Tabun (nerve agent)

Last updated
Tabun
GA-3D-balls-by-AHRLS-2011.png
Tabun.svg
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
PubChem CID
UNII
  • InChI=1S/C5H11N2O2P/c1-4-9-10(8,5-6)7(2)3/h4H2,1-3H3 Yes check.svgY
    Key: PJVJTCIRVMBVIA-UHFFFAOYSA-N Yes check.svgY
  • 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
AppearanceColorless 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.svgHealth 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).
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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).

Contents

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 Gerhard Schrader. In the chemical agent factory in Dyhernfurth an der Oder, codenamed "Hochwerk", at least 12,000 metric tons of this agent were manufactured between 1942 and 1945. The manufacturing process consisted of two steps (see below); after the reactions, the mixture (consisting of ~75% solvent, ~25% desired product, plus insoluble salts and reactants) was filtered and vacuum-distilled. This yielded a technical product consisting either of 95% or 80% tabun (then known as Tabun A or B, respectively,[ inconsistent ] the second a product later in the war). [4] [ verification needed ][ better source needed ]

TabunSynthesis.png

Modern synthesis

Effects of exposure

The symptoms of exposure include: [5] [6] [7] nervousness/restlessness, miosis (contraction of the pupil), rhinorrhea (runny nose), excessive salivation, dyspnea (difficulty in breathing due to bronchoconstriction/secretions), 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. [6] A person's clothing can release the toxic chemical for up to 30 minutes after exposure. [2] Inhaled lethal dosages kill in one to ten minutes, and liquid absorbed through the eyes kills almost as quickly. However, people who experience mild to moderate exposure to tabun can recover completely, if treated almost as soon as exposure occurs. [2] The median lethal dose (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 atropine. [7] 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

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 World War II, as part of the Grün 3 program, a plant for the manufacture of tabun was established at Dyhernfurth (now Brzeg Dolny, Poland), in 1939. [14] Run by Anorgana GmbH, the plant began production of the substance in 1942. [14] The reason for the delay was the extreme precautions used by the plant. [14] Intermediate products of tabun were corrosive, and had to be contained in quartz or silver-lined vessels. Tabun itself was also highly toxic, and final reactions were conducted behind double glass walls. [14] Large scale manufacturing of the agent resulted in problems with tabun's degradation over time, and only around 12,500 tons of material were manufactured before the plant was seized by the Soviet Army.[ citation needed ] The plant initially produced shells and aerial bombs using a 95:5 mix of tabun and chlorobenzene, designated "Variant A".[ inconsistent ] In the latter half of the war, the plant switched to "Variant B",[ inconsistent ] an 80:20 mix of tabun and chlorobenzene designed for easier dispersion. [4] [ verification needed ][ 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 Iran–Iraq War of 1980 to 1988, Iraq employed quantities of chemical weapons against Iranian ground forces. Although the most commonly used agents were mustard gas and sarin, tabun and cyclosarin were also used. [7] [17] [ 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

Related Research Articles

Nerve agents, sometimes also called nerve gases, are a class of organic chemicals that disrupt the mechanisms by which nerves transfer messages to organs. The disruption is caused by the blocking of acetylcholinesterase (AChE), an enzyme that catalyzes the breakdown of acetylcholine, a neurotransmitter. Nerve agents are irreversible acetylcholinesterase inhibitors used as poison.

<span class="mw-page-title-main">Chemical warfare</span> Using poison gas or other toxins in war

Chemical warfare (CW) involves using the toxic properties of chemical substances as weapons. This type of warfare is distinct from nuclear warfare, biological warfare and radiological warfare, which together make up CBRN, the military acronym for chemical, biological, radiological, and nuclear, all of which are considered "weapons of mass destruction" (WMDs), a term that contrasts with conventional weapons.

<span class="mw-page-title-main">Sarin</span> Chemical compound and chemical warfare nerve agent

Sarin is an extremely toxic organophosphorus compound. A colourless, odourless liquid, it is used as a chemical weapon due to its extreme potency as a nerve agent. Exposure can be lethal even at very low concentrations, where death can occur within one to ten minutes after direct inhalation of a lethal dose, due to suffocation from respiratory paralysis, unless antidotes are quickly administered. People who absorb a non-lethal dose and do not receive immediate medical treatment may suffer permanent neurological damage.

