Sciencemadness Discussion Board

DDNP & related compounds: The über thread!

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Madog - 29-1-2003 at 19:38

DDNP seems like a perfect primary, relitively easy to make for the home chemist and powerful, not too sensitive and most importantly storeable. i tried to maek it myself:

i made around 9g of picramic acid via the method shown in books that you find about primarys( Improvised Primary explosives, KIBC, etc) and then i used the ratios on megas site to make the HNO2 solution, to this i added 5g of picramic acid. the reaction was quick with stirring, and lots of yellow/light brown precipitate was formed, this was filtered and dryed, it burns like described but i tried to confine some with no luck. i tried the procedure again only i disolved 4g of the picramic acid in around 250ml of water, this seems very strange that it disolved, picramic acid is only 0.1g/100ml but sodium picramate is 2g/100ml. i got the same precipitate as last time, acts the same too.

i got about 3 grams both times, i wonder what it is, will explode from shock but takes a nice blow! perhaps i should try confineing it more, i didnt think DDNP would need so much confinement, it is also soluble in water, DDNP is not. the PH of a solution of it was about 6, but im thinking its actualy neutral considering it was made with acid and unwashed.

anyone have any idea what it is? perhaps the "picramic acid" was sodium picramate? the picramic acid was nice red and burned nicely leaveing lots of ash, it didnt burn with a soft flame. the product burns the same only alot faster and leaves less ash.

any ideas?

[Edited on 17-6-2015 by Bert]

Nick F - 30-1-2003 at 10:57

"relitively easy to make for the home chemist"

Haha, [ironic] lol.

Sodium picramate is red, picramic acid is more brown.
You may have a sodium picramate/picrate mixture I guess, probably with a bit of DDNP and other crap. It sounds like the product I normally get, which is not DDNP I think.

The few times that I've had DDNP form, it often forms in small dark reddish brown grains consisting of masses of microscopic crystals, resulting in round grains about 0.5mm accross, which are very convenient as they are free-flowing. I don't know if this is normal.
It burns almost as fast as guncotton, producing a little black mushroom cloud of soot, that hangs in the air like when you burn acetylene without extra oxygen. It also produces radiating soot stains on whatever you set it off on.

Madog - 30-1-2003 at 12:09

ok, hmm, well, it seems easy. next time i make picramic acid im gona try treating it with HCl before filtering. then washing with cold water. picramic acid shouldnt disolve like that. i think your right about my product at least to some extent, it leaves yellow stains like TNP does so im thinking some is TNP or Na picrate. the Na picrate was disolved in manufacture of picramic acid(for the most part) but i did and still do have a couple little rocks of Na picrate in the product.

andreas - 1-2-2003 at 05:49

Has anybody noticed a so2 smeel when burning their endproduct.
It's obiously not ddnp.
As soon as I make my nitrate addition machine I'll make up some tnp to make some ddnp. I have received some commercial nitrite, but is their a other way to reduce the picric acid to picramic.

Madog - 7-2-2003 at 19:42

i have also noticed the SO2 smell

Madog - 26-2-2003 at 12:46

today i set off the stuff i had, i just put it in a pill bottle with a fuse and chucked it in the backyard, made a nice fireballish flash with a report, but that stuff as said before is definately not DDNP, it seemed somewhat as senstive as picric acid to hammer

PHILOU Zrealone - 23-3-2003 at 14:03

DDNP:
Red yellow amorphous powder
Density: 1,63g/ccm
Deflagration point: 180°C
Impact sensitivity: 1,5 Nm (150g from 1 meter or 1,5 kg from 10 cm)!

Sparingly soluble in water!
Soluble in methanol, ethanol!
Very soluble in aceton, nitroglycerin, nitrobenzene, aniline, pyridine and acetic acid!
Darkens fast in sunlight!

Made from picramic acid by diazotation in excess HCl with NaNO2 and efficient cooling!

The dark brown product is then purified by dissolution in hot acetone and reprecipitation with cold water!

Priming abilities:
More powerful than Hg fulminate and a little less than Pb azide!

Some personnal coments:
:( :( :mad: :mad: :( :(

1°)To make picramic acid you need Trinitrophenol; but in TNP synthesis if not strong enought acids are used; you end up with DNP that is also sensitive HE (less sensitive and powerfull than TNP); it also makes sensitive unsoluble explosives heavy metal salts). DNP and TNP looks pretty much the same thus!So if you had DNP; you would make a very poor picramic like compound!

2°)When picramic acid is made you may have reduction of ortho, but also of para nitro from TNP...if no purification is made, you have a mix of picramic acid and of paraamino dinitrophenol that would lead to a diazonium salt of different properties than DDNP!

3°)If you work with an excess of dilluted HCl; the only salt of sodium you will find is NaCl; sodium picramate can't exist in strong acid solution!

4°)If you don't cool enought the reaction media; you will have oxydation and loss of N2 from the diazo compound and you come back to a dinitrophenol or dinitroorthoresorcinol!
(O2N)2C6H2(OH)(N2Cl) -H2O/heat-> (O2N)2C6H2(OH)2 + (O2N)2C6H3-OH + N2 + HCl

5°)If you don't recristallise the crude impure product from aceton, you will have poor HE properties!

Polverone - 28-3-2003 at 12:32

Quote:

From: Anonymous
To: (my e-mail address)
Subject: DDNP and organic nitrites

For those of you who are doing experiments investigating diazodinitrophenol DDNP a different approach to the nitrosation may produce a more desirable product.

The disadvantage of the DDNP end product normally produced from the nitrosation of picramic acid in aqueous solution is that the DDNP precipitates as a low density amorphous powder unless crystallization modifiers and special recrystallization techniques are employed to improve the density of the end product.

It has occured to me that a better crystalline form of DDNP might result directly from the nitrosation if the nitrosation of picramic acid or sodium picramate was performed in alcohol solution and the nitrosation agent is an organic nitrite. In another communication I made reference to ethylene glycol dinitrite. Because of the ease of synthesis and the high boiling point the ethylene glycol dinitrite (b.p. 98 degrees centigrade) is of particular interest as a nitrosation agent. See US2166698. I would avoid the use of isopropyl alcohol as a candidate solvent because DDNP reacts with it. A lower alcohol like methanol may be okay.

After the nitrosation is completed the alcohol could be evaporated or a slow dropwise addition of water could be used to produce a slow precipitation of the DDNP which should have a better crystalline form and higher density by either method.

I have not attempted this approach for DDNP so this only a proposed experiment which seems logical. There is not enough time for me to pursue experiments of my own regarding every idea that occurs to me. So I simply pass along these ideas and welcome any feedback from anyone who may do the experiment.

A s an afterthought related to the gemeral topic of ntrosation organic nitrites may be useful also in producing better yields of R-salt in nonaqueous sytems and R-salt itself may find use a nitrosation agent in some reactions.

DDNP patents

Polverone - 28-3-2003 at 16:30

Quote:

From: Anonymous
To: (my e-mail address)
Subject: DDNP related patents

The extent of my own experiments with DDNP revealed that the amount time and of work required can be applied to produce other different initiators which are superior to DDNP. For any others pursuing further experiments, I can share my list of patents related to DDNP which I have saved from when I was experimenting with DDNP.

US2396152 and GB568109 describes coprecipitation of nitrated polyhydric alcohols/DDNP useful as flame sensitive detonating compositions.

This process would be unaffected by the crystalline form in which the DDNP was obtained from synthesis, since the DDNP is redissolved for producing the coprecipitate. I did not do experiments to confirm the findings described by the patent. These particular patents are listed first because in my estimation they describe the application where DDNP would potentially find any practical usefulness, basically being used as a cookoff enhancer to decrease the critical mass of sensitive secondaries which are known to undergo deflagration to detonation transition in slightly larger quantity all by themselves when ignited in confinement.

The conclusion at which I arrived after many experiments with DDNP is that it is one of those materials which is simply over rated in most of the literature, and easily surpassed by alternate choices in real world performance tests. DDNP is one of those materials which seems to be a darling of technical writers, but simply fails to make as good a showing in actual tests. If one reads all the related patents and follows all the shortcomings of DDNP which are attempted to be addressed by various improvements, the story will become clear that DDNP is really not that great. Otherwise there wouldnt be so many patents which describe ways of trying to improve its density and so forth.

Anyway, the following additional patents are DDNP related:

US1404687 original patent
US1428011 describes DDNP/picric acid eutectic and acknowledges the
decomposition of DDNP by certain solvents.
US1472791 ammonium picramate from picric acid
US1460708 described process seems inherently dangerous
US1952591 DDNP classic synthesis described
US2408059 crystallization modifiers
GB836410 starch modified granulation
GB849101 methylcellulose granulation improver
US2214721 DDNP/chlorate enhanced mixture
US2104513 DDNP/lead nitrate density improved mixture
GB333534 DDNP/lead azide mixture Hehehe Why bother ?
GB333539 DDNP/oxidizer mixtures Not hot enough by itself ?
GB406228 lead dinitrophenylazide from DDNP/ sodium azide/lead nitrate
GB412460 same as above, tried these and they are much inferior to
azo-clathrates so why bother ?

My own experiments with DDNP ended with the conclusion that DDNP basically sucks. And when you need to use a nitrite and picric acid, it is simply a waste of precursors when compared to using the nitrite(with hydrazine) to get to sodium azide, and then the picric acid being used in an azo-clathrate synthesis. With regards to DDNP, been there, done that already. Maybe I missed something in my experiments that others will find. But based upon what I found, I would never recommend DDNP as a worthwhile synthesis.

Taaie-Neuskoek - 30-5-2005 at 06:12

Can picramic acid (1-hydroxy 2-amino 4,6 dinitro benzene) not be made by starting from 2-nitrophenol, reduce the nitrogroup to an amino group and nitrate the 1-hydroxy 2-amino further to picramic acid?

2-nitrophenol is not probably not very easy to make, as the nitrogroup will most likely be introduced at the 4-postion, so separation is needed one or the other way, at a certain stage.
Under which circumstances would the nitration take place, probably boiling in H2SO4 and HNO3 for a while??

Sickman - 25-1-2007 at 00:02

Rosco,

I know you have mentioned in this thread that "DDNP basically sucks" and I would agree with that in the sense that DDNP alone without any measure to make it more "unequivocal" as you would put it, doesn't make a reliable initiator.

However in my reading of several patents on DDNP it has occurred to me that coating the crystals with dextrin for example, creates confinement of the crystals which causes them to be more "unequivocal'. However just like lead azide, dextrinating the material doesn't lead to a superior initiator, as compared to the use of the azo-clathrate, caged lead azide, in US3431156 and your own personal improvement to the patent. Thanks for that by the way!;)

Now bear with me here for a moment while I present my idea! In keeping with the thinking that lead picrate is able to entrap a significant amount of lead azide, I was wondering if lead picrate would not be able to entrap diazodinitrophenol within it's crystal structure in much the same way as it does with lead azide? The goal of course being to make the DDNP entrapped within the crystal cage of lead picrate more "unequivocal", being detonated directly from flame as opposed to doing it's typical deflagration to detonation transition, which in the case of DDNP, won't occur without confinement. My thought here is that the DDNP entrapped within the lead picrate would be confined by the lead picrate, causing an unequivocal effect.:P

Now the technical considerations! In my estimation it's seems theoretically possible for the lead picrate or lead picramate, which ever the case may be, to entrap within it's crystal structure DDNP. However, now I'm trying to come up with a simple method for introducing the DDNP into the lead picrate structure. At the same time it seems to me that I cannot assume that the lead picrate will respond the same way to DDNP as it does to the azide.

One possible senario that doesn't really click very well by my reasoning, but may be worth a try, is to go for entrapping the DDNP in lead picramate as opposed to lead picrate. The method I was thinking was to first prepare the lead picramate by adding picramic acid to an acoholic sodium hydroxide solution and then adding lead nitrate to this. Then bubbling nitrous oxide through the mixture. However I see potential flaws in this approach, becase it expects that the nitrous oxide will convert a large portion of the lead picramate to DDNP and simultaneously entrapping the DDNP, into a forming clathrate of DDNP, with the unreacted lead picramate.

Any suggestion for the entrapment of DDNP in a true clathrate with lead picrate or lead picramate or some other energetic material that like those afformentioned have the ability to self deflagrate(for sure) and also the ability to be a crystal host to DDNP (maybe) , would be most appreciated!:o

Sickman

Rosco Bodine - 25-1-2007 at 01:03

If it had any chance of working it would have to be run in a solvent other than plain water , something like a moist acetone or alcohol or toluene ......and the DDNP would
probably have to added already formed into the hot solution .....no isopropanol because that reacts with DDNP . But I am not sure this would even work since
the basic lead picrate clathrate structure is based on
a commonality of all components being lead salts which
have a strong tendency to also form double salts .
I am not sure that a non-lead compound would have much hope of merging into that matrix , since it would be
a dissimilar material .

DDNP has a hydrazine derivative and salt that could be more interesting . And the disclosure of methods for slow precipitation and crystallization of DDNP in denser
form advanced its potential beyond that of the low density material on which I based my observations that
it wasn't very impressive . I think DDNP is probably
useful under very specific qualified conditions where it
is optimized ....but there are easier things to get right
so that they perform predictably well .

