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DubaiAmateurRocketry
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Quote: Originally posted by TheAlchemistPirate  | | Ok, Im now soaking it in a high-power grease remover. I made sure to check this thread before I tried heating it. Also, could someone answer my
question about the efficiency of directly adding cold H2SO4 to KNO3? |
When you have a right amount of moles for the conversion, then theoretically, all KNO3 and H2SO4 will result in K2SO4 and HNO3. The cold H2SO4 does
not matter.
H2SO4 + 2 KNO3 > K2SO4 + 2 HNO3
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Bert
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High powered grease remover? What's that... Sodium hydroxide? Non polar solvent? Carbon tetrachloride (That would be cool! Save me some if it is...)
MSDS is probably on line.
WD-40 would be my first choice of common household chemicals to free a stuck ground glass joint.
If you did manage to get some water inside the joint (you boiled the whole thing!) and then heat the glass above boiling point of water with a torch,
be aware: glass is very strong against compression, but not so good against tension. Like the kind of tension boiling water with no way for steam to
escape makes? KA-CHINK!!!
About the cold Sulfuric acid question? Check your PM's.
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Anatol Rapoport was a Russian-born American mathematical psychologist (1911-2007).
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TheAlchemistPirate
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I used an industrial (supposedly high strength) cleaner called purple power.If this doesn't work I will try WD-40 , but I did notice some of the
crystals were gone after 3 hours. I will keep trying and I wont try to open it with heat.
"Is this even science anymore?!"
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NeonPulse
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Wd40 worked for me. I had a thermometer adapter stuck fast to my condenser. During my 1st HNO3 distillation a joint popped and got some of the nitric
on the joint, I did not use enough grease and just pushing it back on hard the heat made it stick hard.
Heating failed to free it but after trying various solvents the WD40 soaked right in and pop, it was finally free. I later broke the jacket inlet on
it anyway..... You can also buy a separator which works kind of like a vise but I guess if you only have one frozen joint why bother.
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TheAlchemistPirate
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That's what happened to me too, neonpulse. I just put the spray WD-40 on the the flask, I also tried a back massaging vibrator thing. Did you guys use
a more liquid-like WD-40? I have seen several methods here that I have been trying on this site all day https://groups.google.com/forum/#!topic/sci.chem/GF1H4eRwYVc . Maybe I should have more patience...
"Is this even science anymore?!"
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underground
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Wich way has the best yields for making RDX with homemade distilled Nitric Acid and without the use of any dehydrating agents like Ac2O/N2O5 e.t.c ?
Also will NH4NO3 increase the yields, or it is not nessesary if your nitric acid is going to be clear (bubble air through Nitric acid to remove any
dissolved Nitrogen dioxide) ?
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Bert
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You have read the whole RDX thread this question is posted in? Or other materials on other sites? DOCUMENT.
You have seen there are a LOT of different synthesis of this chemical? And you are confused as to which is "best"? By "best", do you mean highest
yield for ammount of strong nitric acid used, or of hexamine? Or purest product? Least equipment needed? Fastest?
Rapopart’s Rules for critical commentary:
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underground
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| Quote: Originally posted by Bert | You have read the whole RDX thread this question is posted in? Or other materials on other sites? DOCUMENT.
You have seen there are a LOT of different synthesis of this chemical? And you are confused as to which is "best"? By "best", do you mean highest
yield for ammount of strong nitric acid used, or of hexamine? Or purest product? Least equipment needed? Fastest?
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Al long as here the Nitric acid is the most difficult chemical to prepare, i mean the highest yields for ammount of strong nitric acid used.
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Bert
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| Quote: Originally posted by underground |
Al long as here the Nitric acid is the most difficult chemical to prepare, i mean the highest yields for ammount of strong nitric acid used.
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OK! That makes your question clear to me.
I know exactly where to find the information. It's right here on sciencemadness.org forum.
A number of others know where it is too.
But you are neglecting to do something.
Something that is written in the site guidelines.
Something that I've said is required as part of a properly asked question. Repeatedly.
I am not going to spoon feed you a "cook book recipe" or a link to something containing these.
I will maintain the site policies and close, delete or move such posts and threads I see whose content is not proper or to site standards. I may give
tips on how one proceeds to research topics to people who are seriously TRYING but ignorant. I will ALLWAYS give safety information if I see something
bad is likely to happen from a post.
But it's up to each person to research a topic and follow site standard form to communicate about it. Not going to behave as a professional?
Professionals won't find you worth spending time over, not for free anyhow.
Rapopart’s Rules for critical commentary:
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3. Mention anything you have learned from your target.
4. Only then are you permitted to say so much as a word of rebuttal or criticism.
Anatol Rapoport was a Russian-born American mathematical psychologist (1911-2007).
