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Author: Subject: Which is more powerful, HMTD or TATP ?
AndersHoveland
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[*] posted on 28-9-2012 at 06:45
Which is more powerful, HMTD or TATP ?


TATP has a worse oxygen balance than HMTD.

Because the molecules of TATP are bigger, one gram of TATP contains less -O-O- groups than HMTD. HMTD has a higher ratio of peroxy -O-O- groups to carbon/hydrogen atoms. I am not sure of the nitrogen atoms in HMTD help add any power. One paper seemed to suggest that the nitrogen in the decomposition products is only in the form of trimethylamine or HCN.

But a cubic centimeter of AP has a little more oxygen then a cubic centimeter of hmtd.

HMTD has a density of around 0.88-1.10 g/cm3. TATP has a density of around 1.26 g/cm3. HMTD contains about 50% oxygen by weight. TATP contains about 40% oxygen by weight. So depending on what the intial densities are (how packed), either could be more powerful than the other.

In addition, the byproducts of HMTD may potentially contain the C-N triple bond, releasing some more energy. The gaseous decomposition products of HMTD will consume less energy being vaporized than the more liquid byproducts from TATP.

TATP has a detonation velocity 5300 m/s, but may be lower around 3000 m/s if not compact.

HMTD has a detonation velocity of 4511 m/sec at 0.88 g/cm3, and 5100 m/sec at a density of 1.10 g/cm3



Chemical Stability
HMTD usually tends to degrade in storage, though this can be greatly lessened by neutralising all traces of acid in the product.
But TATP, also being an organic peroxide, is likely not completely chemically stable over long periods of storage. Hydrolysis equilibrium will be inevitible, and the peroxide could potentially decompose, or even oxidize the acetone through its enol tautomer.

In fact, acetone is actually slowly oxidized by hydrogen peroxide, this is much more rapid under alkaline conditions (bicarbonate). "The Journal of biological chemistry", Volume 35, (1918), p90-91


Detonation Decomposition Products from Acetone Peroxide

"Calculations from Keinan, professor of chemistry at Haifa Technion, Israel, predict is that TATP undergoes anentropic explosion, each molecule of TATP collapsing to produce three molecules of acetone and one of ozone. 'A supersonically propagated entropy burst drives the explosive power of TATP, not the usual heat generated during the decomposition of conventional explosives,' he concluded."

So if this were correct, in actual practice, nearly all of the gas released would be oxygen.

I am not sure how long the ozone sits around after the explosion, because it would be expected to slowly oxidize the acetone (similar to the reaction involving the oxidation of acetone by halogens, which proceeds through the enol tautomer). The initial oxidation of acetone by ozone would produce hydroxyacetone. However, one study describes the oxidation of acetone by ozone using manganese oxide as a catalyst.

"Although TATP doesburn when it is set alight, releasing large volumes of carbon dioxide and water, itappears that very little heat is created when it explosively decomposes,' said Keinan."

The heat of explosion for another organic peroxide, known as DPPP, is suppossedly only around 200 degC.

The reason acetone peroxide does not undergo combustion during detonation is because the oxygen balance, relative to fuel, is so poor, and the explosion temperature is relatively low.

The autoignition temperature (in air) for acetone is 465 °C, a value which is probably only a little higher than the explosion temperature for acetone peroxide. The decomposition products from the entropic detonation would, in any case, rapidly cool as they expanded.

So while one idea is that the main decomposition products from TATP are acetone and diatomic oxygen gas (O2), an actual investigation showed very different results.

It suggests that the decomposition product is mostly CO2 rather than O2. Only trace quantities of ozone are formed. Methyl acetate, ethane, and carbon dioxide were also detected in lesser quantities.

The thermal decomposition, at 151 °C, of each mole of the trimer yields about 2 moles of acetone, when the acetone peroxide was in the gas phase, and about 2.5-2.6 moles of acetone when the acetone was in the solid form. Under all conditions, the principle decomposition products were acetone and carbon dioxide. Minor reaction products included ethane, methanol, and 2-butanone, which apparently resulted from reactions of intermediary methyl radicals. Ethyl acetate and acetic acid also formed.
"Decomposition of a Multi-Peroxidic Compound: Triacetone Triperoxide (TATP)", Jimmie C. Oxley, James L. Smith, Heng Chen; Propellants, Explosives, Pyrotechnics [Journal], Volume 27, Issue 4, pages 209–216, September 2002

The 2.5 mole yield mentioned in the above source would correspond to about 17 percent of the acetone in the TATP being oxidized in the decomposition.