Lately I have been looking at some of the polysulfide
patent literature related to production of picramic acid
in order to refine synthesis of that precursor . Pinnning
down good details on that should greatly facilitate any
further experiments with DDNP by making it easy to produce in good quality crystals in good yield .

I think it warrants further experiments but the usefulness
in a clathrate doesn't seem as promising as some of the other possibilities . The clathrates usefulness is really
pretty specific as a means of enhancing the chemical stability of lead azide . But it is the exceptional power
and detonability of lead azide even in that "diluted"
form where it is bound up in a clathrate which lends
the not greatly diminished small quantity detonating
property to the clathrate . DDNP isn't hot enough and sassy enough in small amounts to do for the clathrate
what lead azide does . That's my opinion on it anyway .

braden00 - 10-5-2011 at 17:57

Ok I cut apart a bunch of #11 percussion caps which are used in guns...ive tried using google but i cant find out the compound in them. I think its ddnp because that seems like the obvious choice as they are non-toxic which rules out lead and mercury compounds. The powder in them is a dark brown/greenish powder and is pretty sensitive to a hammer blow. Its also seems to be very powerful any idea as to whats inside?

quicksilver - 11-5-2011 at 06:16

Quote: Originally posted by braden00  
Ok I cut apart a bunch of #11 percussion caps which are used in guns...ive tried using google but i cant find out the compound in them. I think its ddnp because that seems like the obvious choice as they are non-toxic which rules out lead and mercury compounds. The powder in them is a dark brown/greenish powder and is pretty sensitive to a hammer blow. Its also seems to be very powerful any idea as to whats inside?



The commercial brand name would have to be researched if a lab was not available to utilize a variety of tests. Most often the formula is a trade secret and NOT publicly available. "non-toxic" is a very unusual descriptor. I don't believe I can think of any explosive material that is "non-toxic". But the possibility of it being DDNP due to it's color is low. Color really doesn't mean that much with many commercial products as their may be another reason such as binder - for it's color, etc, etc.
It could be tetrazene and tetrazene-combinations. There really is no way to know outside of testing the material.

The WiZard is In - 11-5-2011 at 10:45

Quote: Originally posted by braden00  
Ok I cut apart a bunch of #11 percussion caps which are used in guns...ive tried using google but i cant find out the compound in them. I think its ddnp because that seems like the obvious choice as they are non-toxic which rules out lead and mercury compounds. The powder in them is a dark brown/greenish powder and is pretty sensitive to a hammer blow. Its also seems to be very powerful any idea as to whats inside?

You checked for an MSDS?

braden00 - 12-5-2011 at 18:17

I haven't checked but I did test solubility and it was insoluble in water but soluble in acetone which is in line with the behavior of DDNP. also its friction sensitivity is pretty high once I put it in water and filtered the impurities...I guess theres no way to know for sure just an interesting though

Percussion cap MSDS

The WiZard is In - 12-5-2011 at 23:47

http://www.chemcas.com/msds112/cas/3955/15245-44-0_109-27-3_...

Blount Inc.

http://glarp.atk.com/2008/msds/Musket_Caps.pdf

CCI

CCI only claims that their #11's use an — Modern non-corrosive, non-mercuric priming mix

http://www.cci-ammunition.com/products/primers/primers.aspx?...

Remington MSDS

http://www.spreadia.com/Percussion_caps/133494963/Remington_...

-----------
&c., &c. Google is your friend.

www.justfuckinggoogleit.com



The WiZard is In - 13-5-2011 at 00:07

Quote: Originally posted by Madog  
DDNP seems like a perfect primary, relitively easy to make for the home chemist and powerful, not too sensitive and most importantly storeable. i tried to maek it myself:


Good old Köhler and Meyer 4ed. of which I own a hard copy
(I have an PDF of a latter ed.) cites —

Title: Diazophenols - Their Structure and Explosive Properties
Personal Author: Lowe-Ma, Charlotte K Nissan, Robin A Wilson, William S
Corporate Author: NAVAL WEAPONS CENTER CHINA LAKE CA
Source Code: 403019
Page Count: 33 page(s)
AD Number: ADA197439

A free DL from the usual source.

By da. K&M claim that D.D.N.P. which is a
red amorphous
powder
is It is of interest for --> Lead-free priiming
Compositions.


Humm a red powder in a Green comp. Chemistry
is funny that way sometimes.

[Edited on 13-5-2011 by The WiZard is In]

KemiRockarFett - 27-7-2011 at 14:09

Just want to add something about DDNP. I tried the synth long time ago and can say it was not easy.

The terrorist in Norway claimed that he used DDNP as primary in his bombs. Its written in his manifesto. He also writes that diesel fuel is an oxidant :) How many here belive that a man with no chemistry knowledge manage to synthesise this primary explosive?


AndersHoveland - 27-7-2011 at 14:51

Quote: Originally posted by Taaie-Neuskoek  
Can picramic acid (1-hydroxy 2-amino 4,6 dinitro benzene) not be made by starting from 2-nitrophenol, reduce the nitrogroup to an amino group and nitrate the 1-hydroxy 2-amino further to picramic acid?

2-nitrophenol is not probably not very easy to make, as the nitrogroup will most likely be introduced at the 4-postion, so separation is needed one or the other way, at a certain stage.
Under which circumstances would the nitration take place, probably boiling in H2SO4 and HNO3 for a while??


Nitration of 2-aminophenol would put the initial nitro group in the 3- position. Further nitration would probably result in 2-amino-3,5-dinitro-phenol. Note that such products cannot be readily diazotized, since the amino group is in a position where it is electron-donating to the nitro groups.
For example, 3-nitroanaline can be diazotized with nitrous acid, but not 2- or 4-nitroanaline. And for this same reason, nitration of analine does not result in 3-nitroanaline.

Nitration with mixed acids on phenol produces about five times as much 2-nitrophenol than 4-nitrophenol.
pure 2-nitrophenol melts at 45degC, whereas 4-nitrophenol melts at 114degC. The two isomers can be separated by steam distillation. Rather, it is 3-nitrophenol that would be very difficult to prepare.

Nitration can be done at room temperature, with mixed acids.
Another bit of information to throw in: benzene is not nitrated by mixed acids at room temperature, but must be heated to boiling, Interestingly, nitrobenzene can be obtained from the reaction of benzene being boiled with only 65% concentrated nitric acid for about one hour (reaction is faster if higher acid concentrations are used). The product even shows the presence of a lesser quantity of 2,4-dinitrobenzene, which becomes somewhat more prevelent after 90 minutes. (I read about this in another forum where a chemistry teacher expressed surprise that the nitration could be done with such a low concentration of acid)

[Edited on 27-7-2011 by AndersHoveland]

PHILOU Zrealone - 28-7-2011 at 05:46

Quote: Originally posted by AndersHoveland  

For example, 3-nitroanaline can be diazotized with nitrous acid, but not 2- or 4-nitroanaline. And for this same reason, nitration of analine does not result in 3-nitroanaline.

Stil 2-nitrobenzene diazonium perchlorate, 4-nitrobenzene diazonium perchlorate and 2,4-dinitrodiazonium perchlorate do exist...
Also mixed acid nitration of aniline leads mostly to 3-nitroaniline because of the protonation of the amine...to get ortho or para nitroaniline, one needs to protect the aminogroup from protonation via acetylation for example.

Quote: Originally posted by AndersHoveland  

Nitration can be done at room temperature, with mixed acids.
Another bit of information to throw in: benzene is not nitrated by mixed acids at room temperature, but must be heated to boiling, Interestingly, nitrobenzene can be obtained from the reaction of benzene being boiled with only 65% concentrated nitric acid for about one hour (reaction is faster if higher acid concentrations are used). The product even shows the presence of a lesser quantity of 2,4-dinitrobenzene, which becomes somewhat more prevelent after 90 minutes. (I read about this in another forum where a chemistry teacher expressed surprise that the nitration could be done with such a low concentration of acid)

I have also noticed that paradox...when all organic chemistry books mention the need to use concentrated HNO3 or mixed HNO3/H2SO4 to allow nitration of aromatic hydrocarbon.
I have experimentally found that when toluen is subjected to HNO3 (69%) thus with a lot of water, in a closed vessel...it is only a matter of second before a noticeable yellow colouration occurs at the interface of the toluen layer (on top) and of the nitric water (bottom phase)...this fast turns into orange and then brown colour (after a few days).
I have taken pictures of that mix now and then initially after hours, then after days, then after monthes...the toluen very soon turns orange, brown, dark brown...then after a month at ambiant T° (+/- 20°C) thus without any heat or mixing...all the toluen becomes a yellow-orange pale solid...
Following what I have noticed with friends (via solubilisation in NaOH, Na2CO3, and melting points)...it seems to be paranitrobenzoic acid...but I still have to verify if orthonitrobenzoic acid is absent...it seems very little ortho and paranitrotoluen are also present in the mix...
This is thus a one pot synthesis or paranitrobenzoic acid!:cool: Yields remains to be confirmed.

[Edited on 28-7-2011 by PHILOU Zrealone]

AndersHoveland - 28-7-2011 at 08:40

Nitration of analine with the usual mixture of concentrated nitric/sulfuric acids is very problematic, because of both charring, and oxidation of the analine to nitrobenzene
(using a large excess of sulfuric acid helps minimize formation of nitrobenzene). It is true, however, that low yields of 3-nitroanaline (without significant formation of other isomers) can be obtained, however. Even the use of 60% nitric acid can result in some charring of analine, and this can be partially reduced by cooling the nitration bath. With 75% concentrated nitric acid added to excess analine, charring takes place fairly quickly.

Adding an acetyl group to the analine, using acetic anhydride, before nitration will make the reaction run much smoother without the byproducts, the acetyl group later being hydrolyzed off with a mildly strong base, but in this case mostly 4-nitroanaline is produced, with some lesser formation of 2-nitroanaline.

A little known fact is that nitrogen dioxide actually reacts at room temperature (20degC) with toluene to form phenylnitromethane, where a nitro goup is actually added to the methyl group of toluene. "Phenylnitromethane has been prepared by the nitration of toluene with dilute nitric acid in a sealed tube."
Konowalow, Ber. 28, 1860 (1895). (the sealed tube probably implies heating) At higher temperatures, addition of two nitro groups on the same carbon predominates. "nitration of toluene with nitrogen dioxide at a temperature between 20C to 95C yields a mixture of phenylnitromethane and phenyldinitromethane"
Thus the reaction of the nitric acid with the toluene over a longer period of time might be through the partial decomposition of the nitric acid into nitrogen dioxide. One would also expect the moderately concentrated nitric acid to very slowly attack/oxidize the toluene, not only producing small quantities of 2-nitrotoluene, but also other oxidation products together with nitrogen dioxide. The nitrogen dioxide thus formed could then react with more toluene. Of course, unless the nitric acid was extremely concentrated, the phenylnitromethane would immediately hydrolyze under the acidic conditions (through a Meyer reaction) to form benzoic acid, the hydroxylamine simultaneously formed would no doubt immediately be oxidized by additional nitric acid, since at the 60%+ concentrations it is a reactive oxidizer. Fairly complex reaction dynamics. I do not really know what your orange byproduct is, likely a mix of different compounds, which may possibly include 2-nitrobenzoic acid (this is yellowish-white in color so would not explain the brownish-orange color).

Nitrous acid (NaNO2 and acid) can be used to nitrate phenol or analine. If concentrated mineral acids are present with the nitrous acid, mostly the para-nitro will be produced (91% yield), but if glacial acetic acid (concentrated) is present with the nitrous acid, yields of 74% ortho-nitro are possible. Ortho means the nitro is in the 2-position, adjacent to whatever other group is on the ring. Para means the nitro is on the opposite end of the ring from the other group.
The theory is that a nitrosyl ion (NO+) initially nitrates the ring, and then the resulting nitroso group gets oxidized to a nitro. ("Aromatic nitration", K. Schofield. 1980)
However, this nitrosyl ion equilibrium with nitrous acid is only present under strongly acidic conditions, certainly not when nitrous acid is in an alkaline envirorment., where it is mostly in the form of nitrite.

One source mentions that reaction of analine with nitrosonium hydrogen sulfate NO[+] [-]SO4H produces nitrobenzenediazonium salts.
NO2C6H4–N[+]ΞN
First, the nitro group is added to the analine. It is only after the acids have been somewhat diluted with water that the amino group can be diazotized, as diazotization cannot take place in extremely concentrated sulfuric acid.
"Interaction of Analine with diazotizing and nitrating Agents in Concentrated sulfuric Acid"
Mikhail V. Gorelik, Vera I. Lomzakova, Elena A. Khamidova
Research Institute of Organic Intermediates and Dyes, Moscow, Russian Federation


nitrosonium hydrogen sulfate is the same thing as nitrosyl sulfuric acid, which may be prepared by bubbling mixed nitric oxide/nitrogen dioxide gases into concentrated sulfuric acid.
(3)H2SO4 + NO2 + NO --> (2)NO[+]SO4H[-] + H3O[+]SO4H[-]

Whereas 3-nitroanaline can be easily diazotized with dilute nitrous acid, both 2-nitroanaline and 3,5-dinitroanaline require moderately concentrated sulfuric acid to be present, for formation of nitrosonium ions.

