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Justin
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How well erythritol nitrates in HNO3/H2SO4?
Hi, so far i have only used KNO3/H2SO4 to nitrate erythritol, with good yields as has most people, but as odd as it seems i can aquire 70%HNO3 for
cheaper and easier than alkali nitrates and i have plenty of it. I've heard that addition of erythritol to HNO3 then add H2SO4 too precipitate the
product. Anyone have much experience using HNO3 too nitrate erythritol?
Also after synthesis of NG or EDGN i want too recover my spent acids after separation of product in a sep funnel, what's the risk of explosion of
residual NG/EGDN in the spent acids during distillation of residual HNO3? Temp would be raised slowly to 80C, then after all HNO3 distillate comes
over heat would be raised to 300C to re-concentrate the H2SO4, i would imagine any residual product would decompose upon slow heating however i would
like some input on the dangers of this. It doesnt sound very safe but it would be nice to recover some of the acids. Thanks everyone.
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quicksilver
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Justin, the acid recovery process is just about where most plant tragedies happen. Even with some seriously well thought out scenarios and equipment
it's a very, very dangerous situation. Utilizing equipment DESIGNED to minimized friction, pressure, heat, and material build up, the situation is NOT
EVER worth the risk.
Many, many years ago (especially during major wars) the idea of a self contained energetic materials plant was never without dire risk. The idea was
dropped (acid recovery) during peace-time due to weighing the risk vs pay-off. Most often the concept was to neutralize the energetic prior to
recovery but this made the time (man hours) not worth the endeavor. To NOT neutralize the energetic prior to recovery is madness.
Weighing cost vs the POTENTIAL for a tragedy; it's NEVER worth the risk for a home chemist. If you were interested in HOW it was attempted during WWII
a great deal can be gleaned from TNT plant production. Investment level was in the tens of millions in 1930's dollars. Today, it would be over the
top. Mostly plants that mfg nitrate fertilizer also mfg explosives but in a separate building.
It would be a neat idea but it's really not worth the risk nor the money invested in specialized equipment. Federoff and Weaver have a bit to say on
how some of it was attempted. But for the average hobbyist, the probability of catastrophe is high enough to make it an unsound endeavor The
specialize equipment alone would be very difficult to find. Many of them would include Teflon to Teflon petcocks not glass to Teflon devices, so right
there you have a tough time finding the right items.
It's almost like a "Fortune-cookie" statement: "It's better to ask & find something unsuitable than to attempt and find misery."
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Justin
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Thanks for your input, i agree it's not worth the danger to recover a bit of spent acids.
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pjig
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I have seen in a few cases that the spent acids can be used on a second or third batch of nitrations. (As in NC). You could probably do the same with
erythritol if the nitrating mix wasn't so thick.
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Justin
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My question was would it be advantageous to use HNO3 in the nitration of erythritol instead of a nitrate salt
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Microtek
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My situation (with HNO3 vs XNO3 availability) is similar to yours, so I can give some input on the reaction: Using 18 ml H2SO4 (96%), 12 ml HNO3 (62%)
and 3 g erythritol, I got a yield of 6.3 g (85 %).
The acids were mixed first, then cooled to ca. 0 C.
The erythritol was ground to a very fine powder and gradually added by sprinkling into the stirred acids, keeping the temperature under 5 C.
Stirring and cooling was maintained for 30 minutes after the end of addition, and the mix was then dumped into 500 ml of rapidly stirred ice water.
Product was then filtered and washed again a few more times before being neutralized with NaHCO3 soln.
Product was then collected, dried, dissolved in ethanol and neutralised in solution by tiny additions of ammonia soln until persistent alkalinity.
Water was then slowly added with constant stirring until all product had precipitated.
Finally the collected product was dried and weighed.
I would suggest using a powerful means of motorised stirring because the reaction mixture gets very viscous toward the end of erythritol addition. I
got away with magnetic stirring using a large stirbar and small reactant volume. Also adding water to the ethanol soln may not be the bes way to
crystallize ETN; it gives quite flaky crystals with low bulk density (but if you intend to melt cast the ETN like I did, then that is not much of an
issue).
