thiophosgene

Typically, {{chem2|CSCl2}} is prepared in a two-step process from carbon disulfide. In the first step, carbon disulfide is chlorinated to give trichloromethanesulfenyl chloride ({{chem2|CCl3SCl}}), a rare sulfenyl chloride:

:{{chem2|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 and hydrolyzes the disulfur dichloride. Reduction of trichloromethanesulfenyl chloride with, e.g., tin{{OrgSyn|last = Dyson|first = G. M.|year = 1926|title = Thiophosgene|volume = 6|pages = 86|doi = 10.15227/orgsyn.006.0086}} or dihydroanthracene{{cite book|title= Acyl Halides|editor=S. Patai|year=1972|doi=10.1002/9780470771273.ch11|series=PATAI'S Chemistry of Functional Groups|chapter=Thiocarbonyl halides|author=K. T. Potts, C. Sapino|pages=349–380|isbn=978-0-470-77127-3}} produces thiophosgene:

:{{chem2|CCl3SCl + M → CSCl2 + MCl2}}

An alternative one-step reaction isGraham-Otto's Ausführliches Lehrbuch der Chemie (in German; 1881). Germany: Vieweg.

:CCl₄ + H₂S → SCCl₂ + 2 HCl

{{chem2|CSCl2}} is mainly used to prepare compounds with the connectivity {{chem2|CSX2}} where X = OR, NHR.Pascual, Roxana Martinez "Thiophosgene" Synlett 2015, vol. 26, pp. 1776-1777.{{doi|10.1055/s-0034-1380659}} Such reactions proceed via intermediate such as CSClX. Under certain conditions, one can convert primary amines into isothiocyanates.

{{chem2|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.{{Cite journal|last1 = Sharma|first1 = S.|title = Thiophosgene in Organic Synthesis|doi = 10.1055/s-1978-24896|journal = Synthesis|volume = 1978|issue = 11|pages = 803–820|year = 1978}}

It forms a head-to-tail dimer upon irradiation with UV light:

:{{chem2|2 CSCl2 → S2(CCl2)2}}

Unlike thiophosgene monomer, a red liquid, the photodimer, an example of a 1,3-dithietane, is a colourless solid.{{cite journal|title=Die Kristall- und Molekelstruktur des dimeren Thiophosgens|author=B. Krebs H. Beyer |journal=Z. Anorg. Allg. Chem.|volume=365|pages=199–210

|year=1969|issue=3–4|doi=10.1002/zaac.19693650315}} Swarts fluorination of the dimer and then cracking is the principal route to thiocarbonyl fluoride.{{cite book|doi=10.1002/9780470771273.ch11|title=The Chemistry of Acyl Halides|editor-first=Saul|editor-last=Patai|series=The Chemistry of Functional Groups|year=1972|publisher=Wiley|chapter=Thiocarbonyl halides|first1=K. T.|last1=Potts|first2=C.|last2=Sapino|pages=354–355|isbn=978-0-471-66936-4 }}

Thiophosgene decomposes at 200 °C or above to form carbon disulfide and carbon tetrachloride.U.S. Coast Guard, Department of Transportation (1999). CHRIS - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office — [https://cameochemicals.noaa.gov/chemical/1601 via] Cameo Chemicals. As [https://pubchem.ncbi.nlm.nih.gov/compound/Thiophosgene#section=Fire-Hazards cited] in "Thiophosgene" PubChem compound record. It has also been observed decomposing to hydrogen sulfide, hydrogen chloride, and carbonyl sulfide gases via contact with human tissue.{{Cite web|url=https://pubchem.ncbi.nlm.nih.gov/compound/Thiophosgene|title=Thiophosgene}}{{failed verification|date=March 2024}}

{{chem2|CSCl2}} is considered highly toxic. Inhalation of the substance can cause irritation of respiratory system, burns, delayed pulmonary edema and death.US National Library of Medicine (2020). Hazardous Substances Databank entry, as [https://pubchem.ncbi.nlm.nih.gov/compound/Thiophosgene#section=Hazards-Summary summarized] on "Thiophosgene" PubChem compound record.

{{Div col}}

• Phosgene
• Carbonyl fluoride
• Sulfur dichloride

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{{reflist}}

• {{Holleman&Wiberg}}

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{{Chemical agents}}

Category:Inorganic carbon compounds

Category:Inorganic sulfur compounds

Category:Thioacyl chlorides

Category:Thiocarbonyl compounds

Category:Thiochlorides