Treatment of a 1:1 ratio of nitrosylsulfuric acid to analine, using 92.5% concentrated sulfuric acid, leads to formation of about three times as much 4-nitrodiazonium salt as 3-nitrodiazonium salt. Using 95.5% sulfuric acid leads to a 6 to 4 ratio of the isomers, while 100% concentration leads to equal formation of both. The treatment of previously prepared benzenediazonium salt with nitric acid does add any nitro group.


[Edited on 28-7-2011 by AndersHoveland]

Hennig Brand - 27-1-2014 at 15:52

The first three pictures are of the picramic acid produced which was described in the "picramic acid from picric" thread. The last three pictures are of the DDNP produced from it. I used the method from COPAE to perform the diazotization reaction and produce DDNP. It is a very simple procedure. Once the picramic acid is obtained it is really all downhill from there.

The product is drying right at the moment, but I will be doing some testing soon. It can be recrystallized from acetone, by pouring ice cold water into an acetone solution of it according to several sources.

Several people have discussed DDNP performance issues with respect to density. I personally believe at this point that lousey reducer type and purity has lead to low quality and low purity DDNP in most cases. However, I did find this in TM 9-1300-214 ("Military Explosives"):

"If this material is dissolved in hot acetone and a large volume of ice water added to the agitated solution, the DDNP is precipitated as a bright yellow, amorphous powder. Recrystallization from a solvent is used to produce the tabular crystals that comprise specific grade material."


Picramic Acid.jpg - 396kB Picramic Acid (2).jpg - 249kB Picramic Acid (3).jpg - 225kB DDNP.jpg - 189kB DDNP (2).jpg - 226kB DDNP (3).jpg - 239kB

The reason the product is so clumpy is because it was squeezed very hard in paper towel in order to blot away as much water as possible after filtering.

[Edited on 28-1-2014 by Hennig Brand]

Hennig Brand - 28-1-2014 at 05:54

Well, the DDNP is nice and dry this morning. Yield was quantitative based on picramic acid. I think this is the first time I have ever gotten a quantitative yield for any synthesis. I lit a little and it flashed and made a little whomp sound kind of like mercury fulminate (but without the black/grey residue). I put about a paper match heads amount in a little aluminum foil, placed it on a concrete floor, and gave it a little wrap with a hammer which detonated it very easily. Now my ears are ringing of course. :) I said I was going to stop doing stuff like that, since I have noticed my hearing has been getting worse these last few years.

I am going to be in a more rural area in the next couple of days, so I will be testing its ability as an initiator of secondary explosives.


[Edited on 28-1-2014 by Hennig Brand]

DDNP Recrystallization

Hennig Brand - 28-1-2014 at 07:15

I have been thinking about how best to grow larger more well defined crystals of DDNP in order to improve the density and performance. Most of the common solvents for DDNP don't really have large enough differences in their ability to dissolve DDNP going from cold to hot solvent temperatures. After thinking about it a little bit I believe that slow, controlled, evaporation is a method which would probably be very effective for growing the large well formed crystals of DDNP that are desired. This process is not, however, a purification process. For purification purposes, the method involving pouring ice cold water into a nearly saturated solution in acetone could be used, if purification was desired first.

The following website does a very good job of explaining recrystallization, and crystal growing concepts, including slow evaporation.

http://www.chemistryviews.org/details/education/2538901/Tips...


[Edited on 28-1-2014 by Hennig Brand]

dave321 - 28-1-2014 at 12:54

you appear to have got a nice product.
I think the main problems people have are with the preparation of the picramic acid.

could you post the actual process you used and quantities of reagents.

also what reducing agent did you use (again amounts would be useful).

DDNP improved density crystals

Rosco Bodine - 28-1-2014 at 13:07

Here is a possible file of interest from Blaster, et al

An alternative approach is also attached

US2408059 crystallization modifiers



Attachment: DDNP improved crystals.pdf (101kB)
This file has been downloaded 1090 times

Attachment: US2408059 crystallization modifiers.pdf (367kB)
This file has been downloaded 943 times


roXefeller - 28-1-2014 at 14:17

Quote: Originally posted by dave321  
you appear to have got a nice product.
I think the main problems people have are with the preparation of the picramic acid.

could you post the actual process you used and quantities of reagents.

also what reducing agent did you use (again amounts would be useful).


https://www.sciencemadness.org/whisper/viewthread.php?tid=43...

Hennig Brand - 28-1-2014 at 16:16

Thanks for the files Rosco. His materials do look different than mine, but color etc can vary from what I have read. I have a controlled evaporative recrystallization experiment on the go right now. Acetone is being used as the solvent and the solution was placed in a little glass bowl covered in aluminum foil with a couple small holes in it. I am hoping it produces nice crystals.

The importance of free flowing crystals is clearly important from a commercial prospective, since it makes the material so much easier to handle and load. I wonder how important it really is to the hobbyist however.



[Edited on 29-1-2014 by Hennig Brand]

roXefeller - 28-1-2014 at 18:09

According to Rosco on the other DDNP thread, the free flowing character is necessary to enable self confinement of the material in a cap that doesn't have special confinement, only pressing. I think for the hobbyist less grit could be used but you'll want a confining cap.

Rosco Bodine - 28-1-2014 at 18:19

You will see a difference as improved performance for the increased density variety. For a material where the performance is marginal it makes a practical difference for which form will be found useful.

Hennig Brand - 29-1-2014 at 07:05

I tend to believe you, that larger well defined crystals giving a higher density product will perform better, since you usually have the right idea about these sorts of things. I was originally thinking that as long as the less dense material was pressed to a high density in a cap that it would perform well. I don't completely understand it, but it does seem logical that a higher bulk density of the loose material would be advantageous from a performance perspective.

Regarding evaporative recrystallization, after a couple hours of waiting, the level of the solution was not dropping at all so I poked more holes in the aluminum foil covering the small glass dish. It has been about 16 hours now since I poked all the holes in the aluminum cover and there is still about 5 mL or so of the 22 mL of acetone remaining. Ambient temperature is, and has been, about 20C.


DDNP Evaporative Recrystallization.jpg - 196kB


[Edited on 30-1-2014 by Hennig Brand]

Hennig Brand - 29-1-2014 at 15:12

The perforated aluminum cover was taken off the evaporating dish at about the 18 hour mark. There was still 1 or 2 mL of acetone left. Water was added to precipitate any remaining DDNP (no more seemed to precipitate) and wash the crystals. After filtering, the filtrate was very red (which I forgot to get a picture of). Yield from the recrystallization was about 95%. A more accurate value for yield could not be determined with the scales available to me at the moment. A small amount of material was not recovered from the sides of the evaporating dish, so the yield was likely closer to 97-98%.

The density has been increased immensely. Dark brown tabular crystals formed on the walls of the dish, which had largely fused together by the end of the evaporation. A small amount of lighter brown/yellow material was at the bottom of the dish, in the 1 or 2 mL of acetone, and looked to be cubic crystals.

The density difference really is amazing. The second picture is of the damp, high density, material right after being removed from the evaporating dish. The third picture shows one gram of unrecrystallized material on the left and one gram of recrystallized material on the right.


Evaporated DDNP Solution.jpg - 248kB Dense DDNP after Solvent Evaporation.jpg - 170kB Unrecrystallized versus Recrystallized.jpg - 221kB

Contrary to my earlier perception, it seems that this method does also purify the DDNP. Yield is also obviously very good with this type of recrystallization. Yield would be 100% (all solute recovered) if all the solvent had been evaporated. I believe some impurity was removed by adding water before the last bit of acetone had evaporated, however, given the appearance of the filtrate.

I think that little bit of lighter brown material sitting on the bottom of the evaporating dish was probably the result of my not being careful enough to ensure that absolutely all of the low density crude DDNP had dissolved before putting on the aluminum cover. Next time I will be a little more careful to verify that all material has dissolved.


[Edited on 30-1-2014 by Hennig Brand]

dave321 - 30-1-2014 at 03:59

you could make some nice lead free bullet hits with that material

Hennig Brand - 30-1-2014 at 04:44

I guess you could. I am hoping that it will also be a good initiator of secondary explosives. I am quite sure that lead azide is still higher performance and a more practical primary, in general, but it is still interesting to experiment with others.

DDNP Testing

Hennig Brand - 30-1-2014 at 08:12

Test 1:

Cap:
0.5 g PETN base charge
0.2 g DDNP primary (high density material from evaporative recrystallization)
~0.05-0.1 g basic lead picrate as flash igniter

Witness Plate Thickness:
40 thousands of an inch (~1 mm) steel plate (painted green)

A cap was made using 3/16” id aluminum tubing with about 25-27 thousands of an inch wall thickness. The PETN base charge was pressed to 1.45 - 1.5 g/cc by hand with a small wooden rod. The DDNP was pressed with approximately the same pressure as was used to press the PETN. The basic lead picrate was very lightly pressed.

In test 1 the 0.2 g of DDNP failed to initiate the PETN base charge. A picture of the witness plate after the first test can be seen with only a slight bend in it. It appears as though the bend is from the DDNP and basic lead picrate detonation.

Test 2:

Cap:
0.5 g PETN base charge
0.4 g DDNP primary (high density material from evaporative recrystallization)
~0.05-0.1 g basic lead picrate as flash igniter

Witness Plate Thickness:
40 thousands of an inch (~1 mm) steel plate (painted green)

The cap was made from the same materials as was used in test 1 and loaded in the same way as in test 1. The PETN base charge was successfully detonated this time. The 2 pictures of the hole blown through the witness plate are from test 2.

DDNP definitely doesn't detonate easily in small quantities, without confinement, the way lead azide does. So far DDNP isn't looking any better than mercury fulminate. The literature says that it is, however it also states that significant confinement is needed for DDNP to function at high performance. It is possible I need to learn how to work with it, and design caps a little differently when DDNP is used. I am pretty sure at this point that initiating picric acid with DDNP would be quite difficult the way I presently design and load my caps. It could be though that once over a certain minimum quantity of DDNP is used that it works great (I don't know). It would make sense that DDNP would require more charge weight (column height/length), than lead azide, to get up to speed.


Cap Test 1.jpg - 129kB Test 1 Cap & Witness Plate.jpg - 216kB Test 1 Failed.jpg - 213kB Test 2 Success (1).jpg - 443kB

Test 2 Success (2).jpg - 243kB


[Edited on 30-1-2014 by Hennig Brand]

Rosco Bodine - 30-1-2014 at 09:52

3/16" ID for the cap is a critical diameter concern IMO for efficient DDT of the DDNP. 5/16" ID would be better or in actuality even 3/8" would be less critical for improvised detonators. Reasonable expectation for an improvised detonator is that it won't be achieved even nearly close to the economy of usage of materials as is achieved in the highly refined commercial detonators where everything about the configuration is optimized for economy of materials, and still have a reliable configuration for the improvised detonator. Using cheap materials it doesn't matter that limitation applies, to compensate it is easiest to simply increase the dimensions of the device beyond that used for commercial detonators and the improvised cap will not be so picky about the grit size of crystals and loading pressures and confinement but will be subject to a more generalized scheme where the desired effect occurs simply as a result of the ordinary and not so highly optimized performance of the materials.

Economy and miniaturization are achieved only for a highly engineered and highly refined configuration derived from a great many tests. DDNP is a confinement sensitive primary having a DDT behavior similar to HMTD where
it will get the job done of pregressing from ignition to high order detonation but requires confinement and a generous amount of material to be there which is consumed during the run up where accelleration from ignition through low order detonation and progressing to high order detonation is occurring. The material has to reach high order detonation with sufficient mass remaining which will high order detonate to deliver the required initiatory impulse to the target base charge. So most of the initiator is burned as kindling for the fire that is the high order detonation. A larger diameter column geometrically increases the quantity of materials present but greatly decreases the linear distance for the run up accelleration when near the critical diameter, and improves the intensity of the impulse when the transition to high order occurs. There is a kind of "sweet spot" diameter range for unreenforced detonators using low sensitivity base charges like picric acid that is about 9mm or 3/8" and that diameter lowers for more highly sensitive base charges to 6mm or 1/4" for unreenforced detonators.

Depending upon the combination of materials chosen it is predictable that the device ID dimension will commonly be found in that range for a practical device of an improvised nature that is not a highly developed and highly engineered commercial design. This is a kind of general parameter and will not hold true for the exception when exotic materials being deliberately used may offset the usual limitations. It is especially challenging to make improvised detonators that are reliable and have good performance and at the same time are physically small in dimensions. Of course it is possible to do, but for that to be accomplished requires the same precision about every component involved to be duplicated as would be done by a licensed commercial manufacturer and that level of involvement with production ventures into an area of formalities and legal concerns where various licensing and regulation issues could arise as concerns beyond the science and engineering as would be the attention of a usual inventor or experimenter.

Another test which might be worthwhile, would be to increase ID to 5/16" and use a quarter gram basic lead picrate as a loose charge atop the DDNP having been just lightly pressed. The basic lead picrate will low order as a flash charge and will self compress in situ the increments below as the sequence is occurring.