Some idea of the explosion's reaction products might be gained from the following investigation:
The main decomposition products from triacetone peroxide in toluene solution, heated to 173 °C, were formed in the following yields, relative to the initial moles of triacetone peroxide:
acetone 85% [eighty-five]
ethyl benzene 7.2% [seven point two]
1,2-diphenylethane 154% [one hundred fifty-four]
methane, benzyl alcohol, benzaldehyde, and benzoic acid were also detected.
"Thermal Decomposition Reaction of Acetone Triperoxide in Toluene Solution", Gladys N. Eyler, Carmen M. Mateo, Elida E. Alvarez, and Adriana I. Cañizo, (Argentina)
J. Org. Chem., 2000, 65 (8), pp 2319–2321


The actual reaction does seem to be somewhat more complex, however.

1,2-diphenylethane is essentially just two toluene molecules bonded together at their methyl groups. The formation of this combined with ethyl benzene shows that some of the toluene was oxidized by the peroxide groups as they broke apart, and that the resulting toluene radicals were able to recombine. Although 85% of the resulting acetone did not further react, this quantity would no doubt be less if the decomposition had not been dissolved in toluene, which was attacked, (obviously then the TATP would be allowed to explode).

[Edited on 28-9-2012 by AndersHoveland]
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[*] posted on 28-9-2012 at 07:57


Quote: Originally posted by AndersHoveland  

But TATP, also being an organic peroxide, is likely not completely chemically stable over long periods of storage. Hydrolysis equilibrium will be inevitible, and the peroxide could potentially decompose, or even oxidize the acetone through its enol tautomer[Edited on 28-9-2012 by AndersHoveland]


But remember, in TATP there is no longer acetone that could form enol tautomer. It should be viewed as a relatively non-reactive compound (no double bonds).




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[*] posted on 28-9-2012 at 13:57


The differences between thses two peroxides are not really big but HMTD has more power and stability when it's pure. 0.75 gram HMTD has the power of a reinforced
# 10 cap. 0.5g is equivalent to a strong # 8 cap while1 gram TATP = No. 8 cap. 75 g. = No. 6 cap
source: Dirk Goldmann

[Edited on 28-9-2012 by Phantom]

[Edited on 29-9-2012 by Phantom]




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AndersHoveland
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[*] posted on 28-9-2012 at 15:16


Quote: Originally posted by Adas  

But remember, in TATP there is no longer acetone that could form enol tautomer. It should be viewed as a relatively non-reactive compound (no double bonds).

If there is even the slightest trace of water (particularly if all the acid has not been neutralised), there will inevitably be some small equilibrium, and thus potential decomposition.

This seems to be confirmed by my own experiments. After several months, a sample of solid wet acetone peroxide sealed in a vial became just a liquid. Also to note, the acid in this sample had not been neutralised.

I read somewhere in this forum a claim that HMTD is a little better as an initiator than TATP. Is this true?

[Edited on 28-9-2012 by AndersHoveland]
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[*] posted on 28-9-2012 at 23:16


Quote: Originally posted by AndersHoveland  

If there is even the slightest trace of water (particularly if all the acid has not been neutralised), there will inevitably be some small equilibrium, and thus potential decomposition.

This seems to be confirmed by my own experiments. After several months, a sample of solid wet acetone peroxide sealed in a vial became just a liquid. Also to note, the acid in this sample had not been neutralised.
[Edited on 28-9-2012 by AndersHoveland]


I really don't think that TATP can react with water in any equilibrium, but I may be wrong..
Which acid did you use? If it was H2SO4, it might have dehydrated and decomposed the TATP. And HCl is known to be oxidized to chlorine by TATP over time (tested by me).




