destination: fluoroacetate

[Polverone]

Fluoroacetates appear easier to make than even the simplest of the military nerve gases. They aren't as easily dispersed, but they are extremely toxic, not detected by usual analysis, and could probably be practically used in certain ways that I won't bother to speculate about here.

As I see it, there are three basic steps involved.

1) Formation of chloroacetic acid
2) Formation of methyl chloroacetate
3) Conversion of methyl chloroacetate to methyl fluoroacetate
(optional) 4) conversion of methyl fluoroacetate to sodium fluoroacetate or another nonvolatile salt.

Step 1 is rather a pain if you start from acetic acid. You bubble chlorine through acetic acid while keeping it hot, irradiated, and mixed with sulfur or phosphorus. You end up with a mixture of chloroacetic acids. Chlorine is not fun to work with, and you need to generate quite a bit.

However, the other day madscientist found a delightful tidbit of information in the Merck index: trichloroethylene, readily available OTC in the US as a solvent (and probably available elsewhere, at least for industrial use, without much trouble), is hydrolyzed by H2SO4 to chloroacetic acid. The process provides pure monochloroacetic acid. Huzzah! I found details on the reaction in Ullmann's Encyclopedia (thanks, Rhadon): industrially, TCE is hydrolyzed with 75% H2SO4 at 130-140 degrees to yield a solution of approximately 50% monochloroacetic acid, which is purified by vacuum distillation. There's a bit of a problem for the home chemist: TCE boils at 87 degrees, so the industrial reaction must be conducted under pressure. However, I assume that the reaction will take place at lower temperatures given enough time, and preliminary experiments have been encouraging. I am definitely experiencing the sharp stink of chloroacetic acid in my lab, though the H2SO4 is turning disturbingly black and chunky. Perhaps next time I'll get it right...

HCl perhaps might work in place of the H2SO4, which would simplify purification since vacuum distillation wouldn't be necessary (HCl/water boil at a lower temp than chloroacetic acid).

After one has the chloroacetic acid in relatively pure form, by whatever method, methanol esterification should not be difficult.

Now, as I recall, methyl fluoroacetate is produced by reacting powdered KF with methyl chloroacetate in an autoclave. The KF is easy: react OTC cleaning products containg ammonium bifluoride or hydrofluoric acid with potassium carbonate (from pottery suppliers or charred cream of tartar).

The autoclave is a bit tougher; it's not the sort of thing one can pick up at the corner supermarket. However, I believe that an adequate makeshift autoclave can be made from a well-sealed metal pipe, as in http://www.rhodium.ws/chemistry/tcboe/chapter7.html. One could of course place the improvised autoclave in the heating bath, retreat, and then turn on the heat. An explosion after considerable quantities of fluoroacetate have been formed could be disastrous, but that's the chance you take.

If the vessel survives, it can be opened once cool to liberate the methyl fluoroacetate, which can in turn be reacted with NaOH to yield a convenient solid instead of a volatile liquid.

Sorry for the heavy speculation, but I find this really exciting. A handful of chemicals and some very inexpensive equipment could yield a deadly and uncommon poison, and the synthetic steps don't seem that hard either, if I can determine the optimum parameters for the TCE hydrolysis.

[nbk2000]

ARRGGHH!!!

I just spent the last hour and a half typing up a reply and my piece of shit computer froze up on me when I closed out of acrobat. :mad:

Needless to say, I didn't have it saved. :(

I'll type it up again tommorrow, but I like you thinking. :)

There's also some information I posted on this subject a while ago, that you may or may not know about, so check that out if you haven't already read it.

[nbk2000]

Rather than retype everything I did the first time, I'll just refer you to this thread ( http://www.roguesci.org/theforum/showthread.php?s=&threadid=1564 ) which covers most of the chemistry I was going to refer to anyways.

Firstly, the prolonged heating of the TCE with the acid may be carbonizing the acetate formed, which is why it's black and chunky.

Perhaps passing TCE vapors through sulfuric acid, heated to the required temperature, would achieve the same efffect without "burning" it into carbon?

And you can make nitromethane with the chloroacetic acid too, so that's an added bonus.

Purification of chloroacetic acid can be found in Vogel's, 3rd ed. (FTP).

I wonder if the hydrolysis of perchloroethylene would make anything useful?