[Edited on 30-1-2014 by Rosco Bodine]

Hennig Brand - 30-1-2014 at 10:16

I have always wanted to make small detonators, but yeah I think your right I may have gone too small in this case. I have used these same casings though with PETN and lead azide for initiating plastic explosives, but DDNP is different than lead azide as I am finding out more and more.

Rosco, something else that was really interesting was the color change of the DDNP going from low density material to high density material. From evaporative recrystallization the DDNP went from a yellow/brown type color to a much darker brown. When I pressed the DDNP some of it got crushed up a bit and became lighter colored again. When I looked in the cap, after pressing some DDNP, there was a mix of dark bits and lighter crushed bits. This really drove home that concept, from the azo-chlathrate thread, where the color of basic lead picrate depends on the density and crystal size.


[Edited on 30-1-2014 by Hennig Brand]

Rosco Bodine - 30-1-2014 at 10:52

There are several primary explosives which can be good initiators only under rigidly specific conditions of diameter and confinement because they lack self accelleration. A property about primary explosives exists where even the tiniest crystal or a very few crystals of a few milligrams "critical mass" will self confine and high order detonate with brisance almost instantly when touched by a glowing splint. I call the property of primary explosives like silver fulminate which exhibit that property as being "unequivocal" primary explosives, and you can sort primary explosives into 2 general groups, those that are unequivocal primary explosives and those that are not. DDNP is not an unequivocal primary explosive, but lead azide is. And the property has nothing to do with the ultimate power output possible because in this case the DDNP wins, that is DDNP is ultimately "more powerful" than lead azide once it gets going, but that is the problem you see, the conditonal or equivocation involved in "getting it going" from ignition through DDT to high order. Lead styphnate behaves similarly and is "more powerful" than lead azide but is a worse initiator because of its low self accelleration. However, mixed with lead azide 60/40 the mixture is more powerful than lead azide alone because the lead azide has a synergistic effect and kicks the lead styphnate as a homogenous booster. A similar effect is likely for DDNP in admixture with an unequivocal primary explosive. A parallel effect should occur if a sensitive secondary explosive given easily to "cook off" like ETN is grained with the DDNP which acts as a flash charge to thermally shock the sensitive nitroester and then together a faster DDT and high order detonation.

Hennig Brand - 30-1-2014 at 14:42

I do understand the concept and you have worded it well. I don't know how to quantify it exactly at the moment, but DDNP seems to be somewhere half way between lead azide and lead styphnate in terms of unequivocality. I would really like to know how the military and industrial people design their DDNP caps.

According to TM 9-1300-214 “Military Explosives”, “an unconfined sample (of DDNP) burns with a flash if ignited but even the slightest confinement causes a transition from burning to detonation. A charge of DDNP undergoes detonation when ignited if pressed into a blasting cap shell with a reinforcing cap and a piece of black powder safety fuse crimped in the shell. A spark falling into the open end of such a blasting cap causes only ignition and flashing of the DDNP.”

Those caps I made, from the above picture, were only sealed with a bit of hot melt glue at the fuse end and the cap was not reinforced. I think I can come up with something much better. I haven’t given up on DDNP yet.

Also from “Military Explosives”, “the sand test indicates DDNP is a better initiator of detonation than mercury fulminate or lead azide for less sensitive high explosives. The most marked evidence of this is the ability of DDNP to initiate the detonation of ammonium picrate and cast TNT. For initiation of more sensitive high explosives, DDNP is not superior to lead azide.”

Also from “Military Explosives”, “when subjected to the sand test with ignition by a black powder fuse, the brisance of normal lead styphnate (10.5 grams of sand crushed) is much less than that of lead azide (16.7 grams of sand crushed). “ The grade of DDNP used for military purposes, specs taken from the same text, shall crush not less than 33 grams of sand in the sand test.

The more I read about it, DDNP sounds like it would be a great initiator for picric acid and other insensitive secondary explosives.


BTW, that Chinese primary explosive presentation, linked to in the "picramic acid from picric" thread, suggested 6mm casings be used for DDNP. It looked like 6mm was recommended for all the primary explosive examples, but it still says something about suitable casing diameters for DDNP (I think).



[Edited on 31-1-2014 by Hennig Brand]

Reinforced Detonator

Hennig Brand - 31-1-2014 at 13:48

I attempted to improve my DDNP detonator design today and detonate some picric acid. A reinforced detonator was constructed. Aluminum round stock was going to be used to make the reinforced cap or insert, but was not readily available so carbon steel round stock was used instead. The outer casing was made from a piece of aluminum arrow, with inside diameter just shy of 5/16". The inner reinforced cap/insert was turned on a lathe, from 5/16" carbon steel round stock. It was sized so that it would fit snugly inside the outer casing and would need to be pressed into place. The reinforced cap/insert was drilled out for 1/4" and a 1/16" hole drilled in its end as a flash hole to except fire from the fuse or igniter. Four inserts were made, each taking about a half an hour to make.

Test
Base charge: 2.2 g picric acid from ASA (melting point indicated at least 98% pure)
Primary: 0.5 g DDNP recrystallized by evaporation
Flash igniter: 0.2 g basic lead picrate

Cap outer dimensions:
Length: 6 cm
Diameter: 9 mm

The flash igniter follow by the DDNP were pressed into the reinforced cap/insert. The picric acid was pressed into the outer cap casing (aluminum arrow piece). About 0.2-0.3 g of picric acid was poured in last and the steel insert containing the primaries pressed firmly on top. A little black powder was put in last follow by a fuse and a little hot melt glue as usual.

Witness plates:
base: 1/8" steel
side: 40 thousands of an inch steel

The DDNP reinforced cap failed to detonate the picric acid, which sort of surprised me. I was really expecting this to work.
The bottom half of the picric acid base charge was recovered with the picric acid still in place in the casing (about 1 g).

Lathe 1.jpg - 447kB Lathe 2.jpg - 493kB Reinforcing Inserts.jpg - 260kB Picric Acid.jpg - 394kB Loading 1.jpg - 163kB Loading 2.jpg - 396kB Loading 3.jpg - 267kB Cap and Witness Plates.jpg - 173kB Pre-Test.jpg - 415kB Post Test.jpg - 453kB


[Edited on 31-1-2014 by Hennig Brand]

Hennig Brand - 31-1-2014 at 14:04

The reinforced detonator description I used to help guide the design of my own came from an old technical paper put out by the bureau of mines called "The Sand Test For Determining The Strength Of Detonators" by C.G. Storm & W.C. Cope 1916. I have attached a pdf of the 3 pages describing construction of reinforced detonators.

Attachment: Reinforced Detonator Construction.PDF (971kB)
This file has been downloaded 818 times


roXefeller - 31-1-2014 at 14:56

You don't happen to have some ETN laying around to throw in the mix.

Hennig Brand - 31-1-2014 at 15:05

I do where I will be in a couple of days, but I don't today. Yeah, that might be a good idea and it has been suggested a couple times in the last couple of days. I would really like to get some inside information regarding DDNP from the people who work with the stuff for the military and industry, but that isn't likely to happen. I doubt they are mixing it with ETN, though that doesn't mean that it's necessarily a bad idea.

If I had used the same amount of lead azide in place of the DDNP (0.5 g), in the above cap and in an unreinforced configuration, the picric acid would have detonated. I have verified this several times before.

[Edited on 31-1-2014 by Hennig Brand]

Rosco Bodine - 31-1-2014 at 17:16

This patent may provide some insight


GB572729 Improvements in or relating to blasting and like detonators

Attachment: GB572729 DDNP mesh size for DDT.pdf (669kB)
This file has been downloaded 867 times

[Edited on 1-2-2014 by Rosco Bodine]

Hennig Brand - 1-2-2014 at 10:04

Good point, I was thinking that the material I was using was very coarse, but I was unsure of how much difference it made. I read the following a while ago from "Military Explosives", but like I said I wasn't sure how important it was. The bolding was done by me.

"One grade of DDNP is used for military purposes:

Color: greenish yellow to brown.
Form: Tabular crystals having a maximum length of 0.2 mm.
Granulation: 100% shall pass through a No. 100 US standard sieve.
Bulk density: Minimum, 0.4 grams per milliliter.

Acidity: Maximum, 0.01 percent as hydrochloric acid.
Sand test: 0.40 gram shall crush not less than 33 grams of sand."

Particle size is likely very important, among other things.

Edit: DDNP Dead Pressing

I have done a little more investigating and DDNP can also be dead pressed quite easily which is almost a non-issue with lead azide. I did a few calculations and tests on my loading apparatus and found that I was putting close to 30 MPa of pressure on the DDNP when loading it. This is far too much pressure for best results. Dead pressing, at the very least, results in more DDNP being required to do the same job as a lesser amount that is properly pressed. I have attached a jpg of a graph taken from chapter 2 of "Primary Explosives" by Matyas, which shows how loading pressure and specific surface (surface area per unit mass) effect DDNP initiating efficiency.

A picture is also shown of my loading press, which is basically just a class 2 lever. I did the calculations for a class 2 lever but I was still a little unsure of how much force I was actually applying to the end of the lever. A test was done where an old set of bathroom scales was put at approximately the location the cap normally would be during pressing and applied pressure in approximately the same way as I normally do. The results were amazing, for a 1/4" dowel I was easily applying 30 MPa of pressure to the DDNP. A solution to this would be to determine the desired loading pressure and then hang a weight from the end of the lever which would produce that desired pressure. This would be much better than guessing. I got away with guessing with lead azide, because lead azide can handle a much broader range of loading pressures with much less effect on performance.

Formula for class 2 lever:

Fc = Fl * (Lt/Lf)

Where:
Fc = Force on cap loading dowel
Fl = Force applied to end of lever
Lt = Total lever length (from fulcrum(hinge point) to other end where pressure is applied)
Lf = Distance from fulcrum to loading dowel

Loading Pressure is, of course, the force applied to the loading dowel divided by the cross sectional area of the dowel.

The complete second chapter of "Primary Explosives" by Matyas is also attached, as it has some very good information in it that I am still digesting.

I am also trying agitated evaporative recrystallization at the moment. A picture is attached of a small homemade stirrer being used to stir the evaporating DDNP in acetone solution.


Effect of compacting pressure and specific surface on DDNP detonator performance.jpg - 93kB Loading Lever.jpg - 245kB Loading Pressure Test.jpg - 441kB Agitated Evaporative Recrystallization.jpg - 455kB


Attachment: Primary Explosives Chapter 2 - Matyas.pdf (1MB)
This file has been downloaded 866 times


[Edited on 2-2-2014 by Hennig Brand]

DDNP Test Again

Hennig Brand - 2-2-2014 at 14:02

The crystals obtained from the agitated (stirred) evaporative recrystallization were nicely formed and about the size and colour specified as military grade in the text "Military Explosives". A reinforced cap was made with the same dimensions as the one in the previous test, but this time with the new fine crystals of DDNP and pressed with much less force. Using the above graph taken from the text "Primary Explosives" as a guide, a loading pressure of 14 MPa was chosen. The 14 MPa loading pressure corresponds to about 100 lbs of force on the 1/4" loading dowel. Bathroom scales were set on the loading press, under the loading jig, in order to determine when 100 lbs of force was applied to the loading dowel. As before 0.2 g of basic lead picrate, 0.5 g DDNP and 2.2 g of picric acid was used.

The explosive test was another failure. A big dent in the green side witness plate indicated that the DDNP had detonated, but the picric acid primary did not. The surrounding snow is now very yellow. In the near future I will try a full gram of DDNP in a reinforced cap with picric acid as the base charge. I have been experimenting with this compound almost every day for the last two and a half weeks. I am about to give DDNP the finger.

A few pictures of the recrystallized DDNP and the explosive test are attached. The microscope picture is the DDNP at 100X magnification.


DDNP Recrystallized.jpg - 238kB DDNP 100X.jpg - 210kB Picric Acid.jpg - 223kB Test Shot.jpg - 379kB Failed.jpg - 354kB


[Edited on 2-2-2014 by Hennig Brand]

roXefeller - 2-2-2014 at 20:09

But you got the DDNP to detonate... are you just hoping for a simple detonator over one with a booster. Isn't picric acid a little insensitive for detonation. The Clark journal article about DDNP shows picric acid between tetryl and TNT for sensitivity to a DDNP cap. Could the picric acid be in an non-optimal state? Rosco mentioned a 50/50 mix with DDNP that could be suitable as a booster (http://www.sciencemadness.org/talk/viewthread.php?tid=433&am...), both sensitive and brisant.

Off topic, but what did you use to close the bottom of the AL tube you've been using for the cap?

[Edited on 3-2-2014 by roXefeller]

Ral123 - 3-2-2014 at 00:31

Thanks for that nice pdf Hennig Brand. I test my materials with a straw test. Can it be set off(with fuze and or AP/LA) in a straw and detonate all the way. TNP didn't go off in a straw with AP, but it did go off with LA/Tetryl and detonated all the way in that straw.
Will the confinement of a straw be enough for the DDNP to detonate? If not, may be it's useful at 2g+ with the basecharge optional :D

Hennig Brand - 3-2-2014 at 02:51

Quote: Originally posted by roXefeller  
But you got the DDNP to detonate... are you just hoping for a simple detonator over one with a booster. Isn't picric acid a little insensitive for detonation. The Clark journal article about DDNP shows picric acid between tetryl and TNT for sensitivity to a DDNP cap. Could the picric acid be in an non-optimal state? Rosco mentioned a 50/50 mix with DDNP that could be suitable as a booster (http://www.sciencemadness.org/talk/viewthread.php?tid=433&am...), both sensitive and brisant.