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Justin
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Thank you very much microtek, your yeilds are the best I have seen so far, I'll try your synthesis route with the exception of a one hour reaction
time and allowing the temp too come up too RT after the addition
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Chemoxid
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70% conc HNO3 for nitration
well im new in this forums and in HEs chimestry area,
but i tried this yesterday...
powerlabs MHN synthesis employ 35ml 70%conc HNO3 and 65ml H2SO4 (98%) and 1gr of mannitol per 10 ml of acid mix.
honestly my yields werent too high...after several synthesis i tried this.
40ml of HNO3(70%conc.) and 60ml H2SO4 (96% conc) and the same rule of 1gr on mannitol per 10 ml of acid.
then i added crushed NH4NO3 prills to the HNO3 till get a saturated solution, then i added slowly the H2SO4 in an ice bath and proceed with the
synthesis.
the nitration was actually pretty good and yields seemed high, after recrystalization from acetone the MHN yields were higher than my others batches.
im not an expert i know that when the H2SO4 is mixed with HNO3(70%) it will react with the remaining 30% of water. so adding a soluble nitrate salt
should increase somehow the ONO2 ammount in nitration bath.
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quicksilver
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MHN is not that easy to nitrate using 70% HNO3. That's simply a reality. One thing that may help is that when you have achieved a true hexanitrate you
will see needle crystals. That visual que sets you on the path to getting it correctly completed.
Mannitol is much more "finicky" than many other polyols. It really wants high strength HNO3, so it's often much wiser to attempt to find some alkali
metal nitrate than to continue with 70% acid.
However, there MAY be a way it could be done. The triangle graph that is related to the use of 70% acid in relation to PETN might be extrapolated to
mannitol. The smartest thing is to work with a few grams due to the likelihood of getting the particulate well mixed & well exposed to the
nitration acid. That is often why some materials do not scale up well. They need exposure to the acid and a smaller weight of materials allow that
exposure to take place more effectively.
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maxidastier
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I tried nitration of Erythritol with self distilled HNO3 98%.
And I suggest not to le temperatures go up to RT and even MORE Important: Stirring!
I got a perfect run away in my first nitration, because I didn't stir all the time, but only every minute!
The trick, saturating HNO3 with alkali nitrate is interesting, because I won't have to distill HNO3.
But how can it work? Where is the water going to, when adding KNO3 to 53% HNO3?
@Microtek : As far as I know: If you get more than double ETN (3g --> 6,3g) then its strange.
At least not only 85% yield...
Did you test it?
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Microtek
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| Quote: |
@Microtek : As far as I know: If you get more than double ETN (3g --> 6,3g) then its strange.
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Erythritol (C4H10O4) has a mol weight of 122 g. ETN (C4H6N4O12) has a mol weight of 302 g (dropping fractions).
So, quantitative yield from 3 g erythritol would be 3*302/122 = 7.43 g. This means that 6.3 g is 6.3/7.43 = 0.848 = 85 %.
Basic stuff.
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maxidastier
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Ok, sry, I had some other facts in my mind. You're right. Basic stuff. I should have known better.
Well, acutally, I just could'nt believe your yields.
That's totally perfect! 
Do you think, we could upscale it to 9 g Erythritol?
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Microtek
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You probably could scale it up to 9 g without much trouble; A factor 3 is not that much. However, bear in mind that you need sufficient agitation as
well as sufficient cooling, and with viscous reaction mixtures such as this, that can be tricky. I would advice keeping the additions slow and the
temp low (extra slow and extra low).
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Justin
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On one instance i scaled up the ratio microtek provided by 20 times, using 60g ETN and following his exact procedure and got a 78% yeild. I have
repeatedly used it at 10 times his scale with consistant results. So yes i would say it scales quite well. Many thanks too Microtek for his repeatable
ETN synthesis using HNO3
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maxidastier
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Microtek, that's really great. I still cannot believe it, you even don't need high concentrated HNO3 e.g. 98% like for PETN, which is very similar to
yours.
