Sciencemadness Discussion Board

DPT: an amateur vs pros

caterpillar - 4-3-2012 at 14:35

One wise boy found a way to make DPT with good yield. Here is the link: http://imploders.ru/dinitro-pentametilentetramin/2/ .Brief interpretation for these, who do not know russian. 50 ml HNO3 70% + 20 ml H2SO4 92,4% cooled down to 0 C. Into this mixture 25 gr sulphamine acid NH3SO3 was added witn continious stirring. After 20 minutes hexamine dinitrate 27 gr was added in small portions with stirring, temperature was kept below 15 C. After 40 minutes at 5-10 C mixture was slowly heated up to 30 C. Heating was stopped, but temperature was growing up. Wheh it had reached 40 C, mixture was cooled down to 35 C. This op has been made few times. When an exotermic reaction had finished (one our after initial heating), reaction mixture was diluted 1:2 by half-frosen solution of NH4NO3 (10%). Then acid was neutralised with NaHCO3 to pH 6. During this op DPT precipitated. It was washed by water and isopropil alcohole. Author claims that yield is above 90 %.

AndersHoveland - 17-3-2012 at 22:36

DPT (3,7-dinitro-1,3,5,7 tetraazabicyclo [3,3,1] nonane)

The best method of obtaining DPT consists in introducing hexamine dinitrate to 90% sulfuric acid at 8-15 °C. After 45 minutes all is poured on ice and the solution is filtrated. The filtrate is neutralized with 28% conc. ammonia to pH = 5.5-6.5 and DPT precipitated.

0045.GIF - 1kB

Since DPT is itself an explosive and can be prepared from a mixed H2SO4/HNO3 nitration on hexamine, it is surprising that this compound is not more popular.


Here is a translation of Experiment number 1 from that russian page in the link:
Quote:

Dinitro-pentamethylenetetramine
To 100 ml of HNO3 (density 353g/ml or 53% conc.), cooled to +10 °C, was sprinkled 50g of sulfamic acid, a temperature rise is not observed. After mixing with stirring at 10° C for 30 minutes, 53g of DNU was made, the temperature is kept below 20 °. After holding at this temperature for 20 minutes, the reaction mixture was warmed to 30 °, then external heating was discontinued, but the reaction continued to increase in temperature by itself. After reaching 35-36 ° it was carried off to be gently cooled to 30 °C under running tap water. The temperature again continued to increase after reaching 35-37 °, and the mixture was again cooled to 30-33 °, and so on for as long as the temperature kept increasing. The reaction mixture was cooled to 15 °, and it becomes more viscous during this time. After dilution with 300ml of cold water, neutralization of sodium bicarbonate was carried out to pH = 6, by the end of the neutralization of the solution became dull, and formed a number of fine-grained sediment. After an exposure of 1 hour the solution was filtered, the precipitate was washed first with water and finally with isopropyl alcohol to facilitate drying. The mass of dry product was 3.5g or about 8% of the theoretical value (assuming the formation of DPT 1 mol to 1 mol DNU). The nature of combustion of the sample did not differ from the standard DPT. The measured melting point temperature of the sample amounted to about 195-198 °C. DPT obtained by the other more traditional method has a melting point of 200-201 °C.


Please let me know if there are errors in my translation.
I do not know russian very good :D

Obviously "Dinitro-pentamethylenetetramine" is just another name for DPT. The site discusses making DPT from sulfamic acid, H2N-SO3H.

[Edited on 18-3-2012 by AndersHoveland]

caterpillar - 18-3-2012 at 15:12

You should read all four pages! (change last digit in link or simple go to another pages of that thread) The best method had number 9. That boy discussed 4 methods of DPT syntesis. His own method gives much better yield than another ones. Your translation is good, but you shouldn't spend time and efforts for translation of the first and not the best experiment. I've translated description of experiment number 9- the best one, that gave yield above 90%. There are some remarcable moments- concentration of HNO3 is crucial. 70% HNO3 gives the best yield, 63% (aseotropic, the usual concentration) is lots worse. 99% is not the best variant too. The most remarkable here is the fact that this method was discovere by an amateur, a kitchen chemist like many people at this forum.

AndersHoveland - 18-3-2012 at 15:33

Experiment 8
The concentration of nitric acid was about 63% (density 1.386g/ml). A mixture of 50 ml of nitric acid and 35 ml of sulfuric acid (92.5% concentration, density 1.825g/ml), which was cooled to 0 °C, was introduced with stirring 25 g of sulfamic acid. The temperature rose to 5 °C. After maintaining the temperature for 20 minutes at 0 °C, 27g of DNU started to be added in small portions with stirring, keeping the temperature below 15 °C. The reaction mixture was then kept at 5-10 °C for 40 minutes, while continuing stirring. The mixture was then gently heated to 30 °C, then heating was stopped, but the temperature continued to increase by itself, as in the previous experiments. Just as before, the temperature was allowed several times to reach 38-42 °C, and at such times the temperature was brought back down to 35 °C by cooling. When heat ceased to occur (in about an hour after heating to 30 °C), the reaction mixture was cooled to 15 °C, while it thickened and became similar to the reaction mixture during cooking. More PETN was diluted 1 to 2 cold porridge, prepared in advance by the freezing of 10% aqueous solution of ammonium nitrate. This was followed by neutralization with sodium bicarbonate to a pH of ~ 6, resulting in much sediment. This was filtered, then washed with water and isopropanol. After drying, the mass of sludge was 14.2g, or 65.1% of theory (DPT 1mol to 1mol DNU). The melting temperature of the product was 194-198 °C.