On page 118 of "The War Gases" by Sartori (FTP) is a prep for making ethyl chloroacetate. Basically you reflux chloroacetic acid with alcohol and sulphuric acid, then wash with water to seperate the layers, prior to redistilling. Simple enough, eh? :)

I remember reading how the the lads at Sandia used a 16" artillery shell as a pressure vessel. And I also remember someone linking to a surplus ammo dealer that sold empty 20mm (and larger) shells, fairly cheap and complete with nose plugs, that would make quite nice little autoclave vessels. Thick steel, able to withstand very high pressures, and made to be spun at high speeds...;) And how appropriate to make a CW in an artillery shell. :D

$20 for a 20mm shell wouldn't be too much to be able to cook up an once or two of MFA at a time, considering how toxic it is, and easy to make.

Once you've got the MFA, conversion into the crystalline alpha-fluoroacetamide with ammonia would make it suitable for casting into bullets to poison them, as per RTPB.

Patent #2,403,576 describes the preparation of fluoroacetamides using xylene as a solvent, removing the need for an autoclave, and the resulting products are just as toxic as MFA. These salts can be converted into a liquid, if desired, also of equal toxicity.

Being a liquid, highly stable, non-irritating, delay-action, and rather simple to make, as well as being 5x more toxic than phosgene, it'd seem to me that MFA (and other fluoro-toxins) would be quite suitable for "terrorist" use, without having to bother with the irksome task of aquiring large amounts of watched OPA precursors. Oh, and being convulsants, what are people automatically going to think once they see others keeling over and flopping like fish out of water? "OH MY GOD! NERVE GAS!!" :eek: :p

I think it'd be hilarious if the piggies were sitting in their little NBC-proof trailers at some big event, watching people drop like flies,while the mega-buck CW detectors they bought after 9/11 just sit there saying that everythings honky-dory and the airs just fine! They'd be pissing their pants, not knowing what it was, and what it might be doing to them at the very moment. MWAHAHAA!

[simply RED]

There is another way to produce monofluoroacetic acid:
AgF + ClCH2-COOH =(H2O solution)= AgCl(precipitate) + FCH2-COOH
AgBr and AgI are less soluble than AgCl which makes BrCH2-COOH a better choice.
The reaction is done in water solution, heating is applied until white AgCl precipitate stops to appear. AgF is soluble in water, AgCl is not. If AgF is soluble in chloroacetic acid, and AgCl is not, the reaction will go easier without water.
Fluoroethanol (FCH2-CH2-OH) also seems a good poison, it is metabolized in the body to monofluoroacetic acid. If chloroethanol is easily available(at least noone will be suspecious if you wanna buy), it will be a good choice.
Chloroacetaldehyde can also become deadly poison, fluoroacetaldehyde will become monofluoroacetic acid when the body tries to clean it out...
Also they can be converted with somple oxidation:
XCH2-CH2-OH ---ox---}XCH2-COH----ox}XCH2-COOH
X is halogen.
Some aminoacids with fluorine will be metabolized to monofluoroacetic acid(simple aminoacids, but don't remembrer formulas). Their synthesys is not very hard...
The main "food"(i mean following the Crebs cycle) for the body is acetic acid (its sodium salt), everything is metabolized to acetic acid, so every food with well placed F atom will become monofluoroacetic acid at the end...

[simply RED]

So, all you need is ( love :D :D :D ):
AgNO3 , NaOH, ClCH2-COOH, HF, all found at no cost in almost every chem shop.
AgNO3 + NaOH = AgOH precipitate (Ag2O + H2O) + NaNO3
Filter the precipitate. And dissolve it in HF.
Ag2O + 2HF = 2AgF + H2O
Dry in execator or use precipitating process with some organic solvent.
Till this, you have nothing so poisonous. (AgF is merciless if swallowed (AgF + HCl= AgCl + HF!!!)
Next step:
Fill a flask with 50% water solution of ClCH2-COOH and add AgF at low temperature.
Solder the end of the flask with gas burner (the flask must be quarz) or use another good way to seal at 100%.
Gently heat the flask maintaining the temperature and pressure that it will not burst. Heat until no precipitate appears.
Now, you have a flask with fluoroacetic acid.....

[nbk2000]

Anything using silver is going to be incredibly expensive for anything quantities useful for more than just a single homicide. :(

Here's one of the shells I was thinking would be useful as a poor mans autoclave.

http://bigskysurplus.com/images/20mm_oerlikon_projectiles_od_green.jpg

Only fifty cents each in quantities of 100. :) Which is also the minimum order. :(

But, if one was serious about it, then you'd want to get at least a 155mm shell, because of the large internal capacity.

