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| Names | |
|---|---|
| Preferred IUPAC name Trichloromethyl thiohypochlorite | |
Other names
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| Identifiers | |
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3D model (JSmol) | |
| ChEMBL | |
| ChemSpider |
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| ECHA InfoCard | 100.008.948 |
| EC Number |
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| RTECS number |
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| UNII | |
| UN number | 1670 |
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| Properties | |
| Cl3C−S−Cl | |
| Molar mass | 185.87 g·mol−1 |
| Appearance | Oily, colorless liquid |
| Odor | disagreeable, acrid odor |
| Density | 1.72 g/cm3 |
| Melting point | −44 °C (−47 °F; 229 K) |
| Boiling point | 147 to 148 °C (297 to 298 °F; 420 to 421 K) |
| Insoluble, reacts | |
| logP | 3.47 (estimated) |
| Vapor pressure | 0.4 kPa (at 20 °C) |
| Hazards | |
| GHS labelling: | |
   | |
| Danger | |
| H301,H311,H312,H314,H330,H335 | |
| P260,P264,P270,P271,P280,P284,P301+P310,P301+P330+P331,P302+P352,P303+P361+P353,P304+P340,P305+P351+P338,P310,P312,P320,P321,P330,P361,P363,P403+P233,P405,P501 | |
| NFPA 704 (fire diamond) | |
| Lethal dose or concentration (LD, LC): | |
LD50 (median dose) | 82.6 mg/kg (rat, oral)[2] |
LC50 (median concentration) | 11 ppm (rat, 1 hr) 16 ppm (rat, 1 hr) 9 ppm (mouse, 3 hr) 38 ppm (mouse, 2 hr) 11 ppm (rat, 1 hr)[2] |
LCLo (lowest published) | 388 ppm (human, 10 min) 46 ppm (mouse, 10 min)[2] |
| NIOSH (US health exposure limits): | |
PEL (Permissible) | TWA 0.1 ppm (0.8 mg/m3)[1] |
REL (Recommended) | TWA 0.1 ppm (0.8 mg/m3)[1] |
IDLH (Immediate danger) | 10 ppm[1] |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Trichloromethane sulfenyl chloride orperchloromethyl mercaptan is theorganosulfur compound with the formulaCl3C−S−Cl. It is mainly used as an intermediate for the synthesis of dyes and fungicides (captan,folpet). It is a colorless oil, although commercial samples are yellowish. It is insoluble in water but soluble in organic solvents. It has a foul, acrid odor. Perchloromethyl mercaptan is a common name. The systematic name is trichloromethanesulfenyl chloride, because the compound is asulfenyl chloride, not amercaptan.[3]
It was used as achemical warfare agent by the French in the 1915 battle of Champagne. Shortly thereafter, wartime use was abandoned due to the clear warning properties, the decomposition in the presence of iron and steel, and the easy removal of the vapor by charcoal.[4]
The method to prepare perchloromethyl mercaptan was first described by Rathke in 1873[3] and is still used.Carbon disulfide is chlorinated using an iodine catalyst. The following equations operate most efficiently at temperatures below about 30 °C
At higher temperatures, the chlorination givescarbon tetrachloride and additional sulfur chlorides.[5] The formation of byproducts can be suppressed by performing the reaction in the presence ofdiketones.[6] Another byproduct isthiophosgene. The more volatile byproducts such as carbon tetrachloride andsulfur dichloride can be removed bydistillation. The separation of perchloromethyl mercaptan fromS2Cl2 by distillation is challenging since theirboiling points are very close. Another byproduct that forms ishexachloroethane. Innovations in the basic Rathke method have been reported.[6]
The compound slowly hydrolyzes:[6]
Controlled hydrolysis affordschlorocarbonylsulfenyl chloride:[7]
Perchloromethyl mercaptan is corrosive to most metals. It reacts with iron, evolving carbon tetrachloride. Perchloromethyl mercaptan is oxidized by nitric acid totrichloromethanesulfonyl chloride (Cl3C−S(=O)2−Cl), a white solid.[4]
| Animal | Oral | Inhalation | Intraperitoneal | Intravenous | Skin | Eyes |
|---|---|---|---|---|---|---|
| Rat | 82.6 mg/kg | 11 ppm/1h | 25 mg/kg | |||
| Mouse | 40 mg/kg | 296 g/m3/2h | 10 mg/kg | 56 mg/kg | ||
| Rabbit | 1410 mg/kg | |||||
| Guinea Pig | 500 μL/kg | 50 μg/24h[8] |
When it is heated or in a fire, it will emit toxic and corrosive gases. It is also very toxic by inhalation or skin absorption.[3]
At least two mechanisms could account for the toxicity of perchloromethyl mercaptan, as hypothesized by Althoff (1973). The first mechanism is a reaction between perchloromethyl mercaptan and biological functional groups such as hydroxyl, sulfhydryl, amino and carboxyl groups. This results in an inactivation of key enzymes. A second general pathway reaction is the hydrolysis to give hydrochloric acid.[3]