Do you think, 53% would also do the trick? What would be the volume in ml?
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Microtek
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You can make PETN in a similar way to this, fuming nitric isn't required. I just like using WFNA because it is cleaner, and gives a more stable
product (since it is easier to get rid of residual nitric than sulfuric). I have no doubt 53 % HNO3 would work as well, but you would need a higher
proportion of sulfuric to fixate the extra water.
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maxidastier
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I thougth, PETN yields are very bad with diluted nitric acid.
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Microtek
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Only if you use dilute nitric alone. If you prepare a mixed acid consisting of about 20 ml HNO3 (62%) and 14 ml H2SO4 (96%) and add 5 g finely
powdered PE at a temp of 5-10 C, you will get a very decent yield (85-90 % I think, but I don't have the actual yield written down, only the
procedure).
You really must neutralize the product in solution though, as traces of sulfuric acid will remain trapped in the crystals.
Also, it is very important to powder the PE as finely as possible since PETN isn't very soluble in the mixed acid. This means that large particles
will only have a thin surface layer nitrated.
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quicksilver
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Of the material available via the "triangle chart" of percentages of 65-70% HNO3 used as a mixed acid in the nitration of PETN Microtek is right on
the money. If you were to extrapolate that and look at ETN the issue is likely not that more complex. However there are a difference between solid
alcohols in mixed acid nitration. One of the stand-outs is mannitol. It's very difficult to fully nitrate ("hexanitrate") mannitol without either a
solid nitrate-mixed acid or a nearly anhydrous nitric acid.
It's actually a good "money-maker" bet, in that there are some "stand-outs" in nitric esters. Mannitol is also a complex nitration in that it does not
scale up easily. The % of nitric acid must be higher than a simple multiplier of the weights at which (example 6 grams) nitrates fully. The lowest
percentile may be cellulose due to the level of nitrogen available in what could be deemed nitrocellulose (I believe that 11% could still be termed
fully nitrated while 13.x is possible).
Someone, possibly Jacqueline Akhavan published a list of (military & commercial products; non-research-endeavor) the highest & lowest nitrogen
context, the most quickly nitrated (contact via mixed acid or Nitric alone), the most cost effective, the most complex molecule, the longest exposure
during a nitration to form completed product, and the most expensive explosive to manufacture commercially (CL20; I believe). In may be that 13.3%
nitrogen in NC is the most costly in terms of nitric acid in manufacturing.
see: Jacqueline Akhavan "The Chemistry of Explosives - 2001 & [Same Author] papers from Royal Society of Chemistry 1998
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gregxy
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Pentaeurethol is probably easiest to nitrate since each -OH is attached to a CH2
resulting in less steric interference. Longer chain polyols have more CH units which
I would think would be more difficult to nitrate than CH2 or CH3.
Another reason could be that partial nitrates of long chain molecules become
insoluable in the acid mix before nitration is compete.
Someone with more knowledge on nitration kinetics should be able to give
an exact reason.
[Edited on 29-8-2010 by gregxy]
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Microtek
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| Quote: |
Of the material available via the "triangle chart" of percentages of 65-70% HNO3 used as a mixed acid in the nitration of PETN Microtek is right on
the money.
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Indeed, I got the acid composition from experimentation with the little Excel macro that has floated around here. I don't recall who made it, but it
is based on the triangle chart from Urbanski I think. Experimentation with that program also indicated the viability of using just 2.5 ml of
practically anhydrous nitric acid per gram og PE instead of the customary 4 ml. A carefully executed experiment confirmed that a yield of about 97 %
could be obtained with this method.
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Rosco Bodine
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Is this the file you are talking about ? 
Attachment: petn2.xls (180kB)
This file has been downloaded 983 times
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quicksilver
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BINGO!
That .xls chart is very valuable. There are others of the same design. If I remember correctly Roscoe pointed this out several years back.
The actual research on erythritol is very marginal. There are patents and some material wherein Nobel & DuPont had a little tif over ownership.
