Soman
| Structural formula | ||||||||||
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| Mixture of four stereoisomers (simplified structural formula without stereochemistry) | ||||||||||
| General | ||||||||||
| Surname | Soman | |||||||||
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| Molecular formula | C 7 H 16 FO 2 P | |||||||||
| Brief description |
colorless to yellow-brown liquid |
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| properties | ||||||||||
| Molar mass | 182.18 g mol −1 | |||||||||
| Physical state |
liquid |
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| density |
1.02 g cm −3 |
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| Melting point |
−42 ° C |
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| boiling point |
167 ° C |
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| Vapor pressure |
53 Pa (25 ° C) |
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| solubility |
little in water (21 g l −1 at 20 ° C) |
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| Toxicological data | ||||||||||
| As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . | ||||||||||
Soman is a chemical warfare agent usable neurotoxin . Of the three nerve agents developed in Germany, soman, sarin and tabun , soman is the most toxic and persistent compound. The abbreviation for Soman used in NATO is "GD".
Soman is the 1,2,2-trimethylpropyl ester of methylfluorophosphonic acid and is related to sarin . It differs from sarin in that a methyl group (–CH 3 ) in the sarin has been replaced by a tert - butyl group (–C (CH 3 ) 3 ). Soman, which is liquid under standard conditions and smells like camphor, is sparingly soluble in water and stable to sunlight; it hydrolyzes slowly in air.
history
Soman was synthesized in the spring of 1944 by the Nobel Prize-winning Austro-German chemist Richard Kuhn and his colleague Konrad Henkel . Until the end of the Second World War, only small quantities were produced for test purposes, which were subsequently brought to the Soviet Union .
Soman was produced in large quantities in the Soviet Union during the Cold War . The warfare agent had the code designation "R-55" in the Soviet armed forces. Like many other warfare agents, Soman was also stored or ammunitioned after mixing with an organic polymer as a thickened warfare agent; In this way, the high toxicity should be combined with a long period of sedentarism. At room temperature, this thickened soman, called "VR-55" in the Soviet Union, has a honey- like consistency. VR-55 has a far greater persistence as well as an increased toxicity through the skin than unthickened soman. In the literature, the term “GV” (“V” for viscous , “tough, viscous”) is wrongly found - however, the actual nerve agent GV is based on a different active ingredient.
Protective measures
Nerve agents are deadly even in the smallest quantities. The target is the entire body. Therefore, only a full-body protective suit and a protective mask with a respiratory filter offer sufficient protection. Before using warfare agents, oxime tablets or carbamates such as pyridostigmine or physostigmine can be taken. Obidoxime chloride only works within a few minutes after the appearance of the first symptoms of intoxication, as the enzyme complex ages very quickly with Soman compared to other warfare agents . Delayed administration of obidoxime can even worsen the symptoms. Monotherapy with atropine is then preferable.
Oxidizing agents (e.g. chlorinated lime or calcium hypochlorite ), alkaline solutions and non-aqueous media, e.g. amino alcoholates , can be used for decontamination , as nerve agents are sensitive to oxidizing agents and their hydrolysis is accelerated in an alkaline environment. Sodium carbonate solution, for example, can be used on sensitive surfaces, which naturally works more slowly.
In an experiment with rats, a ketogenic diet resulted in reduced mortality . After cumulative administration of 627 µg / kg soman, 90% of the rats on a ketogenic diet survived compared to 55% of the rats on a standard diet. The former also had fewer performance deficits and showed fewer examples of improper behavior in contrast to groups of rats given other forms of diet.
Symptoms
- Slight poisoning: headache, shortness of breath, heavy sweating, severe visual disturbances combined with eye pain, increased production of nasal secretions, tears and saliva.
- Moderate poisoning: severe headache, nausea, vomiting, diarrhea, eye pain, convulsions with impaired consciousness.
- Severe poisoning: spasms of the skeletal muscles up to convulsions, vomiting, severe shortness of breath, anxiety, confusion.
Death occurs through respiratory paralysis .
Structural formula, stereoisomers
Soman contains two stereocenters, one on the phosphorus atom and one on the first carbon atom of the trimethylpropyl ester . Hence there are four stereo isomers . Soman is a mixture of four different isomers with different physiological effects. In the literature, the isomers are usually referred to as follows: C (+) P (+) - soman, C (-) P (-) - soman, C (+) P (-) - soman and C (-) P ( +) - Soman, where C (-) corresponds to the S configuration on the chiral carbon atom and P (-) corresponds to the S configuration on the phosphorus atom.
The C (±) P (±) -soman produced from racemic pinacolyl alcohol is an isomer mixture which consists of the two isomer pairs
[ C (+) P (+) - soman / C (-) P (-) - soman ] and [ C (+) P (-) - Soman / C (-) P (+) - Soman ] in a ratio of 45:55 (each with the same amount of enantiomers). The individual stereoisomers differ greatly in their toxicity. The table shows toxicological data for the individual soman isomers and for other nerve gases for comparison.