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[*] posted on 29-9-2012 at 00:41


The concept of AP not using it's oxygen is just too naive, if you mix AP with aluminium the temperature will be enough for the aluminium to react with the CO/H2O and it'll burn like flash. It also flashes so it's not really cold. It has like 1/2 the energy of TNT.
I kinda prefer AP, I have 5 months old sample and it burns like it's brand new, it's very dry, it doesn't smell or something. I had 6 months old hmtd and it burned like it's 1/2 hexamine.
I had no problem initiating UN, picric, tetryl, hexogen, egdn and other stuff. My hmtd always had difficulty DDT. I'd do a test AP vs HMTD but I'm not sure about the quality of my HMTD.
Don't underestimate the sensitivity of HMTD, it's considerably more then fresh AP. Only problem with AP is that it sublimes. That's all.
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[*] posted on 29-9-2012 at 01:47


Quote: Originally posted by Phantom  
The differences between thses two peroxides are not really big but HMTD has more power and stability when it's pure. HMTD is much safer than TATP when it's pure and also has a greater power. 0.75 gram HMTD has the power of a reinforced
# 10 cap. 0.5g is equivalent to a strong # 8 cap while1 gram TATP = No. 8 cap. 75 g. = No. 6 cap
source: Dirk Goldmann

[Edited on 28-9-2012 by Phantom]


All of the above information is incorrect except the one fact that HMTD is more powerful than TCAP
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[*] posted on 29-9-2012 at 08:46


But why, isn't volume basis AP the more powerful? It's denser and has higher vod. With less then 1.0 density hmtd is just a cheapoo primary with a kinky name. Do you have an idea how much of the two peroxides will have the initiating ability of No8 cap then?
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[*] posted on 29-9-2012 at 09:47


It has not been confirmed by testing the full amount but the indication is there may be a high order threshold on the impulse for HMTD at around 3-4 grams range which would be comparable to a #8 ....but I would not bet the farm on that. I really don't want to discuss peroxides as the topic has pretty much been beaten to death already. Maybe I'll get back later on this but I can't spend time on this now.

[Edited on 29-9-2012 by Rosco Bodine]
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AndersHoveland
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[*] posted on 29-9-2012 at 18:15


Quote: Originally posted by Adas  

I really don't think that TATP can react with water in any equilibrium, but I may be wrong.

No, it is an equilibrium reaction. Solid acetone peroxide will eventually dissolve again if placed into excess dilute acid.

Quote: Originally posted by Adas  

Which acid did you use? If it was H2SO4, it might have dehydrated and decomposed the TATP. And HCl is known to be oxidized to chlorine by TATP over time (tested by me).

I used sodium bisulfate.
H2SO4 does not cause any real dehydration (not anymore than any other strong acid) unless it is very very concentrated.

[Edited on 30-9-2012 by AndersHoveland]
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[*] posted on 8-10-2012 at 09:56
TATP


This is my experience from yesterday about the sensitivity of TATP.
I have made various small batches of AP over the years and used them up within a few days. Well I was going to the gravel pit for the day to shoot with my friends so I made a batch using about 200 ml acetone, 35% H2O2 and 31% HCl in a 500ml container in my freezer. The filtered product, through a paper towel, was just a bit bigger than a golf ball when the water was slightly squeezed out. Since I was transporting it via gravel road with bumps etc. I didn't let the AP dry. Now I set the clump of AP on a smooth rock and backed up about 75 mts and shot at it with my .22LR scoped Ruger M77/22.
I could not believe what I saw. I had fired 3 rnds at it 2 were a direct hit and just broke the ball shape clump went through. Then I switched to my 5.56X45 and it detonated.
Dry AP always detonates when hit with a .22LR and much less .... I just couldn't imagine water would desensitize it so much.
I had thoroughly neutralized the AP by letting it sit in NaHCO3 soln for at least 24 hrs in my fridge. Besides a fine translucent layer of AP on the surface .... All my AP was under the soln and fine crystals.
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[*] posted on 29-10-2012 at 05:56


never done tatp, only hmtd...i'll leave the tatp for the durka durki-stanians. As far as stabilizing HMTD powder long term, yes, repeated washes w/ bicarb, but at the end leave a small amount of bicarb in the mix, thoroughly mixed in there, and plop in an 02 and a moisture scavenger. HMTD when lit, will make a 10 foot "Bic Lighter: flame from source. No residue.
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