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Chloropicrin

Names
IUPAC name Trichloro(nitro)methane
Other names Nitrochloroform Nitrotrichloromethane PS Tri-clor Trichloronitromethane
Identifiers
CAS Number	76-06-2
3D model (JSmol)	Interactive image
Beilstein Reference	1756135
ChEBI	CHEBI:39285
ChEMBL	ChEMBL1327143
ChemSpider	13861343
ECHA InfoCard	100.000.847
EC Number	200-930-9
Gmelin Reference	240197
IUPHAR/BPS	6292
KEGG	C18445
PubChem CID	6423
RTECS number	PB6300000
UNII	I4JTX7Z7U2
UN number	1580
CompTox Dashboard (EPA)	DTXSID0020315
InChI InChI=1S/CCl3NO2/c2-1(3,4)5(6)7Key: LFHISGNCFUNFFM-UHFFFAOYSA-N InChI=1/CCl3NO2/c2-1(3,4)5(6)7Key: LFHISGNCFUNFFM-UHFFFAOYAJ
SMILES ClC(Cl)(Cl)()=O
Properties
Chemical formula	CCl3NO2
Molar mass	164.375 g/mol
Appearance	colorless liquid
Odor	irritating
Density	1.692 g/ml
Melting point	−69 °C (−92 °F; 204 K)
Boiling point	112 °C (234 °F; 385 K) (decomposes)
Solubility in water	0.2%
Vapor pressure	18 mmHg (20°C)
Magnetic susceptibility (χ)	−75.3·10 cm/mol
Hazards
Occupational safety and health (OHS/OSH):
Main hazards	Extremely toxic and irritating to skin, eyes, and lungs. Carcinogenic.
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H301, H314, H330, H370, H372, H410
Precautionary statements	P260, P264, P270, P271, P273, P280, P284, P301+P310, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P307+P311, P310, P314, P320, P321, P330, P363, P391, P403+P233, P405, P501
NFPA 704 (fire diamond)	4 0 3
Lethal dose or concentration (LD, LC):
LC50 (median concentration)	9.7 ppm (mouse, 4 hr) 117 ppm (rat, 20 min) 14.4 ppm (rat, 4 hr)
LCLo (lowest published)	293 ppm (human, 10 min) 340 ppm (mouse, 1 min) 117 ppm (cat, 20 min)
NIOSH (US health exposure limits):
PEL (Permissible)	TWA 0.1 ppm (0.7 mg/m)
REL (Recommended)	TWA 0.1 ppm (0.7 mg/m)
IDLH (Immediate danger)	2 ppm
Except where otherwise noted, data are given for materials in their standard state (at 25 °C , 100 kPa). Y verify (what is  ?) Infobox references

Chloropicrin, also known as PS (from Port Sunlight) and nitrochloroform, is a chemical compound currently used as a broad-spectrum antimicrobial, fungicide, herbicide, insecticide, and nematicide. It was used as a poison gas in World War I and the Russian military has been accused of using it in the Russo-Ukrainian War. Its chemical structural formula is Cl₃C−NO₂.

Synthesis

Chloropicrin was discovered in 1848 by Scottish chemist John Stenhouse. He prepared it by the reaction of sodium hypochlorite with picric acid:

Because of the precursor used, Stenhouse named the compound chloropicrin, although the two compounds are structurally dissimilar.

Today, chloropicrin is manufactured by the reaction of nitromethane with sodium hypochlorite:

Reaction of chloroform and nitric acid also yields chloropicrin:

Properties

Chloropicrin's chemical formula is CCl₃NO₂ and its molecular weight is 164.38 grams/mole. Pure chloropicrin is a colorless liquid, with a boiling point of 112 °C. Chloropicrin is sparingly soluble in water with solubility of 2 g/L at 25 °C. It is volatile, with a vapor pressure of 23.2 millimeters of mercury (mmHg) at 25 °C; the corresponding Henry's law constant is 0.00251 atmosphere-cubic meter per mole. The octanol-water partition coefficient (K_ow) of chloropicrin is estimated to be 269. Its soil adsorption coefficient (K_oc; normalized to soil organic matter content) is 25 cm/g.

