DFliyerz
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Nitric Acid Tip
I just wanted to post something in here about a tip for making nitric acid, because I recently experienced an issue with this. If you want to make
nitric acid with sodium/potassium nitrate and concentrated sulfuric acid, be sure to add enough water. I recently did this for probably the fourth
time but added less water than usual, and by the second distillation I ended up with white fuming nitric acid! It fumed very heavily in air and
ignited on contact with nitrile gloves, so not something I really wanted to deal with. I hope that this information is helpful to anyone planning to
make nitric acid.
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Upsilon
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Yep, always go for the 68% azeotrope. It will make your life much easier. There are very few applications where fuming nitric acid is needed and 68%
won't work.
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TheAlchemistPirate
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I don't mean to sound abrasive but I don't know why you would condemn the use of WFNA simply because it corrodes nitrile gloves... Why not just use
rubber ones when handling it? Did you vacuum distill it or do it under normal pressure?
"Is this even science anymore?!"
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BromicAcid
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Really... that's hardly the worst that could happen. Too much sulfuric acid and you make loads and loads of nitrogen dioxide on heating, believe
me... that is much worse. I speak from experience and I am surprised you ended up with something colorless.
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hissingnoise
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| Quote: | | There are very few applications where fuming nitric acid is needed and 68% won't work. |
Likewise, there are very few EM syntheses where 68% will work . . . ?
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Bert
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Quote: Originally posted by hissingnoise  | | Quote: | | There are very few applications where fuming nitric acid is needed and 68% won't work. |
Likewise, there are very few EM syntheses where 68% will work . . . ?
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Works quite well for making PETN, and is the classic choice for Mercury fulminate.
Good choice for lower nitrated toluenes, napthalenes & similar used as fuels in higher performance AN and chlorate based mixtures and in low
freezing dynamites.
But I'd rather just save the "heads and tails" from making the strongest nitric I can for such uses... They both have their place in a lab.
(I wonder what became of "Boomer" on roguesci? He was good, and very practical & down to earth)
| Quote: |
(By Boomer the dog, via roguesci)
Verified efficient method of preparing PETN from diluted HNO3
use
32,7 ml of 70% HNO3 (75% excess)
18,9 ml of 96% H2SO4
10,0 g of Pentaerythrite
------------------------
or
34,0 ml of 65% HNO3 (66% excess)
24,8 ml of 96% H2SO4
10,0 g of Pentaerythrite
------------------------
or
34,8 ml of 58% HNO3 (48% excess)
36,3 ml of 96% H2SO4
10,0 g of Pentaerythrite
------------------------
Nitration:
1. Cool nitration mixture during mixing of acids, thus minimalize even minimal decomposition of HNO3. Nitration mixture must be cooled before
nitration process to temperature of 10°C.
2. While stiring, add pentaerythritee in small portions (1-2g) to nitration mixture, always after previous batch is dissolved. Nitration mixture
gradually thicken as PETN forming in solution.
3. Constantly monitor reaction temperature and maintain it in 10-15°C range. Interval of adding pentaerytritol conform to reaction temperature, must
not rise over 15°C, leave beaker in cold water.
4. Stir with mixture for next 5 minutes after all pentaerythrite is added and dissolved. Mixture is now thick, but stirring is going well. During
nitration process must not be developed any brown fumes of NOx!
5. Now put beaker with mixture into water bath and maintain temperature at 50°C, continuously stir with mixture. During 20 minutes at this
temperature, all of possible sulfoesters come into PETN for maximal yield of nitration.
6. While maintaining mixture at higher temperature, mixture must be monitored for developing of NOx fumes. Only light brown colour can be in shrouded
beaker. Raised development of NOx pointing to higher temperatures used (even during previous nitration) or insufficient chmemicals purity and further
heating may end up in uncontrolled reaction and oxidation of formed PETN. In this case it is better to do not heat at all and end just after nitration
(if brown fumes apperas during nitration), the yield will be lower. In case of accidentally runaway reaction during heating, immedialtely pour mixture
into cold water, don't try stop reaction by cooling beaker, it will not help.
7. When heating after 20 minutes pass off, pour reaction mixture into cold water and follow standart procedure of filtration, neutralization and
purifying of PETN.
Yield was 22,1g of PETN from 10g of pentaerythrite, ~95% of theoretical yield (with 65% HNO3 used).
This procedure is result of my research of most effective method preparing PETN from diluted HNO3. Acid ratios are precisely calculated on data from
PETN nitration graph published by T. Urbanski in his book vol. IV. Generaly said, PETN is forming to maximum 30% of water portion in nitration
mixture. But, when also H2SO4 is contained in nitration mixture, minimum ammount of water must be keep, or oxidation with small yields occur. With
this acid ratios 20% of H2O is minimum. So, this nitration mixture has 20% of water on nitration start and 30% at the end, area for most effective
nitration, but again only with this ratios. For other acid ratios must be all recalculated. Excess of HNO3 is used to controll ammount of reaction
water. Only ammount of nitration mixture can be extended for lower mixture thickness, but it lower utilization of acids and overall efficiency. But it
isn't necessary.
