Used as a preplant soil treatment measure, chloropicrin suppresses soilborne pathogenic fungi and some nematodes and insects. 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. EPA protections were increased in both 20, reducing fumigant exposures and significantly improving safety. 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. 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. In the US, occupational exposure limits have been set at 0.1 ppm over an eight-hour time-weighted average. 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. Safety Īt the national level, chloropicrin is regulated by the United States Environmental Protection Agency as a restricted use pesticide. Chloropicrin may stimulate weed germination, which can be useful when quickly followed by a more effective herbicide. Chloropicrin's mode of action is unknown (IRAC MoA 8B). Ĭhloropicrin is used as an indicator and repellent when fumigating residences for insects with sulfuryl fluoride which is an odorless gas. It is commonly used as a stand-alone treatment or in combination / co-formulation with methyl bromide and 1,3-Dichloropropene. Chloropicrin affects a broad spectrum of fungi, microbes, and insects. In agriculture, chloropicrin is injected into soil prior to planting a crop to fumigate soil. Use Ĭhloropicrin was manufactured for use as poison gas in World War I. Its soil adsorption coefficient ( K oc normalized to soil organic matter content) is 25 cm 3/g. The octanol-water partition coefficient ( K ow) of chloropicrin is estimated to be 269. It is volatile, with a vapor pressure of 23.2 millimeters of mercury (mmHg) at 25 ☌ the corresponding Henry's law constant is 0.00251 atmosphere-cubic meter per mole. Chloropicrin is sparingly soluble in water with solubility of 2000 mg/L at 25 ☌. Pure chloropicrin is a colorless liquid, with a boiling point of 112 ☌. Or by the reaction of chloroform with nitric acid:ĬHCl 3 + HNO 3 → CCl 3NO 2 + H 2O Properties Ĭhloropicrin's chemical formula is CCl 3NO 2 and its molecular weight is 164.38 grams/mole. Today, chloropicrin is manufactured by the reaction of nitromethane with sodium hypochlorite: H 3CNO 2 + 3 NaOCl → Cl 3CNO 2 + 3 NaOH HOC 6H 2(NO 2) 3 + 11 NaOCl → 3 Cl 3CNO 2 + 3 Na 2CO 3 + 3 NaOH + 2 NaClīecause of the precursor used, Stenhouse named the compound chloropicrin, although the two compounds are structurally dissimilar. He prepared it by the reaction of sodium hypochlorite with picric acid: Chloropicrin was discovered in 1848 by Scottish chemist John Stenhouse.
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