madscientist
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Preparation of nitrostarch
I am curious about nitration times. How long will it take to fully nitrate starch at about 0-5 degrees Celcius? Also, how necessary is it to stir it
constantly? I have some other questions about the properties of nitrostarch.
Is it soluable in organic solvents like acetone? I believe it would be, but I would appreciate a confirmation of this prediction.
Just how sensitive to shock is it? I'm afraid I cannot trust Megalomania on sensitivity of various explosives (his site said that potassium picrate
has "low sensitivity" which is preposterous). Will it explode from fuse ignition, or must it be detonated with a detonator? I've heard rumors that it
merely requires flame.
I weep at the sight of flaming acetic anhydride.
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Madog
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have you ever made potassium picrate? probaly not i have made it and it is not shock or friction sensitive (to hammers and grinding)
in my opinion it is realy only good for lighting unconfined (looks cool and makes a cool noise) its realy just a novelty i have yet to confine it to
make it burst the container (it has like no bristancy when used as a LE).
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madscientist
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Hrm, I sure have heard otherwise from reputable sources, such as chemistry books and encyclopedias. They said it was dangerously sensitive.
I weep at the sight of flaming acetic anhydride.
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Polverone
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It is difficult to authoritatively pronounce the sensitivity of home made energetic materials. Quality control is very difficult. Atmospheric
humidity, material humidity, trace contaminants, particle size, etc. may all affect sensitivity to initiation and the vigor of post-initiation action.
If you're concerned about safety (and you should be), it's best to err on the side of caution. On the other hand, it can be a letdown to anticipate a
chest-thumping explosion and have a little fire instead.
Madog, I'm curious how dry your K picrate was. It's not exactly something that I'd dry in an oven, but a few days in a sealed plastic bucket at room
temp with a tray of calcium oxide ought to suck up any moisture nicely. I would expect it to make a respectable low explosive, even though it might
not be terribly sensitive to initiation. If you were trying to use the picrate as an LE and failed, did you ever try making picrate whistle mix with
it (supposed to be pretty violent for a pyro comp)? I'm not exactly *endorsing* this idea, but it might be worth a try if you were disappointed by the
explosive nature of the pure picrate.
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madscientist
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Important information... As one should know, virtually all industrially produced acetone contains benzene, an extremely dangerous carcinogen. That is
the reason I no longer like to make acetone peroxide; I do not like the idea of exposing myself to a carcinogen so dangerous as benzene. A substitute
for using acetone to dissolve nitrostarch is ethyl alcohol (sold as "denatured alcohol", which contains small quantities of very toxic methanol).
I weep at the sight of flaming acetic anhydride.
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Polverone
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I have seen many different brands of acetone (talking paint store grade, never ordered it from a chem supplier) and some containers warn that they
contain small amounts of benzene; others do not. For what it's worth, the cheaper brands seem to have this warning more often. The acetone I currently
have in my lab ("Klean-Strip" brand) does not carry such a warning. It claims "100% acetone" on the side information panel. I don't know if this is
truly purer than cheaper stuff or if the manufacturer is just less upfront about the hazards.
Oh, and here's something interesting: I just found out today that nitrile gloves (which are what I usually use) have very good resistance to most
caustics and solvents, but not to ketones (like acetone). Thought that was interesting. Of course, I've had my bare arms up to the elbows in acetone
before and it didn't bother me... Giving up the production of acetone peroxide because you're worried about trace amounts of benzene seems a little
backwards to me. I think making primary explosives is likely to kill you much sooner than your solvents. It's like giving up motorcycle racing because
you're worried about the exhaust fumes.
Acetone is so useful that I doubt it'll ever disappear from my lab (unless the law takes it away). If you are willing to pay a large premium for safer
solvents, you can get 95% ethanol (no methanol) at liquor stores, under various brand names. I paid nearly $20 for 750 mL of the stuff. I got it for
those rare times when small amounts of methanol might pose problems. Of course, that is tougher if you aren't 21 yet. Also, on the acetone front, you
could try e-mailing different vendors/mfrs until you find one that sells benzene-free acetone. Just say you work with acetone on a regular basis and
you're worried about long-term exposure to benzene, even small amounts.