I hope there is no major mistakes in my translation to english ;-)
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[Edited on 2-11-2015 by Bert]
[Edited on 2-11-2015 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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Texium
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| Quote: Originally posted by hissingnoise | | Quote: | | There are very few applications where fuming nitric acid is needed and 68% won't work. |
Likewise, there are very few EM syntheses where 68% will work . . . ?
|
Not everyone is interested in EM. I also prefer to distill the azeotrope when making nitric acid for
everyday use. Much less dangerous and easier to handle.
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Darkstar
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Very true. I lost all interest in energetics a long time ago. Not that I had any bad experiences or close calls, or anything. It's just that the
instability and unpredictability of many energetics (particularly primaries) makes me rather uncomfortable these days. It's kind of hard to explain,
but I have this weird phobia of not knowing when something is going to happen that is either sure to happen soon, or at least very likely to happen
soon. Obviously this doesn't apply to silly things like what time a friend is going to arrive that is supposed to be coming over in the next couple of
hours. But things that could potentially harm or kill me, such as a small amount of a primary suddenly detonating and blowing my fingers off while
trying to make or transport a blasting cap, scares the shit out of me. Just the thought of 'what if' scares me sometimes.
I'm not really scared of explosives that are at least relatively stable (like PETN), and I'd have absolutely no problem sleeping with a hundred pounds
of TNT or RDX under by bed. But anytime I'm around a primary, no matter how small of an amount, I'm constantly anticipating premature detonation. And
it's that feeling of an explosion that may or may not come at any second that I can't stand. I'm perfectly okay with knowing that death is inevitable
and that one day I'm going to die; however, there's comfort in not knowing when I'm going to die. It could be today, tomorrow, or it could be
70 years from now. While handling sensitive energetics, on the other hand, it's like I at least now have a pretty good idea of when it might
be. I know you could say the same thing about every time you get into a car, but at least the odds of not dying on any given drive are greatly in your
favor.
How anyone can comfortably handle large amounts of crap like AP or HMTD is beyond me. For instance, that kid from Sweden (Phone was his user name, I
believe) who was killed when some APAN unexpectedly detonated. At one point he even posted a picture where he literally had over a kilo of AP, all in
giant piles, just sitting on his living room floor drying. And there are hundreds more people showing things like that on YouTube. How are they not
scared shitless, especially when they know full well how unpredictable organic peroxides can be? Do they have some kind of mental disorder that
prevents them from experiencing fear, or do they just not care if they die?
Anyway, on an unrelated note, I initially read this thread's title as "Nice Acid Trip" for some reason.
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unionised
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The accidental production of stronger nitric acid than you expected isn't the real story here.
If you don't do the research properly and you get things wrong you get an unexpected outcome.
That's a bad idea.
The moral of the tale is make damned sure you know what you are doing before you do it.
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DistractionGrating
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Heh, me too.
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hissingnoise
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I'll concede you MF, certainly, but adding strong H2SO4 clearly ups the 68% conc. significantly!
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Texium
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Damn it, I wasn't seeing it that way, but now it keeps happening!
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Bert
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I understand. But the jug of azeotropic in the freezer sits there very happily for years on end, without bursting, eating the cap or otherwise coming
out to play uninvited...
Azeotropic nitric acid will not likely make RDX, TNT & etc., but given that concentrated sulfuric acid is relatively cheap and time to distill
white fuming nitric is expensive (or just not available) to me, I find it appropriate for a bit of PETN when a project calls for this.
The WFN PETN synthesis given by Rosco IS very good- From my lab notes, about 5% better yield than this one, running with cheap 65% nitric acid. Users
must decide for themselves if it's worth several extra hours work for that incremental improvement.
http://www.sciencemadness.org/talk/viewthread.php?tid=6151#p...
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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hissingnoise
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| Quote: | | I understand. But the jug of ─ azeotropic in the freezer sits there very happily for years on end, without bursting, eating the cap or otherwise
coming out to play uninvited... |
I can't understand this over cautious approach ─ I have fuming NA in SB bottles in a weather-beaten shed for over 7 yrs without problem or worry!
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ave369
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I never add water and always make fuming nitric acid. Because I'm hardcore.
Smells like ammonia....
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Amos
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Yeah but how are your yields? Many preparations I've heard of that go for anhydrous acid have much lower yields than those prepared by azeotropic
distillation.
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szuko03
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Probably because of the music you listen to 
Chemistry is a natural drive, not an interest.
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hissingnoise
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| Quote: | | I've heard of that go for anhydrous acid have much lower yields than those prepared by azeotropic distillation. |
Yeah, down by 30% for sure . . . 
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hissingnoise
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| Quote: | | Probably because of the music you listen to |
And all the psychedelics ingested?  
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szuko03
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I will stick with the inferences made based on his user name rather then wild speculation
Chemistry is a natural drive, not an interest.
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ave369
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| Quote: Originally posted by Amos |
Yeah but how are your yields? Many preparations I've heard of that go for anhydrous acid have much lower yields than those prepared by azeotropic
distillation. |
Nothing to complain about. Five 20g packages of potassium nitrate give me 50 ml of fuming nitric acid. I only see the NOx in the beginning and in the
end of distillation.
Smells like ammonia....
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