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underground
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It has been discussed here by Rosco Bodine that Mg(NO3)2 can be used as a dehydrating reagent, like H2SO4, so i was wondering if anyone have ever tried Mg(NO3)2 as a
substitute of AcO2 for making RDX.
[Edited on 8-4-2014 by underground]
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Dornier 335A
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A quick search revealed this patent: Method for synthetizing cyclotrimethylenetrinitramine employing magnesium-nitrate-assisted direct nitration process
They used 12 times as much 95% HNO3 by mass as hexamine, and the molar ratio of Mg(NO3)2*6H2O to hexamine
was 1 to 2. They ran the nitration at 30°C for an hour and reported slightly better yield than for the traditional procedure.
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roXefeller
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That same thread where underground got the Mg(NO3)2 concept from also has relevant discussion from Rosco (http://www.sciencemadness.org/talk/viewthread.php?tid=4701&a...). Using 12:1 by mass HNO3 to hexamine is wasteful of acid (Rosco thinks it can be
done with 100ml HNO3: 40 g HDN, or ~8.3:1 acid:hexamine by mass). It was discussed that the yield was dependent on final reaction temperature. So it
seems the patent authors increased the HNO3 to compensate for the 30C reaction. BTW that patent just seems odd. Why are they using a hexahydrate to
dehydrate? And why are they writing new patents on a 70 year old process (direct nitration of hexamine from HNO3)? As far as trying Mg(NO3)2 to
dehydrate, go ahead, someone has to put patents to practice. You should probably dehydrate the salt first. But you should keep in mind other
concepts that reduce the acid use, detailed in that RDX thread, such as urea nitrate stabilized decomposition at high temps, and ammonium nitrate
supplementation. And you should read Bachmann's work. He suggests varying cleaving mechanisms of hexamine depending on temperatures and dilutions,
which result in different paths to the nitramine.
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hissingnoise
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| Quote: | | Why are they using a hexahydrate to dehydrate? And why are they writing new patents on a 70 year old process (direct nitration of hexamine from
HNO3)? As far as trying Mg(NO3)2 to dehydrate, go ahead, someone has to put patents to practice. You should probably dehydrate the salt first.
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The anhydrous salt is hydrated by dilute acid and cannot be dehydrated, decomposing to the oxide and NO2 + O2 on heating . . .
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caterpillar
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What about Ca(NO3)2 ? This salt is stable up to few hundreds Celsius and can be dehydrated without problems. And the best way to use smaller amount of
nitric acid is to use hexamine dinitrate instead of hexamine. Moreover, this preparation is not very sensitive to NOx, presenting usually in
concentrated nitric acid. I made RDX twice- few grams only, but quite successfully.
Women are more perilous sometimes, than any hi explosive.
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Bert
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I intend to split off the nitric acid production side trip right about here, and graft it onto a nitric acid thread (or shuffle some of it off to
beginnings, as appropriate). It's going to take me a bit to work that out-
My apologies to all, I should have been more proactive on this earlier. And my thanks to those who have followed the site standards when posting
Keep it on RDX, document sources & concepts and it stays...
It is okay to be ignorant when first arriving and posting. However, you must be willing to make an effort to learn. If you are unable to cite
references in support of an idea or as background to your question, the post belongs in Beginnings. Questions that provide background information and
show effort are more likely to receive good responses. If an existing thread covers the topic you're about to post about, post in that thread instead
of a new one. It makes it easier for members to keep up with topics of interest. You may need to search before posting if you're unsure whether or not
a thread already exists. The search engine is not very powerful and may miss relevant threads, but please make at least a cursory effort.
Rapopart’s Rules for critical commentary:
1. Attempt to re-express your target’s position so clearly, vividly and fairly that your target says: “Thanks, I wish I’d thought of putting it
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3. Mention anything you have learned from your target.
4. Only then are you permitted to say so much as a word of rebuttal or criticism.
Anatol Rapoport was a Russian-born American mathematical psychologist (1911-2007).
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roXefeller
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| Quote: Originally posted by hissingnoise |
The anhydrous salt is hydrated by dilute acid and cannot be dehydrated, decomposing to the oxide and NO2 + O2 on heating . . .
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I can only reference Rosco's post to support the claim that Mg(NO3)2 can be dehydrated.
| Quote: |
If it is wished to make the magnesium monohydrate separately , so as to avoid any consumption of acid in its formation , simply long boiling of MgO
with ammonium nitrate
to a cessation of evolution of ammonia should result in
a solution of Mg(NO3)2 . Heating this to dryness and then
to 330C produces the monohydrate .