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Madog
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it may have some water in it (it seems dry but it has only been air dried) i have tried mixing it with KNO3 with no luck when lit unconfined it looks
like a REALY good LE but when confined it won't burst a thin paper tube (but it will crack and shoot the fuse away) the water content may be the
problem
oh my god! i just went into my lab and was able to set it off with a hammer for the first time! jese well i guess it is pretty sensitive(but not that
mutch)
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madscientist
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What the hell is going on? This is very strange. I had my sludgey mixture of nitrostarch and starch ready for harvestation. I had heard that acetone
works well as a nitrostarch solvent. However, my chemistry books recommended using ethyl alcohol as a solvent, so I used some denatured alcohol at
first. I managed to dissolve a good percentage of the nitrostarch / starch mix, and poured the liquid into a filter, leaving the undissolved solids in
the beaker. It started filtering well. Then I decided I would try dissolving the remaining nitrostarch / starch mix with acetone (about one third of
the original amount remained). It seemed to dissolve faster and better at first. I poured it into the filter (about a third of the denatured alcohol
had run through the filter already). The speed of filtering dropped off rapidly. Now, about twenty minutes later, it has completely stopped running
through the filter, even when stirred vigorously for the purpose of moving sediments off of the filter paper. There seems to be nothing out of
solution. What the hell is going on? The only thing that I can think of is that there is some reaction taking place between acetone, ethyl alcohol,
nitrostarch, and starch; but I have no clue what as of yet. Any ideas?
I weep at the sight of flaming acetic anhydride.
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madscientist
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I still managed to get about ten grams of nitrostarch from my attempted nitration of twenty grams of starch. I believe the reason for these terrible
yields is that I had the nitration temperature far too low (one degree
Celcius, it probably should have been more like ten degrees Celcius). Nitrostarch is very stable, when i place a small piece of it on concrete, no
matter how hard I hit it with a rock hammer (believe me, you can hit something HARD with a rock hammer, so hard you can crack or chip sidewalk
concrete) and it simply wouldn't go off. When heated by flame it flashed into a small ball of orange flame. Soon I will attempt to detonate it.
I weep at the sight of flaming acetic anhydride.
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PHILOU Zrealone
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Looks ok to me; filtration via paper filter always goes slower and slower and slower!
For sure the impregnated filter with alcool and aceton is the reason! You should have stick to one solvant!
Or start initially with a mix of the two (althrough, I suspect aceton is a better solvant than ethanol).
The procedure must be caried out this way:
Add to the crude solid HE some aceton or hot ethanol (50°C), until dissolved. Filter (hot in the case of ethanol); add a little pure solvant when it
starts to go slower to wash everything. Then add cold neutral or slightly basic water under stirring until the HE precipitates/cristallises out.
Filter again! This time the HE is purer and contains less impurities (HNO3 included-maybe a little base stil in of course). repeat as much as you want
(yield will decrease but purity will be higher).
PH Z
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PHILOU Zrealone
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Sensitivity of picrate is in most cases higher than picric acid itself (what is about as sensitive as RDX). Only NH4 salt, NH2-NH3 and Na salt are
moderately sensitive, then K salt comes (Na, K, NH2-NH3, NH4) salts are difficult to detonate unconfined!
Other picrates can be extremely sensitive primaries Ca salt comes to mind as being one of the worst!
Shock sensitivity tests with a hammer and a hand hit are very unreliable!
Shock sensitivity is generally expressed as the energy provided by a falling weight (in kg) from a given height (m).
Ex: NG has a sensitivity of 0,2Nm; this means that in 50% of the cases (13 trials on 26!!!) the tiny 1-2mg sample wrapped in Al foil and placed under
a percussion armor and on an iron block will take fire, deflagrate or detonate with a sharp crack under the blow of a falling weight of 0,2N from 1
meter height!
0,2N is equivalent to 0,020387 kg (so approx 0,02kg or 20g!
N is the unit of force expressed in Newtons; typicaly a weight standing on a scale press on it with the gravitational acceleration (g= 9,81 m/s*s) and
thus 1kg has a weight force of 1kg*9,81m/s*s= 9,81 Newtons)
This value is often rounded to 10N/kg!
So NG with its 0,2Nm is quite sensitive since it is the force excerced by the fall of 20g from a meter and by the magical of mathematics and physical
energy conservation:
F(20g/1m) = F(2g/10m)= F(200g/0,1m(10cm)) = F(2kg/0,01m(1cm))
So 20 g falling from 1 meter has the same energy of impact as 2000g (2kg) from 1cm...you easily understand why people are not very hot to carry NG as
a liquid!
