Sciencemadness Discussion Board

The next wave of IEDs

killswitch - 11-8-2013 at 09:17

Restrictions on explosives have come a long way since the Bath School disaster and Greenwich Village townhouse explosion. No longer can dynamite and blasting caps be purchased through mail-order catalogs.

However, news reports from all around the world every single day bring home just how determined terrorists and guerilla fighters are to produce explosives with even the most limited precursors.

Now, TATP, once nothing more than an academic curiosity and laboratory hazard, is out of the bag as an easily-produced replacement for traditional blasting caps, and terrorists will not be deterred by the insane dangers of peroxides.

Fortunately, due to TATP's high vapor pressure and advances in chemical sensing, explosive detection devices are now just as capable of detecting it as they are at traditional nitro compounds. HMTD also contains peroxide groups and has a non-negligible vapor pressure. Detecting it is merely a question of increasing sensitivity while using computer algorithms to screen out noise, and I suspect that has already been done.

However, terrorists have become more and more desperate as time goes by. In the Bali nightclub bombings, the terrorists used over 1000 kg of aluminum/sulfur/KClO3 flash powder. The sensitivity of Al/S/KClO3 has given it the moniker "death mix" for a reason.

Unlike in India and Indonesia, acquiring sufficient materials for a metric ton of flash powder is much, much more difficult in the United States, United Kingdom, and Canada, given the decreased proximity to the pyrotechnic paradise that is gray-market China. Also, the previous use of this mixture has alerted law enforcement to the dangers.

Here now, we should consider other, as-yet unused substances, their properties (including sensitivity, power, and ease of precursor procurement), and how to improve the ability of detection equipment to sense them.

Let us keep in mind that we are dealing with individuals to whom a metric ton of flash powder or TATP as a main charge does not seem unreasonable. If it is stable enough to move (this rules out NI3 and organic perchlorates), it is of possible concern. If it is cheap and simple enough to be somewhat competitive with fertilizer or Tannerite (this rules out octanitrocubane and most fused-ring nitrogen heterocycles), it is of further concern.

Two substances jump out at me. Since I have never synthesized them and cannot find good summaries of their more esoteric properties such as vapor pressures, detonation velocities, and detonation pressures, I am not sure how viable they might be, but they concern me for their ease of synthesis and the availability of the precursors.

These are 1,3,5-trichlorohexahydrotriazine and dinitrogen tetrasulfide.

TCHTZ requires only hexamine, sodium hypochlorite, and ethanoic acid. It is insoluble in water and readily purified by washing. It is soluble in methanol and could presumably be recrystallized from that substance for higher purity and density. However, the ease of synthesis (dissolve a thing in a thing and mix two other things, then mix it all together, stir, filter, and wash) may make the extra purity from a methanolic recrystallization unnecessary. It may not even be necessary to remove the trioxane from the tablet. I simply don't know enough about this compound to be certain.

Is it more sensitive than HMTD or less? As a chloramine it is probably going to hydrolyze at some point, and excluding water is harder than excluding metal. But it is certainly a cheaper and more easily scalable synthesis, and the compound is a relative unknown in law enforcement circles. Detection schemes may need to be updated to focus on nitrogen-chlorine bonds as well as nitrogen-oxygen bonds.


The second compound of note is tetranitrogen tetrasulfide.
This is a primary explosive and thus we wouldn't think of using it in a main charge. Unfortunately not everyone thinks that way.
Tetranitrogen tetrasulfide is more difficult to make than TCHTZ, but is also among the least likely to be detected by current technology, given the unusual nature of the compound.
It is also relatively cheap, requiring only sulfur, chlorine, ammonia, and an aromatic liquid hydrocarbon such as xylene as a solvent. In places where hexamine is difficult to find (perhaps where everyone uses Sterno for camping fuel), nitrogen sulfides are an alternative that is essentially impossible to preclude via controls on precursor chemicals.

So, how dangerous are these materials? Can they provide the same explosive power as peroxides, flash powders, and Sprengels? Can detection schemes be modified to include them? Are large charges utilizing them possible? Because at least in the case of tetranitrogen tetrasulfide, limiting the precursors is simply beyond the realm of possibility.

And are there any others I have overlooked?

[Edited on 11-8-2013 by killswitch]

franklyn - 11-8-2013 at 10:25

" Greenwich Village townhouse explosion "
You actually remember that ? Dustin Hoffman lived right next door.

" explosive detection devices are now just as capable of detecting "
A dog's nose is so far the best detector.

