Thiophosgene

Thiophosgene

Names
IUPAC name Thiophosgene
Other names Thiocarbonyl chloride Carbonothioic dichloride
Identifiers
CAS Number	463-71-8 N
3D model (JSmol)	Interactive image
ECHA InfoCard	100.006.675
RTECS number	XN2450000
CompTox Dashboard (EPA)	DTXSID2060046
SMILES ClC(=S)Cl
Properties
Chemical formula	CSCl2
Molar mass	114.98 g/mol
Appearance	yellow liquid
Density	1.50 g/cm3
Boiling point	70–75 °C
Solubility in water	decomp.
Solubility in other solvents	polar organic solvents rxn with amines, ROH
Refractive index (nD)	1.548
Structure
Molecular shape	planar, sp2, C2v
Hazards
Occupational safety and health (OHS/OSH):
Main hazards	highly toxic
Related compounds
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 yellow liquid with the formula CSCl₂. This compound has a trigonal planar geometry. It possesses two reactive C–Cl bonds that allow this reagent to be used in diverse procedures related to organic synthesis.

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.

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.

Safety considerations

CSCl₂ is considered highly toxic.

References

• Dyson, G. M. "Thiophosgene" Organic Syntheses, Coll. Vol. 1, p. 506; Vol. 6, p. 86.
• Holleman, Arnold Frederik; Wiberg, Egon (2001), Wiberg, Nils (ed.), Inorganic Chemistry, translated by Eagleson, Mary; Brewer, William, San Diego/Berlin: Academic Press/De Gruyter, ISBN 0-12-352651-5
• Sharma, S. "Thiophosgene in Organic Synthesis" Synthesis, 1978, pages 804-820.