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
CompTox Dashboard (EPA)	DTXSID2060046
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	114.97 g·mol−1
Appearance	Red liquid
Odor	Persistent, choking odor
Density	1.50 g/cm3
Boiling point	70 to 75 °C (158 to 167 °F; 343 to 348 K)
Solubility in water	Decomposes
Solubility in other solvents	Reacts with amines and alcohols, soluble in polar organic solvents
Magnetic susceptibility (χ)	-50.6·10−6 cm3/mol
Refractive index (nD)	1.558
Structure
Molecular shape	planar, sp2, C2v
Hazards
Occupational safety and health (OHS/OSH):
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

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 disulfur dichloride. Reduction of trichloromethanesulfenyl chloride produces thiophosgene:

CCl₃SCl + M → CSCl₂ + MCl₂

Tin^[2] and dihydroanthracene^[3] have been used for the reducing agents.

Reactions

CSCl₂ is mainly used to prepare compounds with the connectivity CSX₂ where X = OR, NHR.^[4] 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 alkenes.^[5]

It forms a head-to-tail dimer upon irradiation with UV light:^[6]

2 CSCl₂ → S₂(CCl₂)₂

Unlike thiophosgene monomer, a red liquid, the photodimer, an example of a 1,3-dithietane, is a colourless solid.

Thisphosgene decomposes at 200 °C or above to form carbon disulfide and carbon tetrachloride.^[7] It has also been observed decomposing to hydrogen sulfide, hydrogen chloride, and carbonyl sulfide gases via contact with human tissue.^{[8][failed verification]}

Toxicology and safety

CSCl₂ is considered highly toxic. Inhalation of the substance can cause irritation of respiratory system, burns, delayed pulmonary edema and death.^[9]

See also

References

Further reading

• 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

This page was last edited on 2 March 2024, at 21:20