Tabun (nerve agent)

Source: Wikipedia, the free encyclopedia.
Tabun
Names
IUPAC name
(RS)-Ethyl N,N-Dimethylphosphoramidocyanidate
Other names
GA; Ethyl dimethylphosphoramidocyanidate; Dimethylaminoethoxy-cyanophosphine oxide; Dimethylamidoethoxyphosphoryl cyanide; Ethyl dimethylaminocyanophosphonate; Ethyl ester of dimethylphosphoroamidocyanidic acid; Ethyl phosphorodimethylamidocyanidate; Cyanodimethylaminoethoxyphosphine oxide; Dimethylaminoethodycyanophosphine oxide; EA-1205; TL-1578
Identifiers
3D model (
JSmol
)
ChEMBL
ChemSpider
UNII
  • InChI=1S/C5H11N2O2P/c1-4-9-10(8,5-6)7(2)3/h4H2,1-3H3 checkY
    Key: PJVJTCIRVMBVIA-UHFFFAOYSA-N checkY
  • InChI=1/C5H11N2O2P/c1-4-9-10(8,5-6)7(2)3/h4H2,1-3H3
    Key: PJVJTCIRVMBVIA-UHFFFAOYAG
  • N#CP(=O)(OCC)N(C)C
Properties
C5H11N2O2P
Molar mass 162.129 g·mol−1
Appearance Colorless to brown liquid
Density 1.0887 g/cm3 at 25 °C
1.102 g/cm3 at 20 °C
Melting point −50 °C (−58 °F; 223 K)
Boiling point 247.5 °C (477.5 °F; 520.6 K)
9.8 g/100 g at 25 °C
7.2 g/100 g at 20 °C
Vapor pressure 0.07 mmHg (9 Pa)
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
 Highly toxic. Fires involving this chemical may result in the formation of hydrogen cyanide
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 4: Very short exposure could cause death or major residual injury. E.g. VX gasFlammability 2: Must be moderately heated or exposed to relatively high ambient temperature before ignition can occur. Flash point between 38 and 93 °C (100 and 200 °F). E.g. diesel fuelInstability 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g. calciumSpecial hazards (white): no code
4
2
1
Flash point 78 °C (172 °F; 351 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)

Tabun or GA is an extremely toxic synthetic

organophosphorus compound.[1] It is a clear, colorless, and tasteless liquid with a faint fruity odor.[2] It is classified as a nerve agent because it can fatally interfere with normal functioning of the mammalian nervous system. Its production is strictly controlled and stockpiling outlawed by the Chemical Weapons Convention of 1993. Tabun is the first of the G-series nerve agents along with GB (sarin), GD (soman) and GF (cyclosarin
).

Although pure tabun is clear, less-pure tabun may be brown. It is a volatile chemical, although less so than either sarin or soman.[2]

Tabun can be deactivated chemically using common oxidizing agents such as sodium hypochlorite.[3]

Synthesis

Historic synthesis

Tabun was made on an industrial scale by Germany during World War II, based on a process developed by

better source needed
]

Modern synthesis

Effects of exposure

The symptoms of exposure include:

sweating, bradycardia (slow heartbeat), loss of consciousness, convulsions, flaccid paralysis, loss of bladder and bowel control, apnea (breathing stopped) and lung blisters. The symptoms of exposure are similar to those created by all nerve agents. Tabun is toxic even in minute doses. The number and severity of symptoms which appear vary according to the amount of the agent absorbed and rate of entry of it into the body. Very small skin dosages sometimes cause local sweating and tremors accompanied with characteristically constricted pupils with few other effects. Tabun is about half as toxic as sarin by inhalation, but in very low concentrations it is more irritating to the eyes than sarin. Tabun also breaks down slowly, which after repeated exposure can lead to build up in the body.[2]

The effects of tabun appear slowly when tabun is absorbed through the skin rather than inhaled. A victim may absorb a lethal dose quickly, although death may be delayed for one to two hours.

LD50) for tabun is about 400 mg-min/m3.[8]

The lethal dose for a man is about .01 mg/kg. The median lethal dose for respiration is 400 mg-minute/m3 for humans. Respiratory lethal doses can kill anytime from 1-10 minutes. When the liquid enters the eye, it also can kill just as quickly. When absorbed via the skin, death may occur in 1-2 minutes, or it can take up to 2 hours. [9]

Treatment for suspected tabun poisoning is often three injections of a nerve agent antidote, such as

Pralidoxime chloride (2-PAM Cl) also works as an antidote; however, it must be administered within minutes to a few hours following exposure to be effective.[10]

History

Further information: Nerve agent § History

Research into ethyl dialkylaminocyanophosphonate began in the late 19th century, In 1898, Adolph Schall, a graduate student at the University of Rostock under professor August Michaelis, synthesised the diethylamino analog of tabun, as part of his PhD thesis Über die Einwirkung von Phosphoroxybromid auf secundäre aliphatische Amine.[11] However, Schall incorrectly identified the structure of the substance as an imidoether, and Michaelis corrected him in a 1903 article in Liebigs Annalen, Über die organischen Verbindungen des Phosphors mit dem Stickstoff. The high toxicity of the substance (as well as the high toxicity of its precursors, diethylamidophosphoric dichloride and dimethylamidophosphoric dichloride) wasn't noticed at the time,[citation needed] most likely due to the low yield of the synthetic reactions used.[speculation?]

