Thiophosgene
| Thiophosgene | |
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Carbonothioyl dichloride |
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Other names
Thiophosgene; Thiocarbonyl chloride; Carbonothioic dichloride |
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| Identifiers | |
| CAS number | 463-71-8  |
| PubChem | 10040 |
| ChemSpider | 9645 |
| UNII | 067FQP576P |
| ChEBI | CHEBI:29366 |
| RTECS number | XN2450000 |
| Jmol-3D images | Image 1 |
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| Properties | |
| Molecular formula | CSCl2 |
| Molar mass | 114.98 g/mol |
| Appearance | Red liquid |
| Density | 1.50 g/cm3 |
| Boiling point |
70–75 °C |
| Solubility in water | Decomposition |
| Solubility in other solvents | polar organic solvents rxn with amines and alcohols |
| Refractive index (nD) | 1.558 |
| Structure | |
| Molecular shape | planar, sp2, C2v |
| Hazards | |
| EU Index | Not listed |
| Main hazards | Highly toxic |
| Flash point | 62 °C |
| Related compounds | |
| Related compounds | Phosgene Sulfur dichloride thionyl chloride |
 (verify) (what is:  / ?)Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
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| Infobox references | |
Thiophosgene is a red liquid with the formula CSCl2. It is a molecule with trigonal planar geometry. There are two reactive C–Cl bonds that allow it to be used in diverse organic syntheses.
Synthesis of CSCl2
CSCl2 is prepared in a two-step process from carbon disulfide. In the first step, carbon disulfide is chlorinated to give trichloromethanesulfenyl chloride, CCl3SCl:
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- CS2 + 3 Cl2 → CCl3SCl + S2Cl2
The chlorination must be controlled as excess chlorine converts trichloromethanesulfenyl chloride into carbon tetrachloride. Steam distillation separates the trichloromethanesulfenyl chloride, a rare sulfenyl chloride, and hydrolyzes the sulfur monochloride. Reduction of trichloromethanesulfenyl chloride produces thiophosgene:
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- CCl3SCl + M → CSCl2 + MCl2
Uses of CSCl2
CSCl2 is mainly used to prepare compounds with the connectivity CSX2 where X = OR, NHR. Such reactions proceed via intermediate such as CSClX. Under certain conditions, one can convert primary amines into isothiocyanates. CSCl2 also serves as a dienophile to give, after reduction 5-thiacyclohexene derivatives. Thiophosgene is also known as the appropriate reagent in Corey-Winter synthesis for stereospecific conversion of 1,2-diols into olefins.[2]
References
- ^ Dyson, G. M. (1926). "Thiophosgene" (pdf). Organic Syntheses 6: 86.
- ^ Sharma, S. (1978). "Thiophosgene in Organic Synthesis". Synthesis 1978 (11): 803–820. doi:10.1055/s-1978-24896.
- Holleman, A. F.; Wiberg, E. (2001), Inorganic Chemistry, San Diego: Academic Press, ISBN 0-12-352651-5
