to collect the crystals of nitronium tetrafluorate that form. Wash the crystals with two 400 mL portions of a 1:1 mixture of methylene chloride
and nitromethane, and then with one 400 mL portion of methylene chloride.
Place the nitronium tetrafluorate crystals into a beaker containing 400 mL of methylene chloride. Cool the contents to -78 C in an acetone-dry ice
bath. Bubble 35 g of anhydrous ammonia into the beaker over a period of 2 hours while stirring. Continue stirring the mixture for 12 hours while
allowing it to warm to room temperature. Filter to collect the solid material and wash it with 400 mL of methylene chloride. Add the crystals to 150
mL of acetone and stir for 1 hour. Add 150 mL of ethyl acetate to the mixture and filter to remove any undissolved material. Gently heat the filtrate
solution to dryness to obtain crude ammonium dinitramide. The ammonium dinitramide can be purified by recrystallizing from n-butanol. Final yield is
about 5.5 g or 21% yield. |
Ammonium dintramide has also been obtained by direct reaction of N2O5 with anhydrous NH3.
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Bert
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http://www.jatm.com.br/papers/vol1_n2/JATMv1n2_p153-160_ADN-...
It seems to be rather more expensive material, and in use, more technicly challenging than ammonium perchlorate based systems. The slightly higher
specific impulse is attractive, but outside of military and space applicarions, is it worth the expense?
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Anatol Rapoport was a Russian-born American mathematical psychologist (1911-2007).
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