Thiophosgene

Thiophosgene

Names
IUPAC name Carbonothioyl dichloride
Other names Thiophosgene; Thiocarbonyl chloride; Carbonothioic dichloride
Identifiers
CAS Number	463-71-8 Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:29366 Y
ChemSpider	9645 Y
ECHA InfoCard	100.006.675
PubChem CID	10040
RTECS number	XN2450000
UNII	067FQP576P Y
InChI InChI=1S/CCl2S/c2-1(3)4 Y Key: ZWZVWGITAAIFPS-UHFFFAOYSA-N Y InChI=1/CCl2S/c2-1(3)4 Key: ZWZVWGITAAIFPS-UHFFFAOYAH
SMILES ClC(Cl)=S
Properties
Chemical formula	CSCl2
Molar mass	114.98 g/mol
Appearance	Red liquid
Density	1.50 g/cm3
Boiling point	70 to 75 °C (158 to 167 °F; 343 to 348 K)
Solubility in water	Decomposition
Solubility in other solvents	polar organic solvents rxn with amines and alcohols
Magnetic susceptibility (χ)	-50.6·10−6 cm3/mol
Refractive index (nD)	1.558
Structure
Molecular shape	planar, sp2, C2v
Hazards
Main hazards	Highly toxic
Flash point	62 °C (144 °F; 335 K)
Related compounds
Related compounds	Phosgene Thiocarbonyl fluoride Thiocarbonyl bromide Sulfur dichloride thionyl chloride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y verify (what is YN ?)
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.^[1]

Preparation 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 (perchloromethyl mercaptan), CCl₃SCl:

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:

CCl₃SCl + M → CSCl₂ + MCl₂

Typically, tin is used for the reducing agent M.^[2]

Uses of CSCl₂

CSCl₂ is mainly used to prepare compounds with the connectivity CSX₂ where X = OR, NHR.^[3] 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.^[4]

Safety considerations

CSCl₂ is considered highly toxic.

References

Further reading

• Holleman, A. F.; Wiberg, E. (2001), Inorganic Chemistry, San Diego: Academic Press, ISBN 0-12-352651-5