Triphosgene

Triphosgene (bis(trichloromethyl) carbonate (BTC) is a chemical compound with the formula OC(OCCl3)2. It is used as a solid substitute for phosgene, which is a gas and diphosgene, which is a liquid.[5][6] Triphosgene is stable up to 200 °C.[7] Triphosgene is used in a variety of halogenation reactions.[8]

Triphosgene
Names
Preferred IUPAC name
Bis(trichloromethyl) carbonate
Other names
BTC
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.046.336
UNII
  • InChI=1S/C3Cl6O3/c4-2(5,6)11-1(10)12-3(7,8)9 checkY
    Key: UCPYLLCMEDAXFR-UHFFFAOYSA-N checkY
  • InChI=1/C3Cl6O3/c4-2(5,6)11-1(10)12-3(7,8)9
    Key: UCPYLLCMEDAXFR-UHFFFAOYAA
  • ClC(Cl)(Cl)OC(=O)OC(Cl)(Cl)Cl
Properties
C3Cl6O3
Molar mass 296.748 g/mol
Appearance white solid
Density 1.780 g/cm3
Melting point 80 °C (176 °F; 353 K)
Boiling point 206 °C (403 °F; 479 K)
Reacts
Solubility *soluble in dichloromethane[1]
  • soluble in THF[2]
  • soluble in toluene[3]
Hazards
GHS labelling:
GHS06: ToxicGHS05: Corrosive[4]
Danger
H314, H330[4]
P260, P280, P284, P305+P351+P338, P310[4]
Safety data sheet (SDS) SDS Triphosgene
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)
Infobox references

Preparation

This compound is commercially available. It is prepared by exhaustive free radical chlorination of dimethyl carbonate:[6]

CH3OCO2CH3 + 6 Cl2 → CCl3OCO2CCl3 + 6 HCl

Triphosgene can be easily recrystallized from hot hexanes.

Uses

Triphosgene is used as a reagent in organic synthesis as a source of CO2+. It behaves like phosgene, to which it cracks thermally:

OC(OCCl3)2 ⇌ 3 OCCl2

Alcohols are converted to carbonates. Primary and secondary amines are converted to ureas and isocyanates.[6][7][9][10]

Triphosgene has been used to synthesize chlorides.[8] Some Alkyl chlorides are prepared by treating alcohols with a mixture of triphosgene and pyridine. Alkyl dichlorides and trichlorides can similarly be synthesized using triphosgene. Vinyl chlorides are synthesized from ketones using triphosgene and DMF to form a Vilsmeier reagent, followed by a ring opening by chloride ions. Aryl chlorides can also be produced using a Vilsmeier reagent from triphosgene and DMF.

Safety

Triphosgene's low vapor pressure makes it possible for it to reach concentrations that are considered toxicologically unsafe.[11] While several properties of triphosgene are not yet readily available, it is known that it is very toxic if inhaled. A toxic gas is emitted if it comes in contact with water.[12] There is a lack of information and variability regarding the proper handling of triphosgene. It is assumed to have the same risks as phosgene.[13][14]

See also

References
  1. Ouimet MA, Stebbins ND, Uhrich KE (August 2013). "Biodegradable coumaric acid-based poly(anhydride-ester) synthesis and subsequent controlled release". Macromolecular Rapid Communications. 34 (15): 1231–1236. doi:10.1002/marc.201300323. PMC 3789234. PMID 23836606.
  2. Tang S, Ikai T, Tsuji M, Okamoto Y (January 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 Y, Gong R, Miao W (September 2006). "New Method of Synthesizing N-Alkoxycarbonyl-N-arylamide with Triphosgene". Synthetic Communications. 36 (18): 2661–2666. doi:10.1080/00397910600764675. S2CID 98578315.
  4. Sigma-Aldrich Co., Triphosgene.
  5. Roestamadji, Juliatiek; Mobashery, Shahriar (2001). "Bis(trichloromethyl) Carbonate". Encyclopedia of Reagents for Organic Synthesis. doi:10.1002/047084289X.rb200. ISBN 0471936235.
  6. Heiner Eckert; Barbara Forster (1987). "Triphosgene, a Crystalline Phosgene Substitute". Angew. Chem. Int. Ed. Engl. 26 (9): 894–895. doi:10.1002/anie.198708941.
  7. Akiba T, Tamura O, Terashima S (1998). "(4R,5S)-4,5-Diphenyl-3-Vinyl-2-Oxazolidinone". Organic Syntheses. 75: 45. doi:10.15227/orgsyn.075.0045.
  8. Ganiu MO, Nepal B, Van Houten JP, Kartika R (November 2020). "A decade review of triphosgene and its applications in organic reactions". Tetrahedron. 76 (47): 131553. doi:10.1016/j.tet.2020.131553. PMC 8054975. PMID 33883783.
  9. Tsai JH, Takaoka LR, Powell NA, Nowick JS (2002). "Synthesis of Amino Acid Ester Isocyanates: Methyl (S)-2-Isocyanato-3-Phenylpropanoate". Organic Syntheses. 78: 220. doi:10.15227/orgsyn.078.0220.
  10. Du H, Zhao B, Shi Y (2009). "Pd(0)-Catalyzed Diamination of Trans-1-Phenyl-1,3-Butadiene with Di-tert-Butyldiaziridinone as Nitrogen Source". Organic Syntheses. 86: 315. doi:10.15227/orgsyn.086.0315.
  11. Cotarca L, Geller T, Répási J (2017-09-15). "Bis(trichloromethyl)carbonate (BTC, Triphosgene): A Safer Alternative to Phosgene?". Organic Process Research & Development. 21 (9): 1439–1446. doi:10.1021/acs.oprd.7b00220.
  12. "Material Safety Data Sheet: Triphosgene" (PDF). Acros Organics. 