Uses

Poison

Chloropicrin was manufactured for use as poison gas in World War I. In World War I, German forces used concentrated chloropicrin against Allied forces as a tear gas. While not as lethal as other chemical weapons, it induced vomiting and forced Allied soldiers to remove their masks to vomit, exposing them to more toxic gases used as weapons during the war.

Agriculture

In agriculture, chloropicrin is injected into soil prior to planting a crop to fumigate soil. Chloropicrin affects a broad spectrum of fungi, microbes and insects. It is commonly used as a stand-alone treatment or in combination / co-formulation with methyl bromide and 1,3-dichloropropene. Chloropicrin is used as an indicator and repellent when fumigating residences for insects with sulfuryl fluoride which is an odorless gas. Chloropicrin's mode of action is unknown (IRAC MoA 8B). Chloropicrin may stimulate weed germination, which can be useful when quickly followed by a more effective herbicide.

In 2008, the US EPA re-approved chloropicrin as safe for use in agricultural settings, stating that treatments "can provide benefits to both food consumers and growers. For consumers, it means more fresh fruits and vegetables can be cheaply produced domestically year-round because several severe pest problems can be efficiently controlled." To ensure chloropicrin is used safely, the EPA requires a strict set of protections for handlers, workers, and persons living and working in and around farmland during treatments. EPA protections were increased in both 2011 and 2012, reducing fumigant exposures and significantly improving safety. Protections include the training of certified applicators supervising pesticide application, the use of buffer zones, posting before and during pesticide application, fumigant management plans, and compliance assistance and assurance measures.

Used as a preplant soil treatment measure, chloropicrin suppresses soilborne pathogenic fungi and some nematodes and insects. According to chloropicrin manufacturers, with a half-life of hours to days, it is completely digested by soil organisms before the crop is planted, making it safe and efficient. Contrary to popular belief, chloropicrin does not sterilize soil and does not deplete the ozone layer, as the compound is destroyed by sunlight. Additionally, chloropicrin has never been found in groundwater, due to its low solubility.

California

In California, experience with acute effects of chloropicrin when used as a soil fumigant for strawberries and other crops led to the release of regulations in January 2015 creating buffer zones and other precautions to minimize exposure of farm workers, neighbors, and passersby.

Safety

At a national level, chloropicrin is regulated in the United States by the United States Environmental Protection Agency as a restricted use pesticide. Because of its toxicity and carcinogenicity, distribution and use of chloropicrin is available only to licensed professionals and specially certified growers who are trained in its proper and safe use. In the US, occupational exposure limits have been set at 0.1 ppm over an eight-hour time-weighted average.

High concentrations

Chloropicrin is harmful to humans. It can be absorbed systemically through inhalation, ingestion, and the skin. At high concentrations, it is severely irritating to the lungs, eyes, and skin.

Damage to protective gear

Chloropicrin and its derivative phosgene oxime have been known to damage or compromise earlier generations of personal protective equipment. Some of the soldiers attacked mentioned a white smoke emerging from their gas masks.

