Thiophosgene

Thiophosgene
IUPAC name Carbonothioyl dichloride
Other names Thiophosgene; Thiocarbonyl chloride; Carbonothioic dichloride
Identifiers
CAS number	463-71-8 Y
PubChem	10040
ChemSpider	9645 Y
UNII	067FQP576P Y
ChEBI	CHEBI:29366 Y
RTECS number	XN2450000
Jmol-3D images	Image 1
SMILES ClC(Cl)=S
InChI InChI=1S/CCl2S/c2-1(3)4 Y Key: ZWZVWGITAAIFPS-UHFFFAOYSA-N Y InChI=1/CCl2S/c2-1(3)4 Key: ZWZVWGITAAIFPS-UHFFFAOYAH
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; 144 °F; 335 K
Related compounds
Related compounds	Phosgene Thiocarbonyl fluoride Thiocarbonyl bromide Sulfur dichloride thionyl chloride
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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:

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.^[1]

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]

Safety considerations

CSCl₂ is considered highly toxic.

References

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