[Mr Cool]

The silver could be re-used, though. I think roasting silver chloride will yield silver.
Those shells are an interesting idea, I might look into getting a couple. Specifically, for phosphorus production. Put your pipe that goes into your warm water bath (for phossy collection) in the top thingy, braze it in place, and put your (HPO3)n and Al in the body. Drop in a plaster incendiary igniter, with a Zn/S pellet to ignite that, and some slow fuse to ignite that, screw it all together, and watch your phossy pour out :D. (HPO3)n/Al is certainly exothermic, although hard to ignite. In a coal fire I could only get it going with a forced feed of hot air (yellow/white hot), but then, it burned quickly. I think plaster incendiary should do it though, I'll have to try. Ah, but this all belongs elsewhere...

[Polverone]

I tried the TCE hydrolysis again, this time at a higher temperature and with slightly less concentrated acid. Still ended up with a bunch of tarry black junk, though. Sadly, I won't be able to experiment in this area for some time since I'm moving all my stuff into storage for the summer, before I start grad school in the fall.

Silver isn't prohibitively expensive. If you buy silver compounds from a chem supplier, they will be, but silver's something like $6/ounce bought in bulk bullion form. That's not cheap, but it's less expensive than a lot of what you'll find in a Sigma-Aldrich catalog, and the metal can be recycled as mentioned previously.

I'd be very excited to hear about progress in the phosphorus manufacture department. I had a bit of a realization a couple months ago. I realized that, yes, aluminum + silica + a metaphosphate will produce elemental phosphorus rapidly and easily. Then I realized that I really didn't want to deal with hot phosphorus vapor. Any work in this area will require a substantial upgrade in the quality of apparatus I buy/assemble.

[nbk2000]

Sure, silvers not too expensive...in small amounts...but when you've got to make multi-kilo sized batches to wipe out a building it gets...expensive/tedious. ;)

Recycling silver is something we do at my current job, at the photolab. Pain in the ass! Especially if you're having to do it an ounce or two at a time, in between batches. Pfhuuuuttt! :p

You still got the black tar, but have you tried seperating the CAA, for an idea of yeild? Even if it was only half, with crap mixed in, as long as it could be seperated, then it'd be worth it, since TCE is cheap.

[Polverone]

After finding some patents on the production of chloroacetic acid from trichloroethylene, I think that Ullmann's may have given misleadingly low values for the % concentration of H2SO4 used to hydrolyze TCE. 90% and up appears to be used. Also, as NBK suggested in one of the first replies in this thread, passing TCE vapor into preheated H2SO4 does appear to be one of the methods appearing in patent documents. Here's the post I made about my more recent findings on That Other Site I run:
US1304108 mentions producing monochloroacetic acid from trichloroethylene by heating it with water and high-conc. H2SO4 to 150-200 degrees. Alternatively, trichloroethylene vapor is passed into hot sulfuric acid (this sounds more palatable for those without pressure vessels).

Also, it says that "It is true that it has been proposed in the patent literature to make ethyl chloroacetate or monochloroacetic acid by treating dichlorovinyl ether with water or alcohol. It is also known that dichlorovinyl ether is derived from trichloroethylene by the action of an alkali or of sodium ethylate in alcoholic solution."

This two-stage reaction might be of interest to a chemist of limited means.

US1322898 (for some reason not on Espacenet, but on uspto.gov) is an even more interesting read in certain aspects. It asserts that up to an H2SO4 concentration of 90% or so, the trichloroethylene merely carries water away from the acid unchanged. This is in sharp contrast to Ullmann's statement that TCE is hydrolyzed with 70% H2SO4, and may explain why I had so little luck producing monochloroacetic acid with somewhat diluted H2SO4.

British patent 132042 is also supposed to be a process for producing monochloroacetic acid from TCE, but Espacenet appears not to have it.

[nbk2000]

Also, as NBK suggested in one of the first replies in this thread, passing TCE vapor into preheated H2SO4 does appear to be one of the methods appearing in patent documents.


What can I say, my genius knows no bounds! :p

I'm downloading those patents now, and will be reading them shortly.

BTW, COPAE was one of my early scans, so please credit it to me on your site. Thanks. If you have SIPRI's "Incendiary Weapons", feel free to up it with credit to me too. ;)