Toxicity of soman isomers and other nerve gases:
| Substance or isomer | LD 50 (mouse, µg / kg) |
|---|---|
| C (±) P (±) -Soman [P RS C RS -Soman] | 156 (sc) |
| C (-) P (-) - Soman [P S C S -Soman] | 38 (sc) |
| C (+) P (-) - Soman [P S C R -Soman] | 99 (sc) |
| C (-) P (+) - Soman [P R C S -Soman] | > 2000 (sc) |
| C (+) P (+) - Soman [P R C R -Soman] | > 5000 (sc) |
| (±) -Sarin [( RS ) -Sarin] | 83 (iv) |
| (-) - Sarin [( S ) -Sarin] | 41 (iv) |
| (+) - Sarin [( R ) -Sarin] | not available |
| (±) -Tabun [( RS ) -Tabun] | 208 (iv) |
| (-) - Tabun [( S ) -Tabun] | 119 (iv) |
| (+) - Tabun [( R ) -Tabun] | 837 (iv) |
| (±) -VX [( RS ) -VX] | 20.1 (iv) |
| (-) - VX [( S ) -VX] | 12.6 (iv) |
| (+) - VX [( R ) -VX] | 165 (iv) |
Analytics
Soman can be reliably identified through adequate sample preparation and subsequent gas chromatography in combination with mass spectrometry . Both urine and blood samples can be used to reliably detect exposure to soman. As a rule, the metabolites such as B. the alkyl methylphosphonic acids isolated with suitable sample preparation and optionally derivatized for GC-MS analysis. According to recent publications, the examination of fingernails or toenails and hair is particularly suitable for long-term evidence of exposure to soman .
International controls
As a chemical on “List 1” in the international CWC disarmament treaty, Soman is controlled by the responsible UN agency, the Organization for the Prohibition of Chemical Weapons (OPCW) based in The Hague . Manufacture or possession is prohibited; This does not apply to work that only serves to protect against these substances or for research. In Germany, any non-governmental handling of soman must be approved by the Federal Office of Economics and Export Control (BAFA) and reported to the OPCW.
Individual evidence
- ↑ Entry on Soman. In: Römpp Online . Georg Thieme Verlag, accessed on June 1, 2014.
- ↑ a b c d e Entry on Soman in the GESTIS substance database of the IFA , accessed on December 27, 2019(JavaScript required) .
- ^ A b c Charles Edward Stewart: Weapons of mass casualties and terrorism response handbook. Jones & Bartlett Learning, 2006, ISBN 0-7637-2425-4 , p. 23.
- ^ A b Günter Hommel: Handbook of dangerous goods. Volume 6 Springer Berlin Heidelberg, 2012, ISBN 978-3-642-25051-4 , p. 2283.
- ↑ Florian Schmaltz: Warfare agent research in National Socialism: On the cooperation of Kaiser Wilhelm Institutes, the military and industry . Wallstein Verlag, 2005, ISBN 3-89244-880-9 , p. 490 ( limited preview in Google Book search).
- ↑ Saskia Eckert: Development of a dynamic model for studying the protective effects of reversible acetylcholinesterase inhibitors against irreversible inhibition by highly toxic organophosphates (PDF; 1.24 MB) , dissertation at the University of Munich, 2006, p. 1.
- ↑ L. Szinicz and SI Baskin: Chemical and biological warfare agents. In: Textbook of Toxicology. 2nd edition, WV mbH, Stuttgart 2004, ISBN 978-3-8047-1777-0 , pp. 865-895.
- ↑ JL Langston, TM Myers: Diet composition modifies the toxicity of repeated soman exposure in rats. Neurotoxicology , 2011, 32: 907-915, PMID 21641933 .
- ^ HP Benschop, LPA De Jong: Nerve agent stereoisomers: analysis, isolation and toxicology. In: Acc. Chem. Res. Volume 21 , no. 10 , 1988, pp. 368-374 , doi : 10.1021 / ar00154a003 .
- ↑ AK Singh, RJ Zeleznikar Jr, LR Drewes: Analysis of soman and sarin in blood utilizing a sensitive gas chromatography-mass spectrometry method. In: J. Chromatogr. 324 (1), 1985, 163-172, PMID 2989304 .
- ^ DD Richardson, JA Caruso: Derivatization of organophosphorus nerve agent degradation products for gas chromatography with ICPMS and TOF-MS detection. In: Anal. Bioanal. Chem. 388 (4): 2007, 809-823, PMID 17356819 .
- ↑ AS Appel, BA Logue: Analysis of nerve agent metabolites from nail clippings by liquid chromatography tandem mass spectrometry. In: J. Chromatogr. B. Analyt Technol Biomed Life Sci. 1031: 2016, 116-22, PMID 27474780 .
- ^ AS Appel, JH McDonough, JD McMonagle, BA Logue: Analysis of Nerve Agent Metabolites from Hair for Long-Term Verification of Nerve Agent Exposure. In: Anal. Chem. 88 (12): 2016, 6523-30, PMID 27161086 .
- ↑ Federal Office of Economics and Export Control (BAFA): List 1 chemicals , accessed on February 5, 2018.
- ↑ Federal Office of Economics and Export Control (BAFA): Chemical Weapons Convention , accessed on February 5, 2018.