Off topic, but what did you use to close the bottom of the AL tube you've been using for the cap?



The DDNP is definitely detonating, but it just isn't giving the picric acid the kick it needs. What is the optimal state for picric acid when functioning as a base charge? I think this would mean pressed to not too high a density and finer crystals also maybe. For this last test I crushed up my large picric acid crystals, from the above picture, to make the material finer before loading. The picric acid was put in a fold of printer paper and the back of a spoon was run over it a few times, with pressure, to crush the large crystals.

The idea of DDNP mixed with TNP may be a good one. I wonder if having a base of picric acid followed by a mixture of picric acid and DDNP followed by pure DDNP on top would be a good configuration. If you wanted to get fancy, the mixed DDNP-picric acid section could incrementally increase in proportion of DDNP until the top where there would be pure DDNP.

A disc of aluminum cut from the top of a beer can was used to seal the cap bottom end. It doesn't matter how the end is sealed much anyway, in this case, given the amount of compacted TNP pressed in on top which seals in the material above it quite well and provides confinement.

I made another 4 carbon steel reinforcing caps/inserts, so I still have six left. I will do another couple tests in the next while.

@Ral123
No problem, glad to help other experimenters.

This same picric acid has been detonated in the aluminum arrow tubing, several times, using 0.4-0.6g of lead azide.

Yeah, the DDNP might do well on it's own in 1 or 2 gram quantities in a cap without a base charge. According to the literature it has performance more similar to base charge material than primary explosive material anyway. A couple grams (or less) of pure DDNP might initiate a main charge of picric acid or TNT just fine.


[Edited on 3-2-2014 by Hennig Brand]

Ral123 - 3-2-2014 at 09:42

I'm worried about the high flammability of Tetryl and RDX if used in their sensitive crystaline form, I don't know what to say about massing up TNP and DDNP for boosters :/ It reminds me of a mixture called APAN :D
I've considered using lead picrate contaminated with TNP as a base charge when the primary is weak.

Hennig Brand - 3-2-2014 at 10:53

DDNP is one of the least sensitive primaries, reasonably stable and compatible with picric acid. I wouldn't compare a mixture of DDNP and picric acid to APAN. Picric acid, judging from pretty much everything I have read, is only a little more sensitive than TNT. Tetryl is much more sensitive than TNT. I can look up some figures and post them if need be, but they are easy to find. My picric acid does seem a little harder to initiate than I feel it should be, but it tests very close to pure by melting point.

DubaiAmateurRocketry - 3-2-2014 at 11:13

is 5-Nitrominotetrazole a suitable primary? it has a high VoD and acceptable impact sensitivity of 6cm H50 2.5 kg drop height

Ral123 - 3-2-2014 at 11:57

The APAN comparison was a bit of trolling, the TNP/DDNP mixture will be much more stable, robust and powerful, surely can be a basecharge.
If 0,5g of primary cant set off TNP while surrounded by all that metal, I can't consider it reliable. Don't get me wrong, it surely hits much harder then AP, but considering my success to initiate TNP with it, with the confinement of cardboard, I think something is not right with the DDT of your DDNP. Only the DDNP in your setup has more energy then a gram of silver azide. I can't see how can it be reliable with conventional cap No8 configuration. May be it's like styphnate, only good for ammunition primers.

Hennig Brand - 3-2-2014 at 13:04

How much acetone peroxide did you you use to detonate your picric acid and at what diameter?

Ral123 - 3-2-2014 at 13:21

May be no more then a gram if my feeling of volume and density is not mistaken me, but here's the test: http://www.youtube.com/watch?v=t5AUT48E7w4 As a matter of fact, the TNP I suspect is highly nitrated, as I used quite a lot of WFNA/H2SO4 and a gram of primary ain't little.
Doesn't your designs have too much wall/bottom thickness, preventing good shock wave transfer? I love my azide-Tetryl straws.

Hennig Brand - 3-2-2014 at 13:43

Interesting video. The inside diameter of that charge looks to be at least 3/8" and maybe closer to 1/2"(I measured a similar lighter with vernier callipers). I have been using 5/16" diameter aluminum tubing, which probably gives stronger confinement but less diameter. A little extra diameter might make a big difference to how easily picric acid is initiated.

Those critical diameter specifications from the text books are best case scenario, with ultra pure picric acid. A little less purity or density difference (or whatever) and the critical diameter could become significantly larger (I think).

Ral123 - 3-2-2014 at 14:20

The diameter is exactly 9mm. And I like giving the primary some distance to develop it's velocity.
For the DDNP, may be the confinement factor is the only thing left. I suspect the arrow tube can still make good cap. Here's how I've sealed the bottom by bending material inwards and hammering down some Al foil for extra seal: http://youtu.be/luj3NdyBisA?t=37s That way the bottom is both thin and strong. For the upper part: e-match, some inert/heavy/incomressible powder and than epoxy. The gases won't have anywhere to go and may be most of the material will be detonated with high velocity.

Hennig Brand - 3-2-2014 at 17:02

The aluminum arrow is just a hair under 5/16" id (~7.6-7.8mm), which is significantly under 9mm. "Propellants and Explosives" By Naminosuke Kubota, gives the critical diameter of picric acid as 6mm. I wonder if it's kind of like fat people losing weight. You know, the first ten pounds does much more for their health than the ten pounds after that, and so on (so they say). If the critical diameter is 6mm for picric acid, going from 7.6mm to 9mm might make one hell of a difference.

I wonder how much impurity it would take in a picric acid sample to raise that critical diameter from 6mm to 7mm. I am guessing probably not that much.

[Edited on 3-7-2014 by Polverone]

Rosco Bodine - 3-2-2014 at 17:14

Quote: Originally posted by Hennig Brand  
Interesting video. The inside diameter of that charge looks to be at least 3/8" and maybe closer to 1/2"(I measured a similar lighter with vernier callipers). I have been using 5/16" diameter aluminum tubing, which probably gives stronger confinement but less diameter. A little extra diameter might make a big difference to how easily picric acid is initiated.

Those critical diameter specifications from the text books are best case scenario, with ultra pure picric acid. A little less purity or density difference (or whatever) and the critical diameter could become significantly larger (I think).


It is virtually impossible for an individual to reproduce exactly the same scale of detonator as is made by professional ordnance manufacturers, using special techniques and trade secrets that exploit economy to the fullest for a mass produced item. What can be done is to duplicate the general principle in a less highly refined implementation where the general principle is reduced to practice.

AP can definitely detonate picric acid but it has to be a special configuration using generous amount of the AP used for the initiator. The configuration described worked with the ball of putty used to hot start and compress in situ the firing train. Without the AP / Bullseye putty for the top charge the device failed. But with that quarter gram as first fire, the device worked fine. The details are in the links here.
http://www.sciencemadness.org/talk/viewthread.php?tid=179&am...

http://www.sciencemadness.org/talk/viewthread.php?tid=179&am...

http://www.sciencemadness.org/talk/viewthread.php?tid=179&am...

Most interesting among the AP variants would be the terameric AP
http://www.sciencemadness.org/talk/viewthread.php?tid=179&am...
My thoughts about isolation and purification of AP would be beneficial due to the inclusion of water in AP as crystallized from aqueous reaction mixtures, so it would probably be a good scheme to dissolve the AP in hot toluene and decant from any crystal water which settles out or easier pipet the water globule away, and precipitate anhydrous AP with methanol added to the hot toluene.

Likewise for AP is the DDT operating principle applicable for HMTD and DDNP which have in common with AP the same lack of unequivocality, slow self accelleration and a larger than ideal critical diameter, particularly true and more evident for an improvised configuration no matter how refined it may be thought by the improviser that such configuration is. An improvised detonator is still unsophisticated and crude compared to the detonators made by professional ordnance manufacturers, who simply don't publish all the details of everything done. Almost nothing about the initiating quantities reported in the literature will ever translate directly to what is found to be the case by direct esperimentation to confirm. The general
principles will hold true but your numbers won't be close to their numbers for a working device, a multiplier will apply.

If you get similar performance at 150% as a minimum of what is reported, then count that as excellent. 200% or even more would be the more common result as a materials demand for an improvided device.

Not mentioned very often is the fact styphnic acid is almost an equally good base charge as is picric acid and styphnic acid is more sensitive to initiation than is picric acid requiring perhaps 20% less impulse to initiate.

[Edited on 4-2-2014 by Rosco Bodine]

Hennig Brand - 3-2-2014 at 18:29

It's not that I ever disagreed with you on this, but let’s just say I agree with you a lot more than ever. Trying to replicate those published numbers is cruel and unusual punishment and will just result in unreliable blasting caps. I know this has been discussed to death, but things often take a while to sink in (at least for me).

That work you did, detonating picric acid with acetone peroxide, is interesting and telling. Do you remember 4 or 5 years ago when I posted about trying to detonate picric acid with acetone peroxide? By the end of it I had a full gram of AP pressed really hard in a vise, on top of 1.5 or 2g of picric acid, in a 3/8" aluminum tube. I was watching from behind cover and what I saw when the acetone peroxide detonated was a big yellow cloud of vaporized picric acid.

I have been sort of off and on questioning how pure my picric acid is for the last few years. It really is just insensitive stuff, especially if conditions aren't just right.

[Edited on 4-2-2014 by Hennig Brand]

Rosco Bodine - 3-2-2014 at 18:57

BTW a reenforcing cap is generally a short length to diameter like 1:1 and is domed like freeze plug for an engine block, flattening the dome and pressure laterally inside the skirt expands the diameter and locks the inverted cup in place. Not all of the initiator is necessarily confined within the reenforcing cap but maybe only the first fire or small increment of the initiator, which may have full bore diameter in its main increment length atop the base charge.

DDNP of smaller mesh mixed 70/30 with KClO3 or KClO4 and then utilized in greater quantity not strongly pressed would likely be an improvement. A loose flash charge of basic lead picrate in sufficient amount to low order detonate on ignition, like a quarter to a third of a gram, would give a hot start and in situ compression, to the chlorate sensitized mixture which should then high order more easily.

[Edited on 4-2-2014 by Rosco Bodine]

Hennig Brand - 3-2-2014 at 19:09

Thanks, yeah the old document I was using as a reference had pretty sparse details regarding reenforcing detonators. I had to read it 3 or 4 times to even figure out what I did.

What I could do with the reenforcing caps I have is to press one or more locking, domed discs in on top of them. These discs would need to have center holes drilled in them before loading. I guess making the reenforcing caps a little shorter might be in order too, since I made them to hold the whole primary charge.

Good ideas, regarding mesh size reduction and (per)chlorate admixture. I have been heading towards smaller mesh size lately actually. The agitated evaporative recrystallization method could easily produce any mesh size you wanted with a little fine tuning.

[Edited on 4-2-2014 by Hennig Brand]

Ral123 - 3-2-2014 at 23:29

What did you have above the AP, maybe a little putty and then epoxy would give good confinement. Also, maybe two grams would've developed higher pressure and velocity at the TNP. In my test I had most of the TNP hammered with a bolt, but some was hand pressed like the AP.
In the suggestion of the arrow tube, I had in mind pure DDNP or DDNP>2g and the rest is crystaline secondary. As for the critical diameter, in a test, the TNP detonated all the way in a straw, so in the confinement of the arrow tube it's sure to do well, at the right density.

Rosco Bodine - 4-2-2014 at 04:47

Quote: Originally posted by Hennig Brand  
It's not that I ever disagreed with you on this, but let’s just say I agree with you a lot more than ever. Trying to replicate those published numbers is cruel and unusual punishment and will just result in unreliable blasting caps. I know this has been discussed to death, but things often take a while to sink in (at least for me).


The context of laboratory tests done under rigid conditions for a particular sample is important to be understood applies only with specificity to that sample and to that series of tests, and there are variables that will cause your own tests of a different sample under conditions that are not identical to be different. If the context is not given as much consideration as it should be then it can easily lead to faulty analysis and faulty conclusions about your own test results which should only be expected to generally follow a trend identified by other researchers, and not necessarily show identical results. Only the general principle should be expected to hold true, not exact verbatim duplication like a carbon copy of what was reported by others. Criticality is the factor involved when when certain tests done by others are not being reported with emphasis that their work is being done with optimization of every parameter with an object of economy of materials as would interest investors in some patented process which is being marketed. So an inventors euphoria and salesmanship may cause glorification to be applied to reported results bordering on making false representation. Understanding that is a motivation for the content of published literature because of the nature of the scenario involved, should cause some skepticism and cynicism to apply while reading the reports with a certain reservation until verifying what is reported and understanding the context more completely.
Quote:

That work you did, detonating picric acid with acetone peroxide, is interesting and telling. Do you remember 4 or 5 years ago when I posted about trying to detonate picric acid with acetone peroxide? By the end of it I had a full gram of AP pressed really hard in a vise, on top of 1.5 or 2g of picric acid, in a 3/8" aluminum tube. I was watching from behind cover and what I saw when the acetone peroxide detonated was a big yellow cloud of vaporized picric acid.