" Unlike in India and Indonesia, acquiring sufficient materials for a metric ton
of flash powder is much, much more difficult "
In countries which have the tradtion of making your own in home cottage
manufacturing is the one source that cannot be stopped "

" are there any others I have overlooked ? "
Electric exploding wire is the choice substitute for initiating detonating explosives.
For a main charge there are no limitations axcept cost.

.

Fantasma4500 - 11-8-2013 at 10:43

i cant say about bali, i havent heard much discussed about it, so i suppose it was legit, who knows.
anyhow, i know people on this forum arent much for talking about explosive devices
by looking at the pressure cooker device seen going off near the end line at boston, i just .. i just dont think the smoke is legit for 'gunpowder'
knowing the background of the act, i just doubt they would use anything as unprofessional as gunpowder, with the list of stuff they have access to

to me it looked far too white to be gunpowder
anyways, i dont think you should be very worried about these socalled terrorists, they probably tried, but they never succeeded getting in the western world, perhaps in europe, i cant say, but all you hear from usa about terrorists; is bullshit.
feel free to look it up from another angle of view, you shouldnt believe anything thats just implied

pretty interesting they were capable of having 1 tonne of that mixture although..

Dany - 11-8-2013 at 11:19

If the person who is attempting fabricating bomb is knowledgeable in energetic materials he won't think of synthesizing N2S4 and 1,3,5-trichlorohexahydrotriazine for the following reason:

N2S4 and trichlorohexahydrotriazine are very unstable (more unstable than TATP) so scaling up the synthesis to several Kg is difficult because of the yield obtained in each reaction (yield are sensitive to material used, purity, quantity being used...). separation of the synthesized product is another problem and pose serious hazard to the operator. These two explosive will not substitute for example KClO3 based explosive for several reason: if the operator is able to buy sodium hypochlorite for the synthesis of trichlorohexahydrotriazine this mean he can make NaClO3 (or KClO3) easily and without great danger. fuel for chlorate explosive is also available in big quantity like sugar (the situation change if the goverment ban sugar...) aluminium powder which can be an impoortant component of IED can be readly made of aluminium foil. also, you can rapidly mix the ingredient of chlorate explosive and use them without passing through many tedious step of organic synthesis of trichlorohexahydrotriazine or N2S4. And just for information:

every energetic compond has what we call a critical mass which can be calculated for a particular geometry using thermal analysis data. above this critical mass the explosive will self-heat to reach to ignition temperature and detonate due to self confinement. for example mercury fulminate mass is represented by a cube having an edge of 1 meter lond, while TNT a far more stable EM than mercury fulminate has a critical mass represented by a sphere having a diameter of 1 Km! i think based on the structure of N2S4 and trichlorohexahydrotriazine (N-Cl bond are very weak) the critical mass of these EM is small which lead to spontaneous explosion if synthesized in Kg quantity.

And for franklyn, i don't think that the only problem of an exploding wire is the cost. you cannot simply make a wire to really detonate. Even detonator fabricated for this purpose (Exploding Bridge Wire Detonator) need complicated electric circuit and the bridge wire is in contact with secondary explosive like PETN or a PBX based explosive for reliable initiation of the main charge.

One of the explosive that may be used (but also not simple to handling by terrorist is the simplest liquid explosive : nitric oxide (NO).

nitric oxide is capable of detonating in its all physical state. In liquide state the measured detonation velocity is 5300 m/s. the predicted detonation pressure is 103 kbar. not a very powerfull explosive but it will do the work.

for theoretical detonation performance of NO see J. Phys. D: Appl. Phys. 28 (1995) 665-669.

for measured detonation performance check this paper:

Ribovich, J., Murphy, J. and Watson, R. Journal of Hazardous Materials, 1975177, 1, 275-281.

Dany.

APO - 21-9-2013 at 16:54

Quote: Originally posted by killswitch  
However, terrorists have become more and more desperate as time goes by. In the Bali nightclub bombings, the terrorists used over 1000 kg of aluminum/sulfur/KClO3 flash powder. The sensitivity of Al/S/KClO3 has given it the moniker "death mix" for a reason. [Edited on 11-8-2013 by killswitch]


According to Wikipedia, " the terrorists assembled 12 plastic filing cabinets filled with explosives. The cabinets, each containing a potassium chlorate, aluminum powder, sulfur mixture with a TNT booster, was connected by 150 metres (490 ft) of PETN-filled detonating cord. Ninety-four RDX electric detonators were fitted to the TNT.", that doesn't sound to desperate to me.

Ral123 - 21-9-2013 at 23:36

MgAl is ball milled into fine powder and can explode with large variety of oxidizers. Formidable high blast/incendiary/thermobaric material.