<span class="mw-page-title-main">Soman</span> Chemical compound (nerve agent)

Soman is an extremely toxic chemical substance. It is a nerve agent, interfering with normal functioning of the mammalian nervous system by inhibiting the enzyme cholinesterase. It is an inhibitor of both acetylcholinesterase and butyrylcholinesterase. As a chemical weapon, it is classified as a weapon of mass destruction by the United Nations according to UN Resolution 687. Its production is strictly controlled, and stockpiling is outlawed by the Chemical Weapons Convention of 1993 where it is classified as a Schedule 1 substance. Soman was the third of the so-called G-series nerve agents to be discovered along with GA (tabun), GB (sarin), and GF (cyclosarin).

<span class="mw-page-title-main">VX (nerve agent)</span> Chemical compound and chemical warfare nerve agent

VX is an extremely toxic synthetic chemical compound in the organophosphorus class, specifically, a thiophosphonate. In the class of nerve agents, it was developed for military use in chemical warfare after translation of earlier discoveries of organophosphate toxicity in pesticide research. In its pure form, VX is an oily, relatively non-volatile liquid that is amber-like in colour. Because of its low volatility, VX persists in environments where it is dispersed.

Binary chemical weapons or munitions are chemical weapons which contain the toxic agent in its active state as chemical precursors that are significantly less toxic than the agent. This improves the safety of storing, transporting, and disposing of the weapon. Commonly, firing the munition removes a barrier between two precursors. These react to form the intended agent which is then aerosolized and distributed by a bursting charge.

<span class="mw-page-title-main">Chlorosarin</span> Chemical compound

Chlorosarin is a chemical precursor used in the final step of one method for the production of the nerve agent sarin. Also known as O-isopropyl methylphosphonochloridate and isopropyl methylphosphonic chloride, it has a molecular weight of 156.55 g/mol and a molecular formula of C4H10ClO2P.

Cyclosarin or GF is an extremely toxic substance used as a chemical weapon. It is a member of the G-series family of nerve agents, a group of chemical weapons discovered and synthesized by a German team led by Dr. Gerhard Schrader. The major nerve gases are the G agents, sarin (GB), soman (GD), tabun (GA), and the V agents such as VX. The original agent, tabun, was discovered in Germany in 1936 in the process of work on organophosphorus insecticides. Next came sarin, soman and finally, cyclosarin, a product of commercial insecticide laboratories prior to World War II.

<span class="mw-page-title-main">VG (nerve agent)</span> Chemical compound

VG is a "V-series" nerve agent chemically similar to the better-known VX nerve agent. Tetram is the common Russian name for the substance. Amiton was the trade name for the substance when it was marketed as an insecticide by ICI in the mid-1950s.

Gerhard Schrader was a German chemist specializing in the discovery of new insecticides, hoping to make progress in the fight against hunger in the world. Schrader is best known for his accidental discovery of nerve agents including sarin and tabun. Sarin is partially named after him: It was named in honor of its discoverers, Schrader, Otto Ambros, Gerhard Ritter, and Hans-Jürgen von der Linde.

Novichok is a family of nerve agents, some of which are binary chemical weapons. The agents were developed at the GosNIIOKhT state chemical research institute by the Soviet Union and Russia between 1971 and 1993. Some Novichok agents are solids at standard temperature and pressure, while others are liquids. Dispersal of solid form agents is thought possible if in ultrafine powder state.

Chemical, biological (CB) — and sometimes radiological — warfare agents were assigned what is termed a military symbol by the U.S. military until the American chemical and biological weapons programs were terminated. Military symbols applied to the CB agent fill, and not to the entire weapon. A chemical or biological weapon designation would be, for example, "Aero-14/B", which could be filled with GB, VX, TGB, or with a biological modification kit – OU, NU, UL, etc. A CB weapon is an integrated device of (1) agent, (2) dissemination means, and (3) delivery system.

<span class="mw-page-title-main">Mark I NAAK</span>

In the United States military, the Mark I NAAK, or MARK I Kit, is a dual-chamber autoinjector: Two anti-nerve agent drugs—atropine sulfate and pralidoxime chloride—each in injectable form, constitute the kit. The kits are only effective against the nerve agents tabun (GA), sarin (GB), soman (GD) and VX.