Now back to picrates:
Picrates are in that range of sensitivities some are below 0,2Nm some are a little over, but they are solid, while NG is a liquid; when home made test
is made with NG, it splashes all arround-but if you absorb it on toilet paper detonation will occure much easier since it retain the NG wel in the
travel of the hammer!
So basically an idot would say...hey my NG didn't explode when I hurted it with a hammer...he forgot that point and the fact it is possible that under
a given shock, the explosive don't go off (shock sensitivity are made 26 times at a same height with the same weight!); but that next time it
will...as it was the case of our dear Madog!
So as said Polverone: better consider explosives to be as sensitive as NG...your life hangs on it!
PH Z
PH Z (PHILOU Zrealone)
"Physic is all what never works; Chemistry is all what stinks and explodes!"-"Life that deadly disease, sexually transmitted."(W.Allen)
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madscientist
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I have found that the runaway nitration temperature for nitrating starch in concentrated mixed acid is about 46C. If the temperature slides above
that, you're going to have to drown the nitration in water. Trying to bring the temperature back down with an ice bath will work about as well as
trying to extinguish a beaker filled with burning thermite by placing it in an ice bath.
[Edited on 24-6-2002 by madscientist]
I weep at the sight of flaming acetic anhydride.
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PHILOU Zrealone
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Here is to reply to MadScientist question!
(p253- Explosives 4th, revised and extended edition by Josef Köhler /Rudolf Meyer)
Nitrostarch:
(C6H7O2(ONO2)3)n
Pale yellow powder
Empirical formula of the structural unit: C6H7N3O9
Oxygen balance at 12,2% N:-35%
Density: 1,6g/ccm
Maximum value attainable by pressing 1,1g/ccm
lead block test: 356 ccm/10g
Deflagration point: 183°C (361°F)
Impact sensitivity: 1,1 kp m = 11 Nm (1,1kg from a meter)
Unsoluble in water and ether; soluble in ethanol/ether mixes and in aceton.
Nitrostarch with various N contents (12-13,3%) is prepared by nitration of starch with HNO3 or nitrating mixtures.The resulting crude product is
washed in cold water and is then dried at 35-40°C.
It ressembles nitrocellulose in several respects, but owing to its poor stability, difficulty in preparation and hygroscopicity, it is not used
anywhere outside the USA "Headache-free industrial explosives are based on nitrostarch".
Those values are for the 12,2 N contain, not for the 13,3% that will be denser, and display higher sensitivity, and power!
Anyway as I have proved already elsewhere:
Polymers of a monomer display lower or equal sensitivity to shock/heat; higher performances and higher densities.
Thus nitrocellulose being a higher polymer of glucose than starch NC>NS in explosive properties.Also it will be wise to wash the NS with Na2CO3 water
since it is even less stable than NC towards moisture and hydrolysis!
PH Z
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Trotsky
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Does anyone here have much experience with nitrostarch? Specifically I'm interested in it's ability to undergo DDT when confined, or is it like NC
and very difficult to detonate without a primary?
I have an AN/Nitrokerosene mix (about 93:7) that I wish to detonate and I was hoping that NS might undergo DDT easily enough to detonate the ANNK.
The more I read, though, the more I think it's unlikely to work well. I don't want to use peroxides but maybe a .1g of 5050 peroxide-starch blend
atop 1g straight NS atop the ANNK would work well enough?
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Antiswat
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benzene in acetone..
well if you want pure acetone it should be pretty easy... (:
vinegar + CaCO3 > calcium acetate
calcium acetate + ~160*C > acetone + CaCO3 (yes sorry for not giving the full chemical names etc. but you get the idea)
the CaCO3 can then be reused
but i dont really see the actual problem in trace amounts of benzene when handling deadly sensitive primary explosives? i mean you have a decent risk
in your hands already..? (:
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Trotsky
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I don't think that anyone of meaningful intelligence is actually concerned with trace amounts of benzene.
So back to the point of the thread-
Is NS considered a primary, secondary or tertiary explosive? It seems like a secondary to me but I'm not entirely positive.
There's a lot of old patents on it, but not much truly scientific in nature.
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