Tabun became the first nerve agent known after a property of this chemical was discovered by pure accident in late December 1936[2][5][12][13][14] by German researcher Gerhard Schrader.[14] Schrader was experimenting with a class of compounds called organophosphates, which kill insects by interrupting their nervous systems, to create a more effective insecticide for IG Farben, a German chemical and pharmaceutical industry conglomerate, at Elberfeld.[citation needed] The substance he discovered, as well as being a potent insecticide, was enormously toxic to humans; hence, it was named tabun, a tongue-in-cheek codename[according to whom?] to indicate that the substance was 'taboo' (German: tabu) for its intended purpose.[citation needed]

During

better source needed] The Soviets dismantled the plant and shipped it to Russia.[citation needed
]

During the

Nuremberg Trials, Albert Speer, Minister of Armaments and War Production for the Third Reich, testified that he had planned to kill Adolf Hitler in early 1945 by introducing tabun into the Führerbunker ventilation shaft.[15] He said his efforts were frustrated by the impracticality of tabun and his lack of ready access to a replacement nerve agent,[15] and also by the unexpected construction of a tall chimney that put the air intake out of reach.[verification needed
]

The US once considered repurposing captured German stocks of tabun (GA) prior to production of Sarin (GB).[16] Like the other Allied governments, the Soviets soon abandoned tabun (GA) for Sarin (GB) and Soman (GD).[citation needed] Large quantities of the German-manufactured agent were dumped into the sea to neutralize the substance.[citation needed]

Since GA is much easier to produce than the other G-series weapons[citation needed] and the process is comparatively widely understood, countries that develop a nerve agent capability but lack advanced industrial facilities often start by producing GA.[citation needed]

During the

better source needed
]

Tabun was also used in the 1988

Halabja chemical attack.[18]

Producing or stockpiling tabun was banned by the 1993 Chemical Weapons Convention. The worldwide stockpiles declared under the convention were 2 tonnes, and as of December 2015 these stockpiles had been destroyed.[19]

See also

References

  1. ^ PubChem. "Tabun". pubchem.ncbi.nlm.nih.gov. Retrieved 2022-07-03.
  2. ^ a b c d e f Facts About Tabun, National Terror Alert Response System
  3. ^ "Sodium Hypochlorite - Medical Countermeasures Database - CHEMM". chemm.hhs.gov. Retrieved 2023-11-25.
  4. ^
    better source needed
    ] The translations of chapter and book title here were editor-generated.
  5. ^ a b "Nerve Agent: GA". Cbwinfo.com. Archived from the original on 2011-09-27. Retrieved 2008-11-06.
  6. ^ a b "Chemical Warfare Weapons Fact Sheets — Tabun — GA Nerve Agent". Usmilitary.about.com. Archived from the original on 2016-03-03. Retrieved 2008-11-06.
  7. ^ a b c "Tabun | Encyclopedia.com". www.encyclopedia.com.
  8. ^ "ATSDR — MMG: Nerve Agents: Tabun (GA); Sarin (GB); Soman (GD); and VX". Atsdr.cdc.gov. Archived from the original on April 23, 2003. Retrieved 2008-11-06.
  9. ^ PubChem. "Tabun". pubchem.ncbi.nlm.nih.gov. Retrieved 2023-03-02.
  10. ^ Emergency Response Safety and Health Database. TABUN (GA): Nerve Agent. National Institute for Occupational Safety and Health. Accessed April 30, 2009.
  11. PMID 25985570
    .
  12. ^ Chemical Warfare Weapons Fact Sheets Archived 2016-03-03 at the Wayback Machine, about.com
  13. ^ Chemical Weapons: Nerve Agents, University of Washington
  14. ^ a b c d e f "A Short History of the Development of Nerve Gases". Noblis.org. Archived from the original on 2011-04-15. Retrieved 2008-11-06.
  15. ^ a b Speer 1970, pp. 430–31.
  16. ^ Kirby, Reid (2006). "America's Fifteen-Year Struggle for Modern Chemical Weapons" (PDF). Army Chemical Review (Jan.–Jun): 42–44. Archived from the original (PDF) on 2017-02-11. Retrieved 31 March 2024.
  17. ^ ABC News Staff (April 7, 2003). "Facts About the Nerve Agent Tabun". ABCNews.go.com ABC News. Retrieved 31 March 2024.
  18. ^ "1988: Thousands die in Halabja gas attack". March 16, 1988 – via news.bbc.co.uk.
  19. ^ Organisation for the Prohibition of Chemical Weapons (30 November 2016). "Annex 3". Report of the OPCW on the Implementation of the Convention on the Prohibition of the Development, Production, Stockpiling and Use of Chemical Weapons and on Their Destruction in 2015 (Report). p. 42. Retrieved 8 March 2017.

Bibliography

Further reading
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