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underground
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| Quote: Originally posted by roXefeller |
That same thread where underground got the Mg(NO3)2 concept from also has relevant discussion from Rosco (http://www.sciencemadness.org/talk/viewthread.php?tid=4701&a...). Using 12:1 by mass HNO3 to hexamine is wasteful of acid (Rosco thinks it can be
done with 100ml HNO3: 40 g HDN, or ~8.3:1 acid:hexamine by mass). It was discussed that the yield was dependent on final reaction temperature. So it
seems the patent authors increased the HNO3 to compensate for the 30C reaction. BTW that patent just seems odd. Why are they using a hexahydrate to
dehydrate? And why are they writing new patents on a 70 year old process (direct nitration of hexamine from HNO3)? As far as trying Mg(NO3)2 to
dehydrate, go ahead, someone has to put patents to practice. You should probably dehydrate the salt first. But you should keep in mind other
concepts that reduce the acid use, detailed in that RDX thread, such as urea nitrate stabilized decomposition at high temps, and ammonium nitrate
supplementation. And you should read Bachmann's work. He suggests varying cleaving mechanisms of hexamine depending on temperatures and dilutions,
which result in different paths to the nitramine. |
Yea that is true, it looks like a 70-80% yield of RDX can be achieved only with only 21ml of acid and 7gr of HDN.
Also it looks like Urea nitrate and Ammonium nitrate really does not help at all, and it would be better to not use them, just only HNO3 and HDN
| Quote: Originally posted by Boomer | Update: made another batch of nitric (250ml) and tried the first/last fraction for RDX. This is in colour between WFNA and RFNA, hence I call it WTFNA
(what-the-fuck nitric acid, i.e. I dont care). The *same* batch and bottle had given me 80% instead of 92% yield for MHN, and similar batches
preciously 30-40% only for RDX using the 1:2 ratio. And now comes the surprise:
7g of HDN where treated like above, using 21ml of the 'bad' acid, and letting it react for 20 min at 60 +/2 C. Result was 4.75g or 81%.
So a 1:3 ratio will forgive less-than-perfect nitric. It was dark yellow and had a density of 1.515 at -4C (or was it 0C? See above).
Makes d=1.48 at RT, from memory, is that 90% HNO3 considering the NOx content? |
Also caterpillar that one it sounds really interesting, that one i was thinking also but they said that an equilibrium is going to occur and H2SO4 is
going to be in presence, destroying the RDX. But it looks like with your method it can be done. Maybe with higher temperatures we can drive the
reaction forward and stop the formation of H2SO4
| Quote: Originally posted by caterpillar | | What about Ca(NO3)2 ? This salt is stable up to few hundreds Celsius and can be dehydrated without problems. And the best way to use smaller amount of
nitric acid is to use hexamine dinitrate instead of hexamine. Moreover, this preparation is not very sensitive to NOx, presenting usually in
concentrated nitric acid. I made RDX twice- few grams only, but quite successfully. |
[Edited on 9-4-2014 by underground]
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hissingnoise
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| Quote: | | I can only reference Rosco's post to support the claim that Mg(NO3)2 can be dehydrated. |
| Quote: |
From Wiki;
Since magnesium nitrate has a high affinity for water, heating the hexahydrate does not result in the dehydration of the salt. Instead, magnesium
nitrate hexahydrate decomposes into magnesium oxide, oxygen, and nitrogen oxides.
2 Mg(NO3)2 → 2 MgO + 4 NO2 + O2
The absorption of these nitrogen oxides in water is one possible route to synthesize nitric acid. Although it is inefficient, it does not require the
use of another strong acid.
Anhydrous magnesium nitrate is also used to increase the concentration of nitric acid past its azeotrope of approximately 68% nitric acid and 32%
water. It is also occasionally used as a desiccant. |
The decomp. temp. is given as 330°C!
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DubaiAmateurRocketry
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| Quote: Originally posted by hissingnoise | | Quote: |
Anhydrous magnesium nitrate is also used to increase the concentration of nitric acid past its azeotrope of approximately 68% nitric acid and 32%
water. It is also occasionally used as a desiccant. |
The decomp. temp. is given as 330°C! |
Does that mean you can concentrate nitric acid simply with magnesium nitrate(anhydrous) ?
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hissingnoise
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Yes it does, and it is sometimes used in recovery of spent acids but sulphuric acid is convenient for the amateur in that it's a more potent dehydrant
and may be reconcentrated for further use . . .
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roXefeller
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| Quote: Originally posted by underground |
Also it looks like Urea nitrate and Ammonium nitrate really does not help at all, and it would be better to not use them, just only HNO3 and HDN
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A selection from Bachmann:
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In view of the nitrolysis of hexamine to RDX
(one mole) by nitric acid alone, it might be expected
that if the ammonium nitrate were omitted from
the present reaction mixture at least one mole of
RDX would be formed. This is not the case.
