Isotopic Explosives

[Al Koholic]

As many of you know, isotopes of common elements are not always radioactive. For example, 99% of the Earth's C is Carbon 12, 1% exists in the form of C 13. C 13 is not radioactive like the well known C 14.

I wish to propose this idea in a highly hypothetical manner since I know basically nothing about any specific isotopic compounds.

Suppose one were to come into a supply of C 13 or C14, and convert this carbon into lets say, benzene, and from there say... phenol.
Unlike phenol formed from C12, this phenol, while being nearly chemically identical, would be heavier by 6 g/mol of C 13 and by 12 g/mole of the C 14 derivative.

Now lets subject some C 13 phenol to nitration to form TNP. This trinitrophenol is identical in every way to regular TNP except for having a slighly higher mass and a slightly higer stability (I'll get to this). So, the molecules should pack together the same way in a composition/crystal and you would therefore have a higher density product, and a more powerful one as well.

The stability should also be higher because of Hooke's law. If one views (correctly) that a chemical bond is a lot like a spring, it can be shown that oscillations of chemical bonds involving C12 as compared to C13, are slightly faster. This is because of the higher mass of C13 and its correspondingly higher inertia. The faster a chemical bond is oscillating, the less stable the bond and the "faster" the rate of reaction in any reaction that bond participates in. This is one of the prime principles of isotopic dating in the quest to find the earliest evidence of life on this planet. The C13 participating in photosynthetic reactions is "processed" more slowly by the plant than is C12, leading to a discrepancy between biological carbon residues and the natural concentration of oxidized carbon in the atmosphere. This is due to C13 being heavier and therefore more stable in bonding.

Anyway, could the stability increase be of sufficient size that one could potentially stabilize very sensitive nitro explosives in which a C is bonded to an N? Would the effect be applicable to nitro esters like methyl nitrate?
Maybe all this is not making sense, and maybe the stability increase would be quite low, but at the very least, utilizing C13 or C14 in an explosives carbon backbone would lead to a higher density and higher power explosive compound.

Lemme know what you think.
Al

[Mr Cool]

It would be hideously expensive, but your reasoning looks sound.

[Al Koholic]

Well...yeah. Totally expensive. Expensive beyond the point of any resemblence of control over cost. However, it is an interesting theoretical thing I just thought of today on my way home from class. I wonder if there has been any research done into the topic.

[Anthony]

I don't see why it would be unimaginable expensive. It seems that C13 can be enriched from natural sources of carbon.

This company seems to be selling a lot of compounds of C13:

<a href="http://www.iconisotopes.com/c13cmpd.html" target="_blank">http://www.iconisotopes.com/c13cmpd.html</a>

[firebreether]

I would think that it might slow down the exlposive, and maybe make it less powerful, since the bonds are stabler.

Why stop at C13? You could use Deuterium instead of ordinary H, and O18 instead of O16, and N15 instead of N14. Heavy water (D2O) is a metabolic poison because it does not get processed as quickly in the body as regular water does, so i suppose it would be the same with C13 as well.

I do think its more trouble and cash then it could possibly be worth though.

[Al Koholic]

Well yeah...from a theoretical standpoint, why not use those atoms. Hell, and since this is a theoretical topic...good point.

The point to any of this type of research would be simply to compare the performance characteristics of the analogous explosives. I am highly interested in seeing if any of my predictions would be correct or incorrect.

The increased bond stability as it relates to explosive power...
That is a good question...I'm not convinced totally one way or the other what would happen. On one hand, I want to think that the increased bond stability means that the whole molecule is of lower energy and thus will not liberate as much heat on detonation. However, this depends highly on what types of isotopes are used and on the way the products form.

On the other hand, I want to believe that the explosive power will still be similar because the geometry of the analogous molecues will be identical and thus any bond tensions will be as well.

Additionally, I believe the POWER itself may not be affected at all now that I think about it. Perhaps it will meerly be exhibited in a different form. So the VoD is a little lower...the heat produced a little lower, but the energy should still be there in the form of the higher momentum of the resultant particles after the detonation. Could be these particles will have the same momentum as the regular products only will be moving slower...

Pretty fun to think about...I may have to spend some time in the library fairly soon. :)

Edit: Anthony, I didn't see any prices for those compounds listed and from what I gathered, they were being sold in .5 or 1 g quantities....something indicative of high prices. Perhaps they are not as expensive as I was thinking though and at the very least, they sure do have an incredible variety available!

Obviously this has no practical application to someone who wants to make a hole in the ground. The theoretical and experimental "fun" that something like this can offer may be worth a decent sum of money....however one that is most likely out of my meager budget!

<small>[ January 30, 2003, 12:35 AM: Message edited by: Al Koholic ]</small>

[Mr Cool]

While we're kinda on the subject, does anyone have any links to pages describing isotopic enrichment, other than for UF6? I haven't been able to find anything useful.
The one I'm specifically interested in is potassium.

Edit: <a href="http://dwb.unl.edu/Teacher/NSF/C04/C04Links/www.fwkc.com/encyclopedia/low/articles/i/i012001292f.html" target="_blank">Here's</a> some information...

<small>[ January 30, 2003, 02:30 PM: Message edited by: Mr Cool ]</small>

[Marvin]

The effect would be small, far too small to make a difference in noticable stability of a compound. Though making an explosive out of radioisotopes is on another level alltogether. I'm not convinced by the hooks law argument, but I dont remeber what the official explanation for the kinetic isotope effect is in varios circumstances.