I didn't follow your experiments. But obviously a "full gram" of AP thought to be "enough" is a faulty premise, and could lead to faulty conclusions which is illustrative of the issue. Working up a loading is a practical matter that follows a certain course. When you have only half what is required to do the job then there is no getting past doubling what you incorrectly presumed would be enough, understanding the presumption was incorrect. A premise that is faulty will skew the analysis and conclusions every time.
Quote:

I have been sort of off and on questioning how pure my picric acid is for the last few years. It really is just insensitive stuff, especially if conditions aren't just right.


It is likely that your picric acid is fine. It is also likely that you have some faulty understandings about its properties in response to various schemes for its reliable initiation which cause you to believe it is easier to detonate than it actually is. The literature which exaggerates and falsely represents that picric acid is more sensitive than it actually is has skewed your expectation so that you somehow expect that picric acid should be easier to detonate than it is. Picric acid is quite insensitive to initiation and has to be subjected to a pretty extreme provocation to cause its detonation. If you have problems getting picric acid to detonate then the issue is very simple, and that is that you haven't gotten extreme enough yet in the delivery of an initiating impulse to the target material to provoke its detonation. Because when that threshhold is crossed then the picric acid or any other energetic material capable of detonation, will in fact be detonated, not by anybody's expectation of what the material should do but simply because of the laws of physics.

You are understanding that crystal mesh and form is important, but then have unreasonably focused upon a scheme of "solvent evaporation" as some sort of special technique presumed to be somehow advantageous when that premise has no basis other than what is your expectation. It may be that you are operating on a faulty premise and that other factors are more important.

Read the linked post with its references

http://www.sciencemadness.org/talk/viewthread.php?tid=389&am...

and this also

http://www.sciencemadness.org/talk/viewthread.php?tid=22810&...

I would again reiterate what I have said before that you can do any materials testing for proof of concept using a polypropylene test tube. It doesn't require elaborate equipment but some basic fixtures and dies and shields for safety concerns. Tool and die shop prototyping is another level and then mass production is yet another. Basically it is no more difficult to handload ammunition or detonators but for the availability of raw materials that are the components and having the knowledge gotten from materials testing to assemble the components needed to do the job. Looking for any 1-2-3 ABC "you tube" tutorial on detonator manufacture is a way to go for some folks but I'm not going there. Good information about detonators is a hundred plus years old technology that is ubiquitous and those people who would need every minute detail spoon fed to them likely don't have the wits to be trusted with doing anything constructive with the information. If detonator technology is left mysterious for some people then that is probably an inherent safeguard that is prudent like not letting children play with matches.

Hennig Brand - 4-2-2014 at 09:16

Thanks for the good links; they have cleared up a few things for me. For one thing, DDNP does have its virtues which are now more clear. I am definitely going to try the 75-25 DDNP-Potassium Chlorate mixture.

Quote: Originally posted by Rosco Bodine  

You are understanding that crystal mesh and form is important, but then have unreasonably focused upon a scheme of "solvent evaporation" as some sort of special technique presumed to be somehow advantageous when that premise has no basis other than what is your expectation. It may be that you are operating on a faulty premise and that other factors are more important.


The reason I have been focused on the solvent evaporation method is because I haven't seen anything disclosed in the literature about recrystallizing DDNP, except for the purification technique involving dumping ice cold water into a DDNP solution in acetone. That process works for purification but not crystal size control. In the absence of any technique, I read about recrystallization and picked a method that seemed appropriate. It seems to be very easy to control, though it can be a bit time consuming. Vapor pressure of the solvent is controlled by temperature and the rate of vapor release can also be controlled by the amount the evaporating vessel is sealed. Agitation can be varied also, which I have found is very important.

Having no basis is not really accurate. I did review some of the common solvents and attempted to work out some sort of normal slow cooling method, but found most of the common solvents were not really appropriate. Also the evaporative recrystallization technique was studied a bit by me (admittedly briefly) and the techniques and advantages and disadvantages are well documented and tested by others.

The solvent evaporation method is a bit of a novelty for me, because I hadn't heard of it being done with DDNP. If you have a better solution (pun intended), that you know works, let me know.

Quote: Originally posted by Rosco Bodine  

I would again reiterate what I have said before that you can do any materials testing for proof of concept using a polypropylene test tube. It doesn't require elaborate equipment but some basic fixtures and dies and shields for safety concerns. Tool and die shop prototyping is another level and then mass production is yet another. Basically it is no more difficult to handload ammunition or detonators but for the availability of raw materials that are the components and having the knowledge gotten from materials testing to assemble the components needed to do the job. Looking for any 1-2-3 ABC "you tube" tutorial on detonator manufacture is a way to go for some folks but I'm not going there. Good information about detonators is a hundred plus years old technology that is ubiquitous and those people who would need every minute detail spoon fed to them likely don't have the wits to be trusted with doing anything constructive with the information. If detonator technology is left mysterious for some people then that is probably an inherent safeguard that is prudent like not letting children play with matches.


I hope you’re not talking about me. I am not always the quickest to catch on, but I play with picric acid mostly just as a challenge. If it was really just about practicality I would just stick with PETN base charges. I have known for a long time that if I increased the charge diameter that picric acid would shoot much more easily. I resisted making really large diameter caps because I felt that they were not that practical and was hoping that I would be able to make it work properly in smaller diameters, which I guess was unrealistic. Picric acid seems to be much better suited as a booster or main charge than a component of a compound cap. It can be made to work, I am not denying that.

[Edited on 4-2-2014 by Hennig Brand]

Rosco Bodine - 4-2-2014 at 13:28

What I meant by saying there is no basis for your expectation involving solvent evaporation as a crystallization method is specific to DDNP and not as a general rule for recrystallizations. It introduces an unknown that is not described in the literature related to modifying the crystal form or mesh of the DDNP. So you end up with a product that is unique to your process since it is not a manipulation described by others. It may coincide with the work others have done and it may not. You can't do anyhting different from what is reported and then fairly compare what is your result doing differently what others may have done a different way. Crystallization varies widely and this involves a property that definitely can have bearing on the behavior of an energetic material. It is a physical parameter like progressive pressure loading that has at one end of a column a certain density gotten by high compression reduced incrementally to a loose powder in the first fire ignition zone. That scenario might DDT high order every time, while one uniformly compressed column of the identical material may only burn like a rocket fuel grain and never even low order. And a change in the mesh size or crystallization method could have the effect that both go or both no go, or no change whatever. It is an unknown that is a variable being introduced.

Hennig Brand - 4-2-2014 at 14:26

You could have a point there, I don't know. The DDNP solution is constantly pushed ever so slowly into oversaturation, growing the crystals in the process. Evaporation seems different but really what is happening is very similar to a slow cooling or a slow addition, just different ways of manipulating the concentration or in the case of slow cooling the solvents ability to dissolve the solute. I am really just a hobby chemist, but I was under the impression that the crystals formed were usually more of a property of the molecule being crystallized. I know there are examples of the same chemical crystallizing in different ways depending on solvent used, etc, but as a general rule the type of crystals formed has to do with the type of molecule being crystallized (I think).

BTW, congratulations on reaching 5000 posts. Holy Smokes! You have made a lot of good contributions. Keep up the good work.

Rosco Bodine - 4-2-2014 at 15:23

Something you have to consider when critical diameter is involved is it will be limiting as a minimum what is the larger critical diameter of any component.
For example at a critical diameter of 6 mm for picric acid and a critical diameter of 8 mm for some primary or perhaps 9 or 10 mm for another primary, the larger value would govern the ID for a cylindrical capsule unless it was stepped in diameter by a bushing of some kind used to couple the increments. You can get picric acid to detonate at 1/4" column diameter but it requires an initiator like lead azide that will also develop the needed impulse with regards to that diameter which won't quench the initiator. It wouldn't work with AP instead of lead azide at the smaller diameter. It can easily happen that the geometry of what amounts to being a ribbon charge of the initiator, is what is needed for the portion of the column of initiating explosive remaining after most of the column height of initiator has already deflagrated and/or low ordered in the run up as kindling for the fire that will be the high order impulse of the remaining portion of the pellet that then operates high order as a ribbon charge. The increase in charge weights for an increasing scale device to operate tend to follow a geometric increase meaning if you double the diameter it takes four times the amount but less some of what is gained by the faster run up of a larger diameter charge. It generally won't reduce to a mathematical doubling of the charge to get twice the output from a detonator scale device at the same diameter nor will it square for the doubled diameter but will fall somewhere in the middle of that range. At near to the critical diameter every detail becomes more critical to be exactly correct. Getting comfortably larger than the critical diameter it is easier to design a configuration having highest reliability, but at the expense of economy of materials.

[Edited on 4-2-2014 by Rosco Bodine]

Hennig Brand - 4-2-2014 at 19:32

Makes a lot of sense. Yeah, cross sectional area is proportional to the square of the diameter. Doubling the diameter yields 4 times the cross sectional area, which also yields four times the volume of explosive for a given height. I am definitely going for 3/8" or 9mm id for my next test. Most of the time there really is no issue with having caps a little bit jumbo. I like the little ones with PETN in them for plastic explosives, especially when using small charges, but for normal blasting there is really little problem with the bigger ones. What I really like about DDNP is that it is made from picric acid and a few other very basic reactants. Basic lead picrate is also made from picric acid. Strong blasting caps made from aspirin, gotta love it!

Rosco Bodine - 4-2-2014 at 20:55

Yes the versatility of picric acid considering its useful derivatives and its easy source materials puts it in a unique role which makes it explosives 101.

For the initiator of a small diameter column of explosive as is the base charge of a detonator, confined at near to what would be its critical diameter, it has been my observation and resulting theory as follows:

For an initiator, the function is similar as the concept of a platter charge, where the effect of a ribbon charge is observed, which obeys shaped charge scaling rules similar to a shallow angle cone platter charge geometry approaching or configured as a flat disk. There is an optimum geometry of diameter to thickness of the disk that is the increment of initiator undergoing high order detonation which favors a directed concentration of the output wave perpendicular to the surface of that disk and parallel to the axis of the disk. Of course the axially directed effect is augmented by confinement similar to a gun barrel, but there is a fundamental directivity of the shock wave that is focused axially by the geometry of the initiator alone, even if there is no confinement for the initiator.

http://en.wikipedia.org/wiki/Misznay%E2%80%93Schardin_effect

How far up in scale away from the critical diameter the effect may hold true that geometry is an important factor I am not sure, and the geometry that is optimum probably varies for different explosives.

It is a reasonable conclusion that follows that for a given initiator and base charge pair there will exist a practical minimum diameter which governs the lower limit for economy of materials involved in coupling the output of the initiator to the base charge to produce a reliable device that operates comfortably within design limits, not subject to failure for being adversely affected by small variables inherent to the system or any of its components.

[Edited on 5-2-2014 by Rosco Bodine]

Ral123 - 4-2-2014 at 23:38

If my TNP detonates in 5-6mm straw, then I can't see problem at 9+mm and metal confinement. I suppose nice "old school" cap can be made with 1cm copper tube, 2g DDNP and 2g+TNP. But I can't trust that primary anymore :/ There are cigar tubes that are like 1,5cm+ diameter and have fine thin walls from stainless steel or aluminium. I guess they can make a good TNP booster. May be they can have a removable thick walled DDNP element in them also.

Hennig Brand - 5-2-2014 at 04:35

I wouldn't trust a picric acid cap to function reliably at 5-6mm id with any primary. The tolerances would be tiny. You’re talking about being below the critical diameter and very weak confinement. Having at least 2 or 3 millimetres over the critical diameter provides reliability. Not suggesting that picric acid at 6mm can't detonate, just that except for some sort of test it doesn't make sense to make caps that way.

@Rosco
I just read through the patent regarding the blasting caps with the cavity or shaped charge effects. Very good idea and they could be easily made. A loading dowel with a cone shaped tip could be made to press the picric acid. A reinforcing cap over top of the primary and you would be in business. The amount of secondary in direct contact with the primary is also much more with this design.

[Edited on 5-2-2014 by Hennig Brand]

Rosco Bodine - 5-2-2014 at 09:30

When working up a load for a detonator using various components it requires systematic testing of performance that is identical in many ways to working up a load for ammunition. Theory only puts you in the ball park for where testing begins and then the charting of weights and results follows typical experimental approach.

As the load approaches critical diameter every parameter becomes more critical and works against reliability. For a carefully made metallic cap a 1/4" ID which is 6.35 mm is comfortably above the critical diameter for picric acid or styphnic acid, particularly if the initiator is lead azide and there is a bit excess used to assure reliability.

Generally what would occur for initial testing would be a greater amount initiator than is needed to assure detonation would be used and then the amount would be reduced incrementally until a failure occurs, and then the amount incrementally increased again to find the point of minimum where about 5 of 5 fire successfully and then that loading will be mulitplied by 150% t0 200% to be a standard loading acceptable designated minimum. Whether the device is being tasked or not in a "mission critical" role would have bearing on the amount of headroom that is built into the device and what is the degradation of components allowable before failure becomes likely.