Experiment 9
The concentration of nitric acid 70% (density 1.411g/ml). All procedures are identical to experiment number 8, but with the following differences: the amount of sulfuric acid is reduced to 20 ml, after the termination of heat the reaction mixture of the porridge thickens much faster and at lower temperature, no more than about 25-30 ° C. The yield of DPT in this experiment was 21 g or 96.3% of the theoretical (assuming the formation of 1mol DPT to 1mol DNU). When doing this experiment two additional times, the yield was 20g and 20.5g, respectively, which was consistently above 90% yield. The products obtained by this method were in the temperature range of 198 ° C.

caterpillar - 18-3-2012 at 17:06

Quote: Originally posted by AndersHoveland  
When heat ceased to occur (in about an hour after heating to 30 °C), the reaction mixture was cooled to 15 °C, while it thickened and became similar to the reaction mixture during cooking. More PETN was diluted 1 to 2 cold porridge, prepared in advance by the freezing of 10% aqueous solution of ammonium nitrate.


With all my respect, small correction of your translation. Aforementioned boy meant, that reaction mixture became like a porridge, that occurs diring PETN cooking. Then this porridge was diluted by half- frosen (mixture of liquid and ice crystalls) 10% solution of NH4NO3. I think, that method, that you described (hexamine dinitrate and sulphuric acide) is good too- it does not require nitric acide at all. Low yield is not a great problem, may be large amout of some by-products.

AndersHoveland - 24-3-2012 at 23:50

Perhaps a perchlorate salt of DPT is possible?

C5H10N6O4*HClO4

Still not great oxygen balance, but it could be easy to make (just react DPT with dilute perchloric acid).

Also to mention, DPT can also be used as a precursor to HMX. If one wants to minimise the ammount of 99% HNO3 or acetic anhydride that needs to be used, the DPT can be made first from normal mixed acids, then nitrated further.
see the other thread in this forum, "HMX by way of nitration of dpt"
https://sciencemadness.org/talk/viewthread.php?tid=738


[Edited on 25-3-2012 by AndersHoveland]

AndersHoveland - 25-3-2012 at 10:25

from E+W forums archive:
Quote:

Ive heard of Dinitropentamethylenetetramine. Is it an explosive? You can make it with HDN and H2SO4. You can convert this to Hexogen but im interestet in DPT itself. Has anyone experiences with it?

HDN [hexamine dinitrate] preparing from book "Lab preparing of nitrocompounds" by Orlova E.Y.:
Dissolve 1 part hexamine in 1.5 parts of water. Then add 50-60% nitric acid (at 15-20C) in quantity sufficient to receive a 20% waste NA.
Filter crystalls and wash it with absolute ethanol. Dry it at 60C.

About DPT:
I think the best way to prepare it is described in US pat 4,338,442. It also possible to make from hexamine and nitrourea with better yeild but I have no details.

DPT has poor stability to hydrolysis. DPT is a intermediate in HMX synthesis.
It possible to make a HMX with 75% yeild from DPT, NA [nitric acid] and ammonium nitrate.


Apparently DPT can be detonated, but has a low sensitivity:
Quote:

Among low sensitivity substances are non—cap explosives: dinitro benzene, dinitropentamethylenetetramine, ANFO, ammonium nitrate, nitromethane, ...

Safety of Reactive Chemicals and Pyrotechnics By Tadao Yoshida, Yūji Wada, Natalie Foster


DPT forms monoclinic [rectangular prism, with parallelogram as its base] crystals.
"The crystal structure of dinitropentamethylenetetramine (DPT)",C. S. Choi and S. Bulusu, Acta Cryst. (1974). B30, 1576-1580

[Edited on 25-3-2012 by AndersHoveland]

caterpillar - 26-3-2012 at 21:10

Quote: Originally posted by AndersHoveland  
Perhaps a perchlorate salt of DPT is possible?

C5H10N6O4*HClO4

Still not great oxygen balance, but it could be easy to make (just react DPT with dilute perchloric acid).

Also to mention, DPT can also be used as a precursor to HMX. If one wants to minimise the ammount of 99% HNO3 or acetic anhydride that needs to be used, the DPT can be made first from normal mixed acids, then nitrated further.
see the other thread in this forum, "HMX by way of nitration of dpt"
https://sciencemadness.org/talk/viewthread.php?tid=738


[Edited on 25-3-2012 by AndersHoveland]


Is DPT a base? May be situation with this compound like one with urea- urea itself is a base and some salts of it are well-known (nitrate), but nitrourea is a weak acide, to say nothing about dinitrourea (thanks, Anders, for pdf about dinitrourea). DPT is a precursor to HMX, and moreover according one russian article nitration of DPT can be performed with HNO3 plus AN without Ac2O. What is most remarkable, this process doesn't require large amount of HNO3- 3.2 mole HNO3 + 1.6 mole of AN per one mole of DPT. Treatment is to be performed at 60-65 C.

AndersHoveland - 27-3-2012 at 00:18

Quote: Originally posted by caterpillar  

Is DPT a base? May be situation with this compound like one with urea- urea itself is a base and some salts of it are well-known (nitrate), but nitrourea is a weak base


DPT contains three tertiary amines (trimethylamine is another example of a tertiary amine). In the molecule of DPT, the nitramine groups will have no effect on the ability of the other amines to act as a base. In other molecules, such as nitroguanidine or 2-nitroaniline, the nitro groups do make the amines less basic because the amines are electron donating to the nitro groups.

This does not mean that all three amines will be able to act as a base. The amines are all in close proximity to eachother, so probably only one of them will be able to hold a positive charge when it is protonated, possibly two, but I think this would be more doubtful. Hexamine, for example, can only act as a base towards two hydrogen ions. (you might have read about many metal atoms holding double or triple positive charges, but other factors are involved, usually complexation with water molecules or crystal lattice energies)

[Edited on 27-3-2012 by AndersHoveland]