Spontaneous Transformation of TATP to DADP Using Certain Acid Catalysts

[megalomania]

The current April 2008 issue of Propellants, Explosives, Pyrotechnics has an article concerning a study that shows triacetone triperoxide (TATP) transforms to diacetone diperoxide (DADP) if the acid catalyst used is sulfuric acid, perchloric acid, or methanesulfonic acid. This transformation does not happen if hydrochloric acid, nitric acid, or tin(IV) chloride is used as the acid catalyst.

This transformation is spontaneous and it is quite rapid depending on the temperature of storage and the amount of catalyst used. Apparently this transformation continues until complete conversion to DADP is achieved. The primary method in the literature (Picatinny Arsenal method) recommends sulfuric acid as the catalyst. In light of this research sulfuric acid should not be used to prepare acetone peroxide, but rather hydrochloric acid would be the most readily available alternative. Many people already use hydrochloric in their synthesis. Furthermore, this article clearly serves as another reason why acetone peroxide SHOULD NEVER BE STORED FOR LONG PERIODS OF TIME!

Clearly this transformation is related to the presence of residual acid catalyst in the finished product. Triacetone triperoxide purified by recrystallization did not transform to diacetone diperoxide. TATP stored at 0 C still transformed to DADP, and the higher the temperature the faster the transformation.

Source:
Study of TATP: Spontaneous Transformation of TATP to DADP
Propellants, Explosives, Pyrotechnics, Volume 33, issue 2 (April 2008), p. 89 – 91
Matyas, Robert; Pachman, Jiri; Ang, How-Ghee

[-=HeX=-]

Thank you for that data! I had believed, along with many others here, that the catalyst did not affect the formation of trimer or dimeric forms. However many of us, myself included used hydrochloric acid for the catalyst simply because of a lower reaction temperature.

I wonder why this occurs? Was a reaction equation included in the article? Is it simply 2 trimer molecules being decomposed to 2 dimer molecules in the prescence of certain acid catalysts? Why do only certain acids cause this change?

I will have to have a good search because this is worrying for those who store their TCAP. Only yesterday I had to dispose of a sample vial of TCAP, which had been lying under my bed for 4 months! It had formed huge crystals, and when I threw it into the stream it hit a rock and detonated! It was the sample from my tests wade with nail polish remover. Needless to say, I was scared by the incident.

[Ethyl]

This is very interesting.

Fortunately I always use HCl for my AP.

I did once try to make AP with battery acid instead of hydrochloric acid. The strange thing was that the AP formed much more slowly and the yield was lower.

And disposing explosives by throwing them in a river is not a smart thing to do. Fortunately it went off. Imagine if it didn't and later someone found it and it went off then. I know the chances for that to happen are low but still.

[Enkidu]

Study of TATP: Spontaneous Transformation of TATP to DADP
Propellants, Explosives, Pyrotechnics, Volume 33, issue 2 (April 2008), p. 89 – 91
Matyas, Robert; Pachman, Jiri; Ang, How-Ghee

[Masonjar Chemist]

I wonder if this also accounts for AP's ability to sublime. As one trimmer molecule transforms to a dimmer, it gives a monomer that either leaves in a vapour state, or meets up with another monomer and recrystallizes as a dimmer on some other surface. Is this plausible at all? I ask because I have never experienced any loss of AP due to sublimation even over a long period when I use HCl.

EDIT: Personally, I wash and neutralize my AP with bicarbonate. Then I dissolve it with methanol and neutralize it again while in solution, and after recrystallizing I give it a final wash with distilled water. I have a much more stable product than most members describe on here with no volatility or crystal growth even after 6 months.

[megalomania]

As you can see, the article is only a brief communication, and it does not explain why this happens, only that it does.

I would suspect that those of you who do not wash and purify your acetone peroxide as rigorous as the professional scientists will experience transformation from TATP to DADP, even if you use hydrochloric acid. How many honestly follow the procedures outlined in the literature?

[ETCS (Ret)]

Well now, this knowledge answers some questions!

Since I've been using Sulfuric Acid for my experiments I've probably been dealing with DADP rather than the much desired TATP.

The last quantity precipitated and collected was about a heaping tablespoon.

After verifying that it had potency, the remainder was left in an open plastic bowl exposed to room temperature. After approximately two to three months it had apparently decomposed into an inert material which still had what appeared to be the same bulk as the original product. When subjected to flame it simply "glowed" with incandescence rather than deflagrating.

I wish now I'd kept it. I suppose I'll have to make another small experiment using HCl to evaluate the process again. I'm very curious to know what the inert material might have been.

Have any others had a similar experience?

[Masonjar Chemist]

Have any others had a similar experience?

I have once, with a batch I made with sulfuric that I failed to properly neutralized for a few days. Before I neutralized/recrystallized it deflagrated just fine, like ordinary AP, but after neutralization with an ammonia solution it was completely inert. I'm not sure if the chemicals used or the conditions I mentioned were the exact reason or if it was a coincidence, but this was the only time I had ever used ammonia and the only time I ever experienced it.