Instead, the reaction takes an entirely different
course to yield the linear trinitramine IV as described
below, and only small amounts of RDX
are produced. The result showed that the ammonium
nitrate serves not only as the source of the
two nitrogen atoms required for the second mole
of RDX but is essential in directing the course of
the nitrolysis to form the first mole of RDX.
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another
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The resultant mixture of RDX
crystals (d. 1.77) and HMX crystals (d. 1.96) was separated
into three fractions by repeated fractional centrifugings in a
mixture (d. 1.81) of trimethylene dibromide and mineral oil.
One fraction consisted of RDX with m.p. 197-200°, which
after two recrystallizations from acetone had m.p. 204-
205' (cor.) and contained 3.0 atom per cent. of N15. Another
fraction was chiefly HMX with m.p. 268-269', which
was raised to 282" (cor.) after two recrystallizations from
acetone; atom per cent. N15 based on total nitrogen, 1.5%.
The recovered ammonium nitrate, which was purified by
recrystallization to constant m.p. 168.5-169.5', contained
3.95 atom per cent. of N15 (original tracer salt had 7.5
atom per cent. of N15, based on the two N atoms).
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Naturally occuring N15 isotope is 0.4%.
And from the Hodgson text:
| Quote: |
The nitrolysis of hexamine is a direct route to the military high explosives 1,3,5-trinitro-
1,3,5-triazacyclohexane (RDX) and 1,3,5,7-tetranitro-13,5,7-tetraazacyclooctane (HMX).1,46
The direct nitrolysis of hexamine with dinitrogen pentoxide in absolute nitric acid provides
RDX in 57% yield.54 RDX prepared by this process is exceptionally pure, but other reagents,
like ammonium nitrate–nitric acid–acetic anhydride, give much higher yields, partly because
they use ammonium nitrate to supplement for ammonium nitrogen deficiency in the reaction.
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another
| Quote: |
An unusual feature of the KA-process is that the reaction is conducted at 60–80 ◦C. Solutions
of nitric acid in acetic anhydride are known to be prone to dangerous ‘fume off’ at temperatures
above ambient. However, a saturated solution of ammonium nitrate in fuming nitric acid can be
added to warmed acetic anhydride without such danger. In fact, these reactions are commonly
conducted at 60–80 ◦C as a matter of safety by preventing a build-up of unreacted starting
material.
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While not fully informative of the high temp reaction, it does lend to a stabilizing aspect.
As far as urea nitrate, I'll have to look in my references further. But you should really be doing that also. You can't depend solely on forum
postings for your experiments. Like the Bible, they are open to misreading/misinterpretation of the author's intended concept. Or a lack of
understanding of the conditions underwhich the author observed. You have to triangulate from multiple sources. You are seeking a truth that isn't
necessarily fully documented.
Attachment: cyclic and linear nitramines.pdf (726kB)
This file has been downloaded 606 times
[Edited on 9-4-2014 by roXefeller]
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NeonPulse
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So i did finally get around to attempting a synthesis of RDX. it was a fairly sucessful attempt yeilding 19.3g dry RDX from 95ml HNO3 and 40g hexamine
dinitrate. ithe acid was incorrectly measured though as i used the wrong measuring beaker (doh!) so i doubt it was the full 100ml. but anyway i did
recrystallize it from acetone and got two nice clean crisp white crops sparkling RDX crystals. leaving the acetone to evaporate, the next night after
work i was surprized to see these rather large crystals in the bottom of the beaker somewhat like broken glass, these were many, many times bigger
than the first crops i got and hardly any of the acetone had evaporated. my question is: firstly are these crystals dangerous? like being prone to
detonate due to internal stresses like some energetics?
i2: is it normal to grow rdx crystalls this size?
how big can they actually get if left to grow?
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Napolean Dynamite
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I wouldn't hammer them trying to break them apart, or grind them up in pestle and mortar. They probably aren't very usable in large crystal form,
redissolve in minimal acetone and then dump this in 10x amount of cold water for fine powdery substance. Other than that I too am curious too know if
large crystals are more sensitive, I would not worry much about handling the larger crystals.
Those crystals are very cool though
[Edited on 19-4-2014 by Napolean Dynamite]
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VladimirLem
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hell yeah 
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Bert
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[Edited on 19-4-2014 by Bert]
Rapopart’s Rules for critical commentary:
1. Attempt to re-express your target’s position so clearly, vividly and fairly that your target says: “Thanks, I wish I’d thought of putting it
that way.”
2. List any points of agreement (especially if they are not matters of general or widespread agreement).
3. Mention anything you have learned from your target.
4. Only then are you permitted to say so much as a word of rebuttal or criticism.
Anatol Rapoport was a Russian-born American mathematical psychologist (1911-2007).
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