There are different design criteria for a detonator to be used for general blasting utility uses and a detonator to be used for warhead activation in an expensive weapons system.

A farmer blasting a stump or a boulder wants a blasting cap that is cheap and if 1 of 500 detonators doesn't work correctly as the predicted failure rate, it isn't a situation causing much safety concern or poor economy for waste. However, for the different case where ordnance is needing a detonator which may be the least expensive component in what may even be a million dollar cost weapon, there is a desire and an economics that is very different and a different standard of guaranteed reliability changes what are the acceptable design limits which must be applied regardless of the cost or scale of the detonator where different requirements than economy govern.

The economics which may govern the manufacture of detonators used in land mines or cluster bombs will incline towards keeping it cheap for mass production even if perfect reliability is not guaranteed. But the detonator used in a naval torpedo or a guided missile will likely be the Cadillac of detonators and there will be more than one for redundancy.

So the sophistication and complexity of the detonator is something that can cover a broad range from minimal and cheap to elaborate and advanced and expensive, depending upon the application requirement. Detonator design covers the range of materials science and tooling requirements from basic to elegant depending upon what is the intended purpose. There definitely will exist what may be identified as "ideal configurations" for various purposes. Some of those configurations may be published and patented but it would be no surprise that many or most such configurations are trade or state secrets and are not published anywhere.



[Edited on 5-2-2014 by Rosco Bodine]

Rosco Bodine - 5-2-2014 at 11:47

Quote: Originally posted by Hennig Brand  
I wouldn't trust a picric acid cap to function reliably at 5-6mm id with any primary. The tolerances would be tiny. You’re talking about being below the critical diameter and very weak confinement. Having at least 2 or 3 millimetres over the critical diameter provides reliability. Not suggesting that picric acid at 6mm can't detonate, just that except for some sort of test it doesn't make sense to make caps that way.

It actually doesn't have to go that far over the critical diameter to get relief from the precision required, Fractional millimeter changes are enough to see real changes occur involving the criticality of a configuration. Small geometry changes can have profound effect. Likewise for other parameters. Don't overcompensate when seeing effects that are defined by precision. You can go wide with overcorrection to compensate for small variations when it isn't necessary to solve a design or configuration problem.
Quote:

@Rosco
I just read through the patent regarding the blasting caps with the cavity or shaped charge effects. Very good idea and they could be easily made. A loading dowel with a cone shaped tip could be made to press the picric acid. A reinforcing cap over top of the primary and you would be in business. The amount of secondary in direct contact with the primary is also much more with this design.


Actually it is more work than necessary and it introduces additional design issues to try to use shaped charge effects. The deformation pressures laterally from a wedge used as a ram complicate capsule and die requirements and it just isn't necessary. The patent simply shows a general concept and it may even be inverted to what is actually occurring for an enhanced initiator, backwards to what is needed for the actual geometry applicable to the concept. I wouldn't go there to try to solve the problem of geometry which I described involving the platter charge or ribbon charge behavior of the initiator, attempting to make it jet like a shaped charge, but simply to be aware the effect is there which can affect loading and the geometry of the disk that is the compressed initiator portion of the firing train. A low order detonating flash charge as first fire almost serves the same purpose as a reenforcing cap and it compresses in situ the elements of the column when that flash charge detonates it is also doing the work of physically compressing the increments below that flash charge along with providing ignition, and may even cause sympathetic detonation of the initiator from the pure compression ahead of the ignition. You have a virtual reenforcing cap that is a shock wave and a wall of fire and pressurized gases being provided by the flash charge.


[Edited on 5-2-2014 by Rosco Bodine]

roXefeller - 5-2-2014 at 14:55


Quote:

AP can definitely detonate picric acid but it has to be a special configuration using generous amount of the AP used for the initiator. The configuration described worked with the ball of putty used to hot start and compress in situ the firing train. Without the AP / Bullseye putty for the top charge the device failed. But with that quarter gram as first fire, the device worked fine.


What is the function of the AP in this putty? Is the bullseye not sufficient as a first fire?

Rosco Bodine - 5-2-2014 at 16:12

AP putty made as described low order detonates on ignition, and in sufficent quantity would likely high order detonate without too much of a run up distance.
But it does shrink as the acetone evaporates so forming a ball or a short molded cylinder of the still soft material before it dries completely rock hard can be done to make this little "first fire" charge hammer for a 1.75 gram 3/8" diameter column of gently pressed AP crystals situated below, atop a 1.5 gram picric acid base charge. It should high order the base charge nicely if my test hold true.
Using the tetrameric variant of AP should even more greatly assure the desired result. However this kind of thing is in the realm of a ghetto improvisation, strictly low tech kind of near term use solution. Getting too involved with such a pursuit would likely turn out to be a short term activity for the recently departed, or the survivor called "Lefty" who uses a seeing eye dog.

roXefeller - 5-2-2014 at 17:28

Just to be concise, you are saying that both the trimeric and tetrameric AP are storage unstable. I can read your statement both ways (trimeric stable/tetrameric unstable or both unstable). But I suspect, given the nature of AP, you are reaffirming both are storage unstable.

[Edited on 6-2-2014 by roXefeller]

Rosco Bodine - 5-2-2014 at 19:14

To be precise I said no such thing about either one. Both are chemically stable unlike HMTD which is not chemically stable. There is a high vapor pressure about acetone peroxide slightly lower for the tetramer but it puts the material in a state of constant recrystallization at ordinary temperature due to the continuous sublimation and condensation and crystallization of vapors where the container functions as a heat pipe with a random orientation, and the system is always in flux with recrystallization resulting in density change and larger crystals. It is not liable to just spontaneously explode in my experience, but the physical behavior is undesirable and even unnerving as a physical behavior for an explosive that seeks any crevice into which it may occupy and crystallize, which may include the threads of any container closure. It is like an accident waiting to happen. The vapor pressure is high enough that the material is used as a fumigant for extermination and/or repellent effect for insects in silos of flour or grain. But the vapor is also an added flame hazard where the flame kindled does not just reach and ignite a fuel but a flammable explosive that will do much more than simply burn when ignited accidentally, such as by static electricity.
All things considered it is the physical properties more than any chemical stability that is what is worrisome about AP. The ease and cheapness of making it also breeds complacency and carelessness about its handling which makes it seem less dangerous than it is. Eventually a handler of AP becomes clumsy or careless made more likely by the nature of the material which is a kind of insidious danger.

[Edited on 6-2-2014 by Rosco Bodine]

roXefeller - 5-2-2014 at 19:34

Quote: Originally posted by Rosco Bodine  
However this kind of thing is in the realm of a ghetto improvisation, strictly low tech kind of near term use solution.


I apologize for putting words in your mouth. I read the above and that's what I concluded. It is exactly what you said in response that makes me question the necessity of AP in the putty. But given your tests, I would agree that it is needed as far as the parameters of your testing go. At least it is easy to create, but the short work in synthesizing it should allow for extra time for careful handling.

Why doesn't the in situ compression from this first fire overcompress the initiator to a dead pressed state?

Rosco Bodine - 5-2-2014 at 19:42

The volatility of the AP and the lack of storage stability for the putty would make necessary the near term use, for example a few days to a week or so, versus months later anticipated use of the assembled detonator, unless it was hermetically sealed. Not all initiators can be dead pressed and AP isn't one that is subject to dead pressing, which is a kind of misleading term anyway. A dead pressed initiator will no longer be able to ignite and make the DDT in the usual way from ignition, but will fail to ignite or quench after ignition. Even a dead pressed initiator will still assuredly detonate if it is initiated by even a portion of itself that isn't pressed so firmly. It becomes "dead" only in response to ignition, not "deactivated" in some magical way so that it won't detonate at all.

[Edited on 6-2-2014 by Rosco Bodine]

Success

Hennig Brand - 6-2-2014 at 11:57

Picric acid (1.5g) was pressed into the ~7.6mm id aluminum arrow shaft with a lever press and an addition 0.5 g was pressed on top by hand. DDNP (0.5g) was pressed into a reinforcing cap (1/4" id) and an additional 0.5g, for a total of 1g of DDNP, was pressed on top of the picric acid. Care was taken to not overpress the DDNP. The reinforcing cap was then pressed into place in the detonator casing. Because of guesstimating, instead of measuring, the casing was just barely big enough and there was not enough room left to press in locking discs on top of the reinforcing cap. A bit of black electrical tape was used to hold a bit of black powder and the fuse in place on top of the cap. To summarize, 2g of picric acid and 1g of DDNP was used. DDNP ignites very easily so it was decided that a flash igniter was not needed. The DDNP used was not recrystallized, it was simply washed with small amounts of ice cold water after filtering, from the post reaction mixture, and then air dried.

The witness plate is 1/8" steel. The center hole was there before the blast and is the pilot hole from a hole saw.

A lovely sharp crack was heard at detonation and peering from behind cover a moment later a little puff of black smoke could be seen drifting away. A hole was punched through the witness plate. What a lovely scene.

The big thing with picric acid, as I am continually learning, is to not be stingy with the primary. It takes a considerable kick to get it going.


DDNP Unrecrystallized.jpg - 393kB Cap On Witness Plate.jpg - 471kB Top View.jpg - 489kB Bottom View.jpg - 468kB

Edit:
Just measured the steel witness plate today, with vernier calipers, and it is actually about 3mm thick not 1/8" (3mm is about 94% the thickness of 1/8").

[Edited on 7-2-2014 by Hennig Brand]

Ral123 - 6-2-2014 at 12:30

Nice test mate. Why is the BP there, it can reach pressures witch can ruin the fragile setup. The visco can ignite dextrinated azide. The conclusion for me is if I'd use DDNP, it would be at least a few grams in 30.06 case for example with neck sealed well with epoxy, reaching beyond where the bullet seats. Otherwise I wouldn't consider the cap reliable enough to trust it expensive material. Witch is most effective primary: MF, SADS or DDNP?
I wonder how one detonates cast TNP? 40g caseless RDX booster or 20g maximum density tamped NG/NC 96/6 in a cavity at direct contact?

Hennig Brand - 6-2-2014 at 12:44

Thanks, I used a bit of your routine of hand pressing the last bit of secondary for increased sensitivity. The hole through the reinforcing cap is only 1/16", so I put a little black powder on top just to make sure there was lots of fire ensuring ignition. DDNP behaves more like mercury fulminate, than lead azide, but according to all the literature I have seen it is much more powerful. So far I personally prefer lead azide over DDNP, but DDNP is made from picric acid and it also has some other qualities that actually make it superior to lead azide in some respects. Being able to make a primary from your secondary is very advantageous, especially when that secondary can be made from so many different things and is already so versatile as an explosive. It really isn't all that hard to make DDNP either. Once you have a good reducing agent, the processes involved are actually pretty straight forward. I know if done right it takes much less than a gram of DDNP to initiate picric acid, but even using a gram it's still a decent setup for the hobbyist. Also, I wouldn't mind storing a DDNP-picric acid compound cap for long lengths of time. However, I wouldn't want to store a cap with a peroxide primary for very long at all.


[Edited on 6-2-2014 by Hennig Brand]

Ral123 - 6-2-2014 at 13:54

People bash lead azide's ~1500j/g. It's got more energy density and initiating power then almost all the common primaries(unless you can make trinitrotriazidobenzene?). It also decomposes to pure nitrogen and lead, so it's got absolutely flat decomposition curve(I suppose) and is so bad ass, it doesn't give a s*it about confinement. The undextrinated form seems very flame sensitive.
For me it's hard to trust DDNP more then well designed AP compound cap. I've had about two failures with AP - TNP in a straw and moist UN.
Do you have a convenient way to share your DDNP recipe?

Hennig Brand - 6-2-2014 at 14:13

I love lead azide. I think in many ways it's the king of the primaries. In the "picramic acid from picric" thread I just recently gave a brief description of my process. From picramic acid to DDNP, I just used the process right out of the text "The Chemistry of Powder and Explosives". There are a few steps to the whole process, starting from picric acid, but none of them are particularly hard or time consuming. Getting a decent reducing agent is the only difficult part. Maybe you could get access to sodium or ammonium sulfide. Compared to acetone peroxide everything is hard, so I guess it's all relative.

I think DDNP is very reliable, going on what is published in the literature. What was happening during my earlier tests was simply because there wasn't enough primary used. It can take a considerable amount to get up to full velocity, given that DDNP is a DDT (deflagration to detonation transition) primary explosive rather than a practically instantaneously detonating primary explosive, or as Rosco would say "unequivocal" primary explosive. When using 0.5g in the configuration I was using it either wasn't up to high velocity, or there wasn't enough primary left after it had gotten up to high velocity, to do the job of initiating picric acid. I would have to do more testing, but I imagine the amount of DDNP needed is actually closer to 0.5g than 1g. As an example, let’s say 0.3g is burned up getting the DDNP up to high velocity, well, that would mean that when using 0.5g only 0.2g is remaining to perform at high velocity and do the initiating. If 1g is used, that leaves 0.7g left to perform at high velocity. This is just an example, but it is likely something similar that is happening.