[Ethyl]

It also once happened to me. I made AP with HCl and H2O2 30% and neutralized it very well with NaHCO3 and then washed it with water. After a week or two (It was a long time ago so I don't remember correctly, the AP was staying on a table uncovered) I tried to ignite a small amount and it didn't burn at all. It was very strange as I have made AP with the same method many times and this was the only time it happened (I had some AP which was one month old stored in a test tube covered with plastic foil and it still burned like it should, but that one was made with 6% H2O2 but that shouldn't make any difference).

[Nitrato]

first of all: V-E-R-Y interesting thread!!!

Just to add to this: I always made my AP with battery acid and never had any apparent modification in my AP, even when I stored it for two months (it is quite rare when I do this..I tend to burn/detonate all within one week , at most), although this sample sublimed quite a lot (since it was left at open, on paper).
However I always recrystallized the 'washed' AP in ethanol , with a small amount of NaHCO3 added..

Here the usual HCl sold to people is only 9.5-10%; I tried many times to use it in AP synth but always get nothing (since I was using 3% H2O2 and nail polish remover.. HMTD very thoroughly washed is much safe and more powerful than AP, as all of you know).

Mega and Enkidu thank you guys very much for this info. I always believed that H2SO4 was 'king' as catalyst.

[Lewis]

first of all: V-E-R-Y interesting thread!!!
Just to add to this: I always made my AP with battery acid and never had any apparent modification in my AP,

Then again, you never prepared AP with another acid catalyst, so you don't have much to compare it to.

By the way, HMTD being more useful/safer than AP has not been accepted as fact around here. Personally, if I had to choose between two unstable peroxides that could kill me, I would choose the cheaper one. (AP)

[Nitrato]

Lewis,

Thank you to see this point in my post. I did not was very thorough in my earlier post, that was my lack. Sorry.

I actually made before, some AP from dilute HCl and acetone (but of course using 39% H2O2..). But I made this way only one time and this was a a couple of years ago. And since I used all AP quickly after made, really I cant compare both ways, especially in storage behaviour. If I recall correctly, the burn test from that fresh product of HCl batch was not very different of my usual H2SO4 batches.. But as you can see, that statement is far from being of any significative accuracy and importance to this discussion.

The reason , I think, that never worked with 3% H2O2 stuff is that the reactants were very diluted. Acetone sold to commom people here (acetone nail polish remover), by local law, cant be more concentraded than 60% acetone (the rest is a mix of ethanol, water , dyes , heavy oils and other shits) ; HCl only 9.5-10%....And as spected is just a PITA when one uses this for AP synthesis.

So the only way I found to this procedure work was to carefully boil down the 3% H2O2 to about half its volume. This way I managed not only to made AP in better yields ( just apparent better yieds, since some of the H2O2 certainly decomposed) but HMTD as well.

But Today , fortunately, I dont need to do this, because of the more concentrated H2O2 that I have (I just bought that stuff, without any question or the like :) )

BTW, I also agree with you that organic peroxides are not that good by being too unstable and for related storability problems, but just easy to make and CHEAP. So I almost always use that explosives, just for being cheap, powerful and quickly made without major problems.

I personally prefer HMTD since it just always worked fine for me and although it is much more expensible than AP, it works better, IMHO (very fine powder, much easier to compress and relatively safer than AP, etc).

BTW, regarding storability problems and other primary HE's, just for comparison, I have stored in my attic , for 5 years, a small sample of Ag2C2*AgNO3 under absolute ethanol that still work fine and looks like in the day that was made and that I rarely use (I used once when bored to make more HMTD). But of course I will destroy that before that stuff do it the other way :(

Back on topic:

Another reason that I found this thread very interesting was due the fact that the amateur explo/pyro community (and I, of course) where I live always believed that sulfuric acid was the *best* choice. Not only the OTC form (~30%) is relatively stronger (comparing with dilute HCl) to use but almost cheap as HCl.

I always followed the Mega's procedure (that uses H2SO4) but with a bit of modification, since the concentration of my reactants were not the preferred in his page.

[megalomania]

The procedure on my website, and the procedure often cited in the literature, is the Picitanny Arsenal procedure, which is presumably the best method around. It has only been in the last ten years or so, due to acetone peroxide being used in an increasing number of improvised devices, that the compound has been researched at the level of commercial explosives.

Since it was “decided” decades ago that acetone peroxide is worthless as a military or commercial explosive, academic evaluation of it ceased, or slowed down near enough. Now that there is a crapload of money being thrown into Homeland Security and anything defense related, I would expect research into acetone peroxide to increase more than it already has. Not necessarily the synthesis, but testing and evaluation.

I would also not be surprised if there is legislation that restricts the sale of either hydrogen peroxide or acetone, or both, in the near future. Such laws will largely be to assuage the sheeple in government, they will want action to purge society of this scourge of demon chemicals that has been sitting on their children’s shelves for lo these many decades.

Taking away these chemicals won’t stop the terrorists, but it will hurt us, the innocent experimenters. The terrorist bombings to date have all been in foreign countries, so US chemical legislation won’t help there, and the terrorists use industrial chemical supplies, which legislation is unlikely to touch.

[SafetyLast]

I've been making AP for about 8 years and have always used HCl.
I think it was ~Lowry who suggested early on that HCl should be used.
Using HCl over H2SO4 makes sense as it usually costs less and is more readily available for most people.