But actual research is limited. During the time when the USBoM was doing some investigation the erythritol at that time was available from natural
sources and was expensive and time consuming to obtain. The "patent rights" were (IMO) more of a gesture of corporate strength than a serious effort
to work with or investigate the utility of the furnished product. Superficially, mannitol took the Lion's share of the attention.
If I am correct Urbanski used the same "triangle chart" for a variety of materials. It's simplicity & utility make it ideal to determine some
things from a quick visual presentation.
[Edited on 29-8-2010 by quicksilver]
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Rosco Bodine
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Attached is a paper which may be of interest
Nitration of pentaerythritol by HNO3-H2SO4-H2O system
L. T. Eremenko, R. P. Parushkova, M. A. Poryadkova and N. M. Stotskaya
Russian Chemical Bulletin
Volume 19, Number 1, 123-128,
Attachment: Nitration of pentaerythritol by HNO3-H2SO4-H2O system .pdf (1.2MB)
This file has been downloaded 1384 times
[Edited on 30-8-2010 by Rosco Bodine]
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quicksilver
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No stroke, Roscoe has taught me a great deal over the years & would honestly suggest that folks interested in this subject; diligently study the
material offered (in every facet of this board). In addition; throughout the years Microtek had a method of experimentation of utilizing very small
amounts of material (thus the moniker) and that has also proved extremely valuable on many levels. Many folks have some wonderful things to offer.
The only reason I digress is there have been folks around here for years that have used a great deal of creativity that I have tapped into and it
helped a great deal. I continually learn from those around me and am often surprised at the level in which I understand and further this hobby by
keeping an open mind and ear to the creativity & access to others. There are some [few] still contributing here but it seems that many have moved
on toward professional & family commitments, finding less & less time to interact.
I am honestly concerned that this freedom in exchange of ideas & questions may not last beyond too many more years in this area. Many wonderful
things come to an end and this MAY be one of the last opportunities to learn, enjoy, and maintain this hobby.
I don't mean to move so way off topic here but I had been listening to the news (& editorials) and it struck me that our world is getting much
smaller. Many people - who have very different ideas of what should be freely available knowledge, are rapidly becoming more of a controlling voice.
It would be a serous shame that we are the last to be able to freely enjoy such a wealth of collective discussion. -=Soapbox mode off=-
In the text "The Pentaerythriyols", Barlow, Barth, Snow 1958 American Chemical Society, the issue of acids being trapped within the crystals had been
addressed and studied. It appears that NO amount of washing can rid Pentaerythriyol (and perhaps Erythriyol) of excess acid and re-crystallization
(& stabilization) is really the only method for longevity and stability.
However a very unique point was made that nitromethane had been used to preform a re-crystallization with [not only] excellent results but a unique
crystal structure.
There is a possibility that such a technique may lead to a more powerful energetic material. Studies during that time indicate that many if not most
solvents that are used for re-crystallization may have an effect either by alteration or by retention within the crystal. Tests with various solvents
show that slight but recordable changes in energetic properties exist after re-crystallization has been completed.
The text is not specific in recording that acetone results in this level of performance or MEK in that level but the alterations do exist. Trace
levels also appear to exist depending upon the technique utilized. A nitromethane re-crystallization may be a very interesting (albeit expensive)
experiment.
edit:
Please note that pp 57-58 offer a rather wonderful collection of re-crystallization routines that result in pourable crystalline preparations (as
opposed to needles) These same techniques MAY be applicable to other polyol esters. Space & time does not permit me to outline them in depth but
solvents such as amyl acetate & ethylene glycol offer key solvents for granular preparations from previously non-pourable ones (as well as
offering methods of increasing density). Simple substitutions of MEK for acetone also preform alterations in crystal structure.
Those who may be familiar with nitroguanidine have realized that a very useful energetic has been hampered by the very difficult, large and flexible
needles resultant in a very simple synthesis. The alteration of this to a highly dense and pourable material could have substantial applications (if
they are not already used in triple based smokeless powders).
[Edited on 31-8-2010 by quicksilver]
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