RDX production - interesting details

[BLASTER]

I was found this in some swedish file. Hope this not be published here to this time, but I think it's interesting. First is table of yield dependency on reaction time and HNO3 concentration and second is preparation of RDX from HMTD (somebody asked for this?) In original file are also detailed step-by-step procedure for E and KA process. Original file at http://www.flashback.se/arkiv/98/2/PYROKEM.TXT I would be happy if someone can translate details from swedish to english.

Reaktionen lyder:

(CH2)6N4 + 4HNO3 ---> (CH2.N.NO2)3 + 3CH2O + NH4NO3

HMTA salpetersyra RDX Formaldehyd ammoniumnitrat.

Tabellen nedan visar samband mellan nitreringstid, utbyte och
salpetersyrans styrka:

+--------+----------------------------------+
| Tid | Koncentration på HNO3: |
| (min) | 99% | 96% | 93% | 90% | 85% |
+--------+------+------+------+------+------+
| | Utbyte av RDX i % |
+--------+------+------+------+------+------+
| 1,5 | - | 55,7 | - | - | - |
| 2,5 | 66,9 | 68,7 | 40,9 | 13,3 | - |
| 6,5 | 70,2 | 75,3 | 65,8 | 30,5 | - |
| 12,0 | 74,6 | 74,7 | 73,4 | 45,4 | - |
| 24,0 | 80,9 | 79,2 | 77,2 | 59,9 | 14,9 |
| 50,0 | 80,5 | - | - | - | 26,2 |
| 100,0 | - | - | - | - | 33,0 |
| 120,0 | - | - | - | - | 32,6 |
+--------+------+------+------+------+------+

*text formatting in table little fucked*

D. Framställning av RDX från HMTD, salptersyra och ammoniumnitrat.

Som kuriosa skall jag också nämna en helt oanvändbar metod att framställa
RDX ur HMTD (se separat artikel). Utbytet blir lågt (25%) och den
rekommenderas inte.

Tillverkingsprocedur:

1. Blanda ytterst försiktigt 2.5g HMTD med 4.2g ammoniumnitrat. Betänk att
HMTDt antagligen blir kraftigare när ammoniumnitrat är närvarande!

2. I en E-kolv blandas 3.5g ammoniumnitrat med 25g salpetersyra (d. 1.50).

3. Tillsätt sakta HMTD/NH4NO3 blandningen till HNO3/NH4NO3 lösningen.
Temperaturen skall ej överstiga 40øC så ett kallvattenbad får användas.

4. När alla reaktanter är tillsatta upphettas lösningen till 80øC och får
sedan kallna och stå över natten. RDX kristalliserar ut. Filtrera av och
tvätta med vatten.

5. Lös upp RDXet i minsta möjliga mängd kokande aceton och slå ut detta i
100 ml natriumbikarbonatlösning (5-10%). Filtrera igen och torka.

[This message has been edited by BLASTER (edited August 18, 2001).]

[rikkitikkitavi]

Ok here is a quick n dirty translation.
/rickard (yes I am Swedish)


Reaction as followed

(CH2)6N4+4HNO3--->(CH2.N.NO2)3+3CH2O + NH4NO3
HMTA Nitricacid RDX Formaldehyd ammoniumnitrat.

The table below shows the relation between
time of nitration,yield and the concentration of nitric acid
+--------+----------------------------------+
| Time | Conentration of HNO3: |
| (min) | 99% | 96% | 93% | 90% | 85% |
+--------+------+------+------+------+------+
| | yield of RDX in % |
+--------+------+------+------+------+------+
| 1,5 | - | 55,7 | - | - | - |
| 2,5 | 66,9 | 68,7 | 40,9 | 13,3 | - |
| 6,5 | 70,2 | 75,3 | 65,8 | 30,5 | - |
| 12,0 | 74,6 | 74,7 | 73,4 | 45,4 | - |
| 24,0 | 80,9 | 79,2 | 77,2 | 59,9 | 14,9 |
| 50,0 | 80,5 | - | - | - | 26,2 |
| 100,0 | - | - | - | - | 33,0 |
| 120,0 | - | - | - | - | 32,6 |
+--------+------+------+------+------+------+