See also

• Trichloronitrosomethane
• Tetrachlorodinitroethane

References

1. ^ NIOSH Pocket Guide to Chemical Hazards. "#0132". National Institute for Occupational Safety and Health (NIOSH).
2. ^ "Chloropicrin". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
3. Foulkes, C. H. (31 January 2012). "GAS!" – The Story of the Special Brigade. Andrews UK Limited. p. 193.
4. "RED Fact Sheet: Chloropicrin" (PDF). US Environmental Protection Agency. 10 July 2008. p. 2. Retrieved 20 September 2013.
5. Office of the Spokesperson (1 May 2024). "Imposing New Measures on Russia for its Full-Scale War and Use of Chemical Weapons Against Ukraine". U.S. Department of State. Archived from the original on 23 May 2024. Retrieved 23 May 2024.
6. "A top Russian general is killed in a Moscow bombing claimed by Ukraine". Associated Press News. 2024-12-17. Retrieved 2024-12-18.
7. Markofsky, Sheldon B. (2005). "Nitro Compounds, Aliphatic". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH.
8. Jackson, Kirby E. (1934). "Chloropicrin". Chemical Reviews. 14 (2): 251–286. doi:10.1021/cr60048a003.
9. ^ "Executive Summary - Evaluation of Chloropicrin As A Toxic Air Contaminant" (PDF). Department of Pesticide Regulation - California Environmental Protection Agency. February 2010. p. iv. Archived from the original (PDF) on 6 October 2013. Retrieved 20 September 2013.
10. Ayres, Leonard P. (1919). The War with Germany (2nd ed.). Washington, DC: United States Government Printing Office. p. 80.
11. Heller, Charles E. (September 1984). "Chemical Warfare in World War I: The American Experience, 1917–1918" (PDF). Leavenworth Papers (10): 23.
12. ^ "Factsheet: Chloropicrin" (PDF). New South Wales: WorkCover. Archived from the original (PDF) on May 20, 2009.
13. Fries, Amos Alfred; West, Clarence Jay (1921). Chemical warfare. McGraw-Hill. p. 144.
14. Chloropicrin in the Pesticide Properties DataBase (PPDB), University of Hertfordshire, accessed 2021-03-10.
15. "IRAC Mode of Action Classification Scheme Version 9.4". IRAC (Insecticide Resistance Action Committee) (pdf). March 2020.
16. Martin, Frank N. (2003). "Development of Alternative Strategies for Management of Soilborne Pathogens Currently Controlled with Methyl Bromide". Annual Review of Phytopathology. 41 (1). Annual Reviews: 325–350. doi:10.1146/annurev.phyto.41.052002.095514. ISSN 0066-4286. PMID 14527332.
17. "Amended Reregistration Eligibility Decision (RED) for Chloropicrin" (PDF). United States Environmental Protection Agency. May 2009. Retrieved 20 September 2013.
18. ^ "Chloropicrin Mitigation Proposal" (PDF). Department of Pesticide Regulation – California Environmental Protection Agency. 15 May 2013. p. 2. Archived from the original (PDF) on 6 October 2013. Retrieved 20 September 2013.
19. "Chloropicrin – Background". Retrieved 20 September 2013.
20. "Chloropicrin Mitigation Proposal" (PDF). Department of Pesticide Regulation – California Environmental Protection Agency. 15 May 2013. p. 2. Archived from the original (PDF) on 6 October 2013. Retrieved 20 September 2013. The Amended RED incorporated final new safety measures to increase protections for agricultural workers and bystanders. These measures establish a baseline for safe use of the soil fumigants throughout the United States, reducing fumigant exposures and significantly improving safety.
21. "Chloropicrin Soil Fumigation in Potato Production Systems". Plant Management Network. American Phytopathological Society. Retrieved 1 Apr 2019.
22. "Control Measures for Chloropicrin" (PDF). California Department of Pesticide Regulation. January 6, 2015. Archived from the original (PDF) on January 28, 2015. Retrieved January 15, 2015. added controls for chloropicrin when it is used as a soil fumigant. The controls are intended to reduce risk from acute (short-term) exposures that might occur near fields fumigated with products containing chloropicrin.
23. "Chloropicrin Mitigation Proposal" (PDF). Department of Pesticide Regulation – California Environmental Protection Agency. 15 May 2013. p. 2. Archived from the original (PDF) on 6 October 2013. Retrieved 20 September 2013. The new measures appearing on soil fumigant Phase 2 labels include buffer zones and posting, emergency preparedness and response measures, training for certified applicators supervising applications, Fumigant Management Plans, and notice to State Lead Agencies who wish to be informed of applications in their states.
24. ^ "Chloropicrin Mitigation Proposal" (PDF). Department of Pesticide Regulation – California Environmental Protection Agency. 15 May 2013. p. 1. Archived from the original (PDF) on 6 October 2013. Retrieved 20 September 2013.
25. "NIOSH Pocket Guide to Chemical Hazards". Centers for Disease Control and Prevention. Retrieved 7 November 2013.
26. "Chloropicrin (PS): Lung Damaging Agent". Emergency Response Safety and Health Database. National Institute for Occupational Safety and Health. August 22, 2008. Retrieved December 23, 2008.

• World War I chemical weapons
• Fumigants
• Pulmonary agents
• Lachrymatory agents
• Vomiting agents
• Nitro compounds
• Trichloromethyl compounds
• Fungicides
• Herbicides
• Insecticides
• Nematicides