Thiophosgene

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Thiophosgene
Thiophosgene
Thiophosgene
IUPAC name Thiophosgene
Other names Thiocarbonylchloride
Identifiers
CAS number [463-71-8]
RTECS number XN2450000
Properties
Molecular 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
Main hazards highly toxic
R-phrases 22-23-36/37/38
S-phrases 7-9-36/37-45
Related compounds
Related compounds COCl2
SCl2

SOCl2
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)
Infobox disclaimer and 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.

Contents

[edit] 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.

[edit] 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.

[edit] Safety considerations

CSCl2 is considered highly toxic.

[edit] References

 The references in this article would be clearer with a different or consistent style of citation, footnoting, or external linking.
  • Dyson, G. M. "Thiophosgene" Organic Syntheses, Coll. Vol. 1, p.506; Vol. 6, p.86.
  • Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.
  • Sharma, S. "Thiophosgene in Organic Synthesis" Synthesis, 1978, pages 804-820.
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