*text formatting in table little fucked*
(I adjusted the table )


D. Making RDX from HMTD,nitric acid and ammoniumnitrate


As a extra I will also mention a completely unusefSul method on how to make RDX from HMTD (Yield is low, 25 % and I cant recommend it)

Procedure:

1. Mix very carefully 2.5 g HMTD with 4.2g ammoniumnitrate. Consider that HMTD probably will be more powerful when mixed NH4NO3 is present

2. Mix 3.5 g NH4NO3 with 25 g nitric acid (density 1.50)

3. slowly add the HMTD/NH4NO3 mix to the HNO3/NH4NO3 solution Temperature mustnt rise above 40 C ,cool the reaction mixture.

4. When all the reactants has been added , heat the solution to 80 C. Let it cool and stand overnight. Filter out the RDX crystals formed and wash them with water.

5. Dissolve the RDX in the smallest amount of acetone possible and pour it into 100 ml sodiumcarbonate solution (5-10 %). Again filter and dry.

[Mr Cool]

I don't like the idea of mixing an organic peroxide and a strong acid! Also, yield to make HMTD from (CH2)6N4 is low, so I'd just start with (CH2)6N4, HNO3 and NH4NO3. But still, it's quite interesting to know that it works.
If you add an extra two moles of NH4NO3 to the reaction, it will react with the formaldehyde produced to make (in theory) another mole of RDX, so theoretically it'll double your yield. It won't in practise, but it will improve it considerably.
Hmm... it works with 85%? Didn't know that. 33% yield isn't really too bad either. Not as good as 80%, but I'd be happy with it.

Oh, and for those of you that read about my plan to make RDX with Ca(NO3)2 and H2SO4, in the hope that all the SO4-- ions would be precipitated as CaSO4, well it didn't work. A tiny amount of precipitate was obtained, which could be RDX, but there was too little to test! I think maybe the Ca(NO3)2 wasn't dry enough too.

[rikkitikkitavi]

mr cool
In concentrated sulfuric acid there is hardly any SO4- to perciptate Ca(SO4)2 http://theforum.virtualave.net/ubb/smilies/frown.gif Any SO4- will immediately react with H2SO4
H2SO4+ SO4- => 2 HSO4- since H2SO4 is a very very strong acid and when almost waterfree
SO4 ions acts as a base


To dry Ca(NO3)2 completely you need to heat it up to at least 200 C , it will start to decompose at about 400 C but can be melted (561C) before vigouros decomposition takes place.

/rickard

[Lagen]

You are right, rikkitikkitavi (sp?) and you are the second person only I know to point out this fact (first on this forum). It is not very well known, that CaSO4 DISSOLVES in very concentrated H2SO4. Therefore I always emphasize that only DILUTE HNO3 can be made by Ca(NO3)2+H2SO4 (there are a few other reasons for this, too).

------------------
REST IN PIECES

[Lagen]

rikkitikkitavi: Now I can see you've got a few mistakes there in the charges but I can see what you mean.
Mr Cool: I think the main reason why your method failed is that secondary nitramines like RDX are incompatible with H2SO4. For several reasons, making pure HNO3 free of H2SO4 by the above method is impossible. You could try a similar procedure with acetic anhydride but I guess that's what you wished to avoid.

[nbk2000]

One could always make a solution of calcium nitrate, titrate with H2SO4 till all calcium sulphate is precipited, filter, then heat to constant boiling point.

I forget the exact specific gravity of cbp nitric acid, but it's fairly high like 70%+. From there redistilling from sulphuric or using additional H2SO4 in your nitration mix will get the job done.