Methylphosphonyl difluoride (DF), also known as EA-1251 or difluoro, is a chemical weapon precursor. Its chemical formula is CH3POF2. It is a Schedule 1 substance under the Chemical Weapons Convention. It is used for production of sarin and soman as a component of binary chemical weapons; an example is the M687 artillery shell, where it is used together with a mixture of isopropyl alcohol and isopropyl amine, producing sarin.

<span class="mw-page-title-main">VR (nerve agent)</span> Chemical compound

VR is a "V-series" unitary nerve agent closely related to the better-known VX nerve agent. It became a prototype for the series of Novichok agents. According to chemical weapons expert Jonathan Tucker, the first binary formulation developed under the Soviet Foliant program was used to make Substance 33, differing from VX only in the alkyl substituents on its nitrogen and oxygen atoms. "This weapon was given the code name Novichok."

Throughout history, chemical weapons have been used as strategic weaponry to devastate the enemy in times of war. After the mass destruction created by WWI and WWII, chemical weapons have been considered to be inhumane by most nations, and governments and organizations have undertaken to locate and destroy existing chemical weapons. However, not all nations have been willing to cooperate with disclosing or demilitarizing their inventory of chemical weapons. Since the start of the worldwide efforts to destroy all existing chemical weapons, some nations and terrorist organizations have used and threatened the use of chemical weapons to leverage their position. Examples of the use of chemical weapons since World War II are Iraq’s Saddam Hussein on the Kurdish village Halabja in 1988 and their employment against civilian passengers of the Tokyo subway by Aum Shinrikyo in 1995. The efforts made by the United States and other chemical weapon destruction agencies intend to prevent such use, but this is a difficult and ongoing effort. Aside from the difficulties of cooperation and locating chemical weapons, the methods to destroy the weapons and to do this safely are also a challenge.

<span class="mw-page-title-main">Dimethylamidophosphoric dichloride</span> Chemical compound

Dimethylamidophosphoric dichloride is a chemical used in industrial applications. It is used for synthesizing phosphoramidates as well as Nerve agent GA which is used as a chemical weapon.

The United States chemical weapons program began in 1917 during World War I with the creation of the U.S. Army's Gas Service Section and ended 73 years later in 1990 with the country's practical adoption of the Chemical Weapons Convention. Destruction of stockpiled chemical weapons began in 1986 and was completed on July 7, 2023. The U.S. Army Medical Research Institute of Chemical Defense (USAMRICD), at Aberdeen Proving Ground, Maryland, continues to operate.

References

  1. ↑ PubChem. "Tabun". pubchem.ncbi.nlm.nih.gov. Retrieved 2022-07-03.
  2. 1 2 3 4 5 6 Facts About Tabun, National Terror Alert Response System
  3. ↑ "Sodium Hypochlorite - Medical Countermeasures Database - CHEMM". chemm.hhs.gov. Retrieved 2023-11-25.
  4. 1 2 Lohs, K. (1967). "3. Gifte, deren Wirkung sich hauptsächlich auf das Nervensystem bzw. [beziehungsweise] auf lebenswichtige Enzyme erstreckt [Poisons, mainly affecting the nervous system, in particular involving vital enzymes]". Synthetische Gifte: Zur Chemie, Toxikologie und zu Problemen ihrer völkerrechtswidrigen Anwendung durch imperialistische Armeen [Synthetic poisons: On the chemistry, toxicology and problems of their illegal use by imperialist armies](PDF) (in German) (überarb. u. erg. [rev. and expand.] ed.). Berlin [East]: Militärverlag der Deutschen Demokratischen Republik (Military Publisher's of the German Democratic Republic). Retrieved 31 March 2024.[ better source needed ] The translations of chapter and book title here were editor-generated.
  5. 1 2 "Nerve Agent: GA". Cbwinfo.com. Archived from the original on 2011-09-27. Retrieved 2008-11-06.
  6. 1 2 "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. 1 2 3 "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. ↑ Petroianu, Georg (2014). "Pharmacists Adolf Schall and Ernst Ratzlaff and the synthesis of tabun-like compounds: a brief history". Die Pharmazie. 69 (October 2014): 780–784. doi:10.1691/ph.2014.4028. 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. 1 2 3 4 5 6 "A Short History of the Development of Nerve Gases". Noblis.org. Archived from the original on 2011-04-15. Retrieved 2008-11-06.
  15. 1 2 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

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