Trashcanman
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Tetraethyl pyrophosphate(TEPP) as a nerve agent?
It is a cholinesterase inhibitor and according to the attached datasheet the lethal dose of TEPP(when absorbed through the skin) is between
350 to 600mg.
It has a low vapour pressure which is close to the value of VX.
Below 0 degrees celsius it is solid which would probably be a disadvantage when used as a chemical weapon.
Its toxicity appears to be in the same ballpark as Tabun and DFP.
I couldn't find any information on it ever being weaponized(not even by the Iraqis).
Is there a reason why it wasn't produced for that purpose and why I couldn't find any mention of it having a potential use as a nerve agent.
Attachment: TeppDatasheet.pdf (172kB)
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Attachment: TabunDatasheet.pdf (98kB)
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Attachment: DfpDatasheet.pdf (136kB)
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Attachment: Pesticide TEPP Lethal Dose 1958 CDC.mp4 (1.7MB)
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bnull
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Quote: Originally posted by Trashcanman  | | Is there a reason why it wasn't produced for that purpose and why I couldn't find any mention of it having a potential use as a nerve agent.
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It is miscible with water and easy to hydrolyse, which renders it quite useless in a battlefield (except to kill insects in a trench). All one would
need is basically a hot bath and some atropine.
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Trashcanman
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I think the aspect of TEPP being miscible with water is a good point but the hydrolysis half life at 25 degrees celsius is 6.8
hours(page 286 in the attached file).
This makes it useless if the intention is to contaminate an area for a long period of time but on the other hand the limited persistence seems to be
useful if area denial is not the ultimate goal.
Furthermore I doubt that hot baths are something that is normally available on a battlefield 
48 hours after deployment almost the entire TEPP would be gone.
f(x)=100∗(12)486.8=0.75%
Attachment: UllmannsInsectControl.pdf (1.2MB)
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Dr.Bob
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That is scary given I have used some similar tetraalkylpyrophosphates on large scale, and never saw anything on them about being toxic. I'll have to
check their MSDSs better next time. I don't particularly like phosphorous chemistry, so I seem to have to do a lot of it...
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bnull
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Ah, sheesh... double post. I knew the adapter cable was a little bugged. Never mind that.
I remember reading in an old encyclopedia (1962 Larousse, the volume on agriculture) that those who have been poisoned by organophosphorus
insecticides should never use them again. Increased sensitivity or something along that line.
I wonder why I wrote hot bath (I wanted one, I guess). What I meant is that TEPP can be washed from the body. One could even go the British way and
use urine to wash that thing off.
Hydrolysis half-life is 6.8 hours in distilled water. It will be quite smaller when pH is far from 7. The article by R. Mühlmann and G. Schrader,
Hydrolyse der Insektiziden Phosphosäureester (here, in German), has a table (p.11) with the hydrolysis constants at 70°C for several organophosphorus insecticides. The constants increase
considerably at pH 9. A little bag of bicarbonate wouldn't be to difficult to carry.
[Edited on 5-1-2025 by bnull]
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Trashcanman
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| Quote: Originally posted by bnull | Ah, sheesh... double post. I knew the adapter cable was a little bugged. Never mind that.
I remember reading in an old encyclopedia (1962 Larousse, the volume on agriculture) that those who have been poisoned by organophosphorus
insecticides should never use them again. Increased sensitivity or something along that line.
I wonder why I wrote hot bath (I wanted one, I guess). What I meant is that TEPP can be washed from the body. One could even go the British way and
use urine to wash that thing off.
Hydrolysis half-life is 6.8 hours in distilled water. It will be quite smaller when pH is far from 7. The article by R. Mühlmann and G. Schrader,
Hydrolyse der Insektiziden Phosphosäureester (here, in German), has a table (p.11) with the hydrolysis constants at 70°C for several organophosphorus insecticides. The constants increase
considerably at pH 9. A little bag of bicarbonate wouldn't be to difficult to carry.
[Edited on 5-1-2025 by bnull] |
I don't know anything about organophosphorus insecticide exposure leading to an increased sensitivity but I heard about long term effects(brain
damage) after exposure to nerve agents.
Thanks for referencing the article with the hydrolysis table.
Now it makes sense why nobody(military) has tried to weaponize TEPP(at least officially)...Compounds like Tabun(GA), Cyclosarin(GF) and VX fit the
same niche(low volatility) while having all the effects of TEPP that would make it seem desirable as a chemical weapon and none of its
downsides.
I think from now on I will call TEPP "the poor man's Tabun" 
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