------------------
"The knowledge that they fear is a weapon to be used against them"

Go here (http://members.nbci.com/angelo_444/dload.html) to download the NBK2000 website PDF.

Go here (http://briefcase.yahoo.com/nbk2k) to download the NBK2000 videos.

[Lagen]

NBK2000, that's a possible method of making HNO3 from Ca(NO3)2+H2SO4 with distillation, but I was talking about the process someone suggested to make 98%+ HNO3 by adding boiled down H2SO4 to Ca(NO3)2 without distillation. I think that's what Mr Cool wanted to do in his method to "simulate" the anhydrous HNO3 in the N-nitration process.

[Mr Cool]

Yeah, that's what I was trying to do. Pitty it didn't work, it would've been so much easier.
IIRC cbp HNO3 has a conc. of 69.5%.

Edit: yes, I am aware that H2SO4 is incompatible with many amines/nitramines. I was just hoping there wouldn't be any!

[This message has been edited by Mr Cool (edited August 21, 2001).]

[nbk2000]

I'm aware of what Mr. Cool was trying to do, and even though direct HNO3 synthesis of the desired concentration may not be possible, it's certainly easier to mix two solutions together, then do one distillation, to get the concentrated HNO3, than to have to do 2 distillations, one to get the dilute HNO3, then another to concentrate it to 99%.

------------------
"The knowledge that they fear is a weapon to be used against them"

Go here (http://members.nbci.com/angelo_444/dload.html) to download the NBK2000 website PDF.

Go here (http://briefcase.yahoo.com/nbk2k) to download the NBK2000 videos.

[lucifer]

I made some rdx with some HNO3 I just made with my distil equipment.
I used 25 gr methenamine and 110 ml HNO3
Slowly added the 25gr to the HNO3, which went quite easy keeping the temperature under 30degr C
After that I put the solution in a water bad of 60 degr C letting the temperature of the solution rise to 55 degr C Keeping it at this temperature for 5 minutes.
Then cooling it down in a ice bad to 20 degr C
During this phase some rdx was becoming visible in the solution.
I let it stand for 15 min.
Then adding the solution to 400 ml of ice water
A lot more of rdx precipitatet out of the solution.
I let this solution stand for 5 minutes
After filtering I neutralised the rdx with 400 ml 5% sodium bicarbonate solution.

The yeild after completely drying was 24 gr which is if I am ride about 60%

Second batch: this time I kept the solution at 55 degr C. for 12 minutes and after cooling it down to 20 degr. C
I let it stand for 10 minutes.

The yeild after completely drying was this time 29.7 gr which would be 74%
So a longer nitrating time at 55 degr C will give a better yeild.

See also <a href="http://www.flashback.se/arkiv/98/2/PYROKEM.TXT" target="_blank">http://www.flashback.se/arkiv/98/2/PYROKEM.TXT</a>

The HNO3 I made was distilled with 400 ml 98% H2SO4 and 350 ml 65% HNO3.
The HNO3 was distilled in a 1L flask , and a vigreux kolom, the vacuum pressure in the system was ~ 0,5 bar.
I collected the first 140 ml of HNO3 that was distilled.
The liquid was almost colourless, only a taint off yellowish was visible.
So assume the HNO3 is almost free of NO.
The density of the HNO3 was 1.504 g/ml so this should be about around 97%, but i cant be exactly sure about this because my scale has a tolerance of ~0.1%.

I also want to reuse the now diluted nitric acid, which also contains formaldehyde, NH4NO3? and ???

Is there any danger from explosion if I would distil this mix to concentrate the HNO3 to 65% and to get rid of the formaldehyde and later distil it with H2SO4, from maybe small amounts of rdx left in the solution? (although I did filter it of course)

[simply RED]

Do not reuse HNO3 from RDX making. In the commerical process they never reuse it, it contains nitraminic impurities, that's why it it converted to fertilizers and never used again as HNO3.