Interestingly before the enrichment of deuterium by electrolysis was discovered, several well respected scientists showed it shouldnt happen. Quite ironically this turned out to be, and still is the most efficiant method we have (in terms of enrichment ratio), but rather expensive.

Using heavy atoms in explosives gets you a 'higher density explosive', but the energy density isnt improved. Youd get the same effect by adding lead powder to the explosive, and in these terms its more obviosly not useful.

Mr Cool, Your after K-40, I'm sure. I'm after that myself, but that high up enrichment is tricky, and it has 2 stable isotopes, one either side. That page gives a basic grounding in theoretical effects, but is rather wanting on practical methods, which often bear no resemblence.

A good way for nitrogen for example, involves taking a large vertical tube (filled with N2 gas), and stretching a fine wire down the middle. The wire is heated electrically and you get an enrichment from the top to the bottom of the tube by a combination of thermal diffusion away from the hot wire, and convection currents up and down the tube.

Ive only found one method thats been used successfully for potassium enrichment and I dont have the actual paper, only a mention of it, its not electrolysis, but it involves electrolysing a solution of a gel (to prevent mixing) in which a K salt is dissolved, exploiting the different ionic mobilities.

Another odd method chemically is currently the most cost effective deuterium enrichment method from natural water. H2S and H2O in contact can exchange hydrogen atoms fairly quickly, and at equilibrium the deuterium is enriched in one or the other (offhand I dont remeber which). This sounds quite odd at first and came as a surprise to me, that there would be a 'static' difference in the concentration of D between the phases, but it makes sense when you remeber that equilibrium isnt when it stops reacting, its when the rates of both reactions becomes the same, and thus its preferential kinetics that determine it.

It gets weirder. The partition coeffetient, a measure of the 'preference' for D/H in the relative phases actually changes noticibly with temperature, and its the difference between 2 temperatures thats actually used industrially. By having alternate hot and cold towers, with counter currents of H2S and water, overall enrichment of a small amount of water can be achieved (at the expense of the bulk, obviosly) that doesnt use up any H2S. This process is very cheap, but its actually not very good in terms of deuterium retention, only about 1 D atom in 5 in the feed water makes it to the heavy water produced by the plant. (This is the first stage in a typical plant, the economics change, so higher retention methods are used later on).

Compair this with electrolysis, in which the water remaining can have 12 times the concentration of D of the hydrogen gas produced in a well built cell (for natural water concentration). The drawback is you have to turn all the water into hydrogen and oxygen gas, and this is very expensive.

I have some alternative ideas on K-40 enrichment, but its too early to know if they would work well enough to be useful and more importantly be the cheapest/easiest to do at home. In the shorter term I'm planning on trying D enrichment at home for several reasons. Its the easiest, I want some, I want to do it myself, and I have a DIY method of measuring D concentration that doesnt require a mass spectrometer, or rely on hoplessly insensitive density measurements.

Since I'm throwing in everything except the sink, I'll add the trivia that since 'hydrogen' refers to all of its isotopes, when refering to H-1 specifically, its called protium. When I remeber, I'll add some of the internet URLs I found on practical isotope enrichment (of anything), there is very little out there that isnt too theoretical, or too shallow to be useful.

[Mr Cool]

That H2S method is interesting! I might try getting some D2O, just as an experiment. I'd use successive fractional distillations, I've heard this can be quite efficient. Sodium and phosphorous are more immediate goals though, it'd be nice to be able to produce either of these so that's what most of my experimenting time is used by at the moment (results will be posted if I find out anything new. I have high hopes for my specially designed Na producing cell, and furnace construction is due to start this weekend...).

Yes, I'm after K-40, since enrichment could easily be measured by an increase in count rate, once I process enough to measure. I was thinking along the lines of something like chromatography or electrophoresis, that sort of thing. I don't care if I get all the K-41 and a load of K-39 as well. I've seen products for sale with K-40 enriched to 4%, no higher. Maybe C-14 would be easier due to the bigger % difference in mass. I suppose if you rotted down some plants and collected the methane you could use the hot wire method, in theory. Natural gas would be too old and anything bigger than H on the C would reduce the % mass difference too much.

How are you thinking of measuring D enrichment? I can't think of anything easier than careful density measurement, this should be accurate if you process a lot.

[firebreether]

I think the easiest method for Deuterium separation for an amateur would jsut be straight distillation. The enrichment factor isnt large, and youd need a bunch of successive distillations, but it's quite simple. I think to get a decent purity you would need around 100 stages though. This was used before they used the H₂S method.

[Al Koholic]

"Using heavy atoms in explosives gets you a 'higher density explosive', but the energy density isnt improved. Youd get the same effect by adding lead powder to the explosive, and in these terms its more obviosly not useful."

True...I hadn't thought of that.

BTW, for what reason are you seeking 40K?

[Mr Cool]

Personally, just to see if I can get it, as a challenge.
It'd also make a nice high-energy (1.3MeV) beta and gamma source. 25kg of KCl contains 1.57g of K-40, producing around 400KBq. It decays by B-, B+, and electron capture, and also releases gamma rays, with a half-life of 1.28 billion years. So, 25kg of KCl produces a whopping 84nW! This is tiny, but in total it contains around 4900000000 J, equivalent to a ton of TNT!
Isn't nuclear energy amazing?!

<small>[ February 01, 2003, 10:13 AM: Message edited by: Mr Cool ]</small>