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Triphosgene (bis(trichloromethyl) carbonate (BTC), C3Cl6O3) is a chemical compound that is used as a safer substitute for phosgene, because, at room temperature, it is a solid crystal, as opposed to phosgene, which is a gas.[5] Triphosgene crystals decompose above 200 °C.[6]

Triphosgen Strukturformel.svg
Preferred IUPAC name
Bis(trichloromethyl) carbonate
Other names
3D model (JSmol)
ECHA InfoCard 100.046.336
Molar mass 296.748 g/mol
Appearance white crystals
Density 1.780 g/cm3
Melting point 80 °C (176 °F; 353 K)
Boiling point 206 °C (403 °F; 479 K)
Solubility *soluble in dichloromethane[1]
  • soluble in THF[2]
  • soluble in toluene[3]
Safety data sheet SDS Triphosgene
GHS pictograms GHS-pictogram-skull.svgGHS-pictogram-acid.svg[4]
GHS signal word Danger
H314, H330[4]
P260, P280, P284, P305+351+338, P310[4]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references


This compound is commercially available. It is prepared by exhaustive free radical chlorination of dimethyl carbonate:[5]

CH3OCO2CH3 + 6 Cl2 → CCl3OCO2CCl3 + 6 HCl

Triphosgene can be easily recrystallized from boiling hexanes to yield pure white crystals.


Triphosgene is used as a reagent in organic synthesis and is a less hazardous substitute for phosgene for a variety of chemical transformations including to bond one carbonyl group to two alcohols, and to convert an amine group into isocyanate.[5]


The toxicity of triphosgene is the same as phosgene since it decomposes to phosgene on heating and upon reaction with nucleophiles. Even trace moisture leads to formation of phosgene. Therefore, this reagent can be safely handled if one takes all the precautions as for phosgene.[7]

See alsoEdit


  1. ^ Michelle A. Ouimet, Nicholas D. Stebbins, Kathryn E. Uhrich (2013). "Biodegradable Coumaric Acid-Based Poly(anhydride-ester) Synthesis and Subsequent Controlled Release". Macromol. Rapid Commun. 34 (15): 1231–1236. doi:10.1002/marc.201300323. PMC 3789234. PMID 23836606.CS1 maint: multiple names: authors list (link)
  2. ^ Tang, Shouwan; Ikai, Tomoyuki; Tsuji, Masashi; Okamoto, Yoshio (2010). "Immobilization and chiral recognition of 3,5-dimethylphenylcarbamates of cellulose and amylose bearing 4-(trimethoxysilyl)phenylcarbamate groups". Chirality. 22 (1): 165–172. doi:10.1002/chir.20722. PMID 19455617.
  3. ^ Zhou, Yuhan; Gong, Runjun; Miao, Weirong (2006-09-01). "New Method of Synthesizing N‐Alkoxycarbonyl‐N‐arylamide with Triphosgene". Synthetic Communications. 36 (18): 2661–2666. doi:10.1080/00397910600764675. ISSN 0039-7911.
  4. ^ a b c Sigma-Aldrich Co., Triphosgene. Retrieved on 2018-06-12.
  5. ^ a b c Dr. Heiner Eckert; Dr. Barbara Forster (1987). "Triphosgene, a Crystalline Phosgene Substitute". Angew. Chem. Int. Ed. Engl. 26 (9): 894–895. doi:10.1002/anie.198708941.
  6. ^ Dr. Heiner Eckert (2011). "Phosgenation Reactions with Phosgene from Triphosgene". Chim. Oggi Chem. Today. 29 (6): 40–46.
  7. ^ Suresh B. Damle (1993-02-08). "Safe handling of diphosgene, triphosgene". Chemical & Engineering News. 71 (6): 4.

External linksEdit