A reinforcing cap adds confinement which is meant to help these DDT type primaries get up to high velocity quicker, leaving more material to function at high velocity, thereby reducing the amount of primary needed.

[Edited on 7-2-2014 by Hennig Brand]

Rosco Bodine - 7-2-2014 at 11:00

You are gaining understanding. The literature figures tend to be a "best case scenario" about bare minimum quantities used under highly engineered test conditions. Your own results are likely going to vary by a multiplier that may even be a different order of magnitude which will appear that the literature is off by a decimal place. I have even laughed and thought this must be a misprint or an error by the typesetter for the older print literature. Look at their figures and then compare with your tests, and believe your own tests.

Don't underestimate the value of a fast DDT low order detonating flash igniter as first fire particularly for an unreenforced cap. That is an established technique that has been reported being observed has value, from the early literature and it has followed even to being included in modern devices, because it works well in those applications where a loose flash charge is permissable. Something like one of the 3 flash igniters based on basic lead picrate or loose lead styphnate or other similar flash charge that does low order detonate is what is needed and gunpowder doesn't have that intensity. In some cases like for the DDNP a progressive loading from dense to loose could be of benefit, where the same effect is provided from the one material.

One thing you could try WRT to the stepped loading of the base charge. Above the pressed 1.5 gram of picric acid, load a moderately pressed increment of 1/3 to 1/2 gram styphnic acid, which should initiate about 20% more easily and serve also to initiate the more highly compressed picric acid below.

It may also be that a similar arrangement where the diazo derivative of styphnic acid can also serve as an initiator of styphnic acid, and the greater sensitivity of styphnic acid along with the greater initiating power for some of the diazo derivatives may be even easier to achieve than is possible with the picric acid diazo derivative used for initiating picric acid. The same general theory may apply and be more easily implemented for styphnic acid.

See these links for the styphnic acid derived analogue of DDNP, hydroxy DDNP

http://www.sciencemadness.org/talk/viewthread.php?tid=433&am...

credit to dave321 for pointing out the relevant patent US4246052
http://www.sciencemadness.org/talk/viewthread.php?tid=433&am...

[Edited on 8-2-2014 by Rosco Bodine]

Ral123 - 7-2-2014 at 11:26

Do you recommend ball milled KClO4/activated charcoal as flash igniter? It looks very stable with good flame sensitivity, but it's slow mixture. Is it a good choice for flash igniter of lead azide? Also, in AP cap, we may want isolate the AP from the fuze by leaving it sealed and use the flash igniter to penetrate the seal.

Rosco Bodine - 7-2-2014 at 12:04

No I do not recommend that as an alternative. No it is not a good choice for a flash igniter. I specified what is and will try to find a link for the 3 basic flash igniters. Basic lead picrate is the first, lead nitrato-bis basic lead picrate is the second, and basic lead picrate - lead nitrate - lead chlorate triple salt / clathrate is the third.

Here is a link for a post with all three of the basic lead picrate type flash igniters. Other compunds may work as well but are not pyrotechnic mixtures. Some specialized pyrotechnics could possibly work but that would be less likely than chemical compounds that have the properties required.
http://www.sciencemadness.org/talk/viewthread.php?tid=389&am...

Lead salts have a disadvantage of toxicity, but that is offset by a desirable physical property involving the density of the lead atom that is beneficial in transfer of energy of the exploding material and dense vapors and also allows for a more compact charge since the salts of lead tend to have high bulk density. A dense vapor containing atomized lead and travelling at supersonic velocity has more kinetic energy when impacting a target material than does the vapor of an organic material travelling at a similar velocity. So the lead compounds that are energetic may pack a greater punch originating from a smaller more compact charge, than is possible from another similar compound having a different cation that is an atom less dense than lead.

The only success I had with an AP cap I already reported was using AP putty for a first fire and there was no isolation or blow through partition or flash igniter but it was a ball of AP putty ignited directly by the fuse that worked.
Likely other configurations can work but I am not going to explore designs of detonators based upon AP. I was simply reporting an experiment that showed it can occur that AP will detonate picric acid under certain conditions. Inferences about that can be drawn and applied to other scenarios involving other materials but I really don't want to explore all the nuances of various possible improvisations using AP. Anybody who wants to delve into that kind of interest is welcome to go there but I am not going to go there because AP does not interest me as having practical value beyond being a curiosity having short term improvisational use similar to HMTD. The properties of AP make it unsuitable except for a very limited kind of niche application that is not my interest.

[Edited on 7-2-2014 by Rosco Bodine]

Hennig Brand - 7-2-2014 at 14:00

Thanks, between your posts and the text "Primary Explosives" by Matyas, I am starting to understand this initiation business a little better.

The only things in the detonator capsule above were picric acid and DDNP. The black powder was placed on the outside surface of the reinforcing cap just to insure a good flash at the end of the fuse so that the DDNP would be reliably lit through the small 1/16" touch hole in the reinforcing cap. DDNP is very easily lit, so a flash igniter is not needed in that respect, but you could be right about the other benefits of using a good flash igniter.

roXefeller - 7-2-2014 at 14:44

Quote: Originally posted by Hennig Brand  
I am starting to understand this initiation business a little better.

I think we can all thank the complexity of initiators that kept most people with simple binary base charges away from the initiators they needed most of all. It probably save me from myself when I was a kid, and does still. A person has to reach a level of understanding like you guys are demonstrating, before doing more. Obviously exceptions are too be found, but simple caps and simple base charges would make for an unpleasant world.

Hennig Brand, I saw your attempts at basic lead picrate that were linked above, from last year and before. But you've also used some as a first fire recently. Any update on your methods to overcome the hurdles for basic lead picrate synthesis?

[Edited on 8-2-2014 by roXefeller]

Ral123 - 8-2-2014 at 00:15

What complexity? It's just that we're enthusiastic to make cool things. Most people use HMTD in paper tube or AP in syringes. SADS in a straw, taped together with ETN in another straw.
http://www.inertproducts.com/inc/sdetail/250/8687
I wonder if AAA batteries make good cases.

Hennig Brand - 8-2-2014 at 01:53

Quote: Originally posted by roXefeller  

Hennig Brand, I saw your attempts at basic lead picrate that were linked above, from last year and before. But you've also used some as a first fire recently. Any update on your methods to overcome the hurdles for basic lead picrate synthesis?


If you go to page 4 of the azo-clathrate thread, you will see that with high certainty I was getting basic lead picrate. The lighter color of my basic lead picrate, compared to some samples, was the result of smaller crystal size. A very good example of this is DDNP actually. Grow DDNP crystals large and the material can be a very dark brown. Keep the crystals very small and the material is closer to a yellow color.

Something to keep in mind, according to "Primary Explosives" by Matyas lead picrate forms several basic salts with varying lead content. There are other, older, references stating the same also. The amount and quality of reactants as well as the process used were very carefully controlled for my experiments (especially the later ones), which was a strong indication that crystal size was the reason for the difference in color. Reasonably high yields were also obtained. Microscope pictures of the basic lead picrate are also shown, in the azo-clathrate thread, showing well formed crystals of uniform type.

In general my fine crystalline basic lead picrate did not detonate unconfined in small quantity when lit, however even extremely weak confinement would cause it to detonate when lit. As an example, a small sample wrapped in a single fold of filter paper would detonate when lit. The darker colored samples with larger crystals would detonate, with less or even no confinement, in small quantity when lit however.

[Edited on 8-2-2014 by Hennig Brand]

Rosco Bodine - 8-2-2014 at 09:33

When you drop a test sample amount below the critical mass minimum for self confinement of loose crystals, governed by the conditions, then ignition will not provide a DDT to low order detonation. Likewise if you pour the loose crystals into incrementally decreased diameter holes bored in a wood block, a critical diameter will be found below which the loose crystals will only deflagrate without making transition to low order detonation showing the two factors combined at work which are interactive and are critical diameter and critical mass and additionally confinement of a one open ended tube for that particular test. But simply for a mound of loose crystals on a paper plate touched by a glowing splint, at a certain weight there will be a DDT to low order detonation for all three of the flash igniters, including basic lead picrate and it is probably lowest in its vigor for self confining DDT of loose crystals meaning the critical mass minimum trends higher than example for the chlorate containing or nitrate containing complex salts. Lead styphnate also has a low critical mass for loose crystals making the DDT to low order and if further several grams excess lead styphnate is present in the 4-5 gram range for example it will accellerate to high order and show its full potential.

critical mass and critical diameter and confinement and bulk density and crystal form and crystal mesh size are all interactive parameters .......which makes things get complicated fast for testing and comparing one sample with another. If any parameter is different it will skew the test results for sample A versus sample B and for different tests using any variation on the test conditions involving any even slight change of even one parameter. There is a precision involved about every tiny detail and aspect where even temperature and humidity can have bearing.

Perhaps it is time for a little music to go along with my sample X amount of candidate energetic test compound y.....

......It just won't pop blues :P


<iframe sandbox width="640" height="480" src="//www.youtube.com/embed/3EVBhtkwszk?rel=0" frameborder="0" allowfullscreen></iframe>

[Edited on 8-2-2014 by Rosco Bodine]

Hennig Brand - 8-2-2014 at 12:08

Yeah, I could have actually measured the amount of BLP lit unconfined from the above post I guess. It was more of a rough qualitative test. LS really does take very little to self confine and DDT.

Something else from chapter two of "Primary Explosives" by Matyas; "Both DDNP and LA show a performance relatively independent of specific surface with the best performance around 4,000 cm2/g. The behaviour of MF is however quite different, as its minimal necessary amount continually increases with increasing specific surface (decreasing crystal size)."

There are several lovely graphs, illustrating the concept, before the above statement was made in the text. The graph relating to DDNP is attached as a jpg below. From the graph it can be seen that even for very fluffy material, once compressed, performance is not dissimilar from much coarser material.

So, in the case of DDNP maybe all that time spent recrystallizing is for limited benefit.

DDNP Initiator Efficiency Versus Particle Size.jpg - 73kB

[Edited on 8-2-2014 by Hennig Brand]

Rosco Bodine - 8-2-2014 at 13:03

DDNP has properties which make it behave in peculiar ways that may cause undesired but foreseeable issues which are however not insurmountable. Used alone as an initiator it can be more difficult to achieve the performance desired for DDNP than is true for mixtures that have been found to provide improved performance. But used as a single substance, neat DDNP is sensitive to crystal form and density and to loading density, and of course to critical diameter and confinement, and those factors must be taken into account. DDNP presents a situation where used alone it is somewhat marginal as an initiator. Yet certain optimized implementations using it can be workable and reliable. The navy has used detonators that were standardized but used significant loadings of the DDNP to initiate a base charge of progressive density loaded PETN, and used the DDNP as a chlorate enhanced and sensitized mixture 75/25 at a large diameter of nearly 3/8" with a DDNP loading of about 3/4 gram. So it is easily seen how a gram of DDNP for a far less sensitive base charge like picric acid is not surprising. Instead of being too impressed by R&D figures reported for a substance that is being "sold" by its inventors and investors, trust that the navy was reporting a more pragmatic approach to real world use of the technology in the field that is the theory reduced to actual practice, and that required a generous multiplier for the laboratory test results.

Urbanski reported quote:

"In Smolenski and Plucinski's opinion dinitrodiazophenol alone is not suitable as an initiating material for detonators since it requires too long a path for burning to change into detonation, hence it is necessary to add another initiating substance e.g. lead azide. Nevertheless it is suitable for filling caps."

Special techniques are required for practical use of DDNP.



Attachment: Pages from Vol. 4 D(cont.).pdf (161kB)
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Hennig Brand - 8-2-2014 at 13:12

Lead azide and DDNP are apparently incompatible, but yeah giving it a little jump start from a lead azide type explosive would solve the biggest problem with DDNP.

Rosco Bodine - 8-2-2014 at 14:02

I read about that incompatability also and wondered if silver azide would be better.

There is a chart which I have been trying to locate and I think it is in PATR which shows the initiating power of mixtures of lead azide and lead styphnate. I know the chart is also in the Matyas book, but there is an older black and white chart I'm sure I have somewhere and wanted the different context article that goes with the chart. Such binary mixtures for initiators are not uncommon. Anyway I have seen it stated also that lead azide is not compatible with lead styphnate but I do not believe that is true because of the ASA composition widely used.

[Edited on 8-2-2014 by Rosco Bodine]

roXefeller - 8-2-2014 at 15:07

Quote: Originally posted by Hennig Brand  
Both DDNP and LA show a performance relatively independent of specific surface


Taking note of that same graph, there is a strong sensitivity of the minimum amount with the density of packing, small density changes produces large drops in performance. And given a material with high specific area, in order to acheive that higher density by pressure alone will confirm the optimal packing pressure shown by your earlier graph (https://www.sciencemadness.org/whisper/viewthread.php?tid=43...). It confirms too much pressure causing reduced performance.

Rosco Bodine - 8-2-2014 at 20:36

Factors Affecting Initiating Efficiency of Detonators

R. L. Grant , J. E. Tiffany
Ind. Eng. Chem., 1945, 37 (7), pp 661–666
DOI: 10.1021/ie50427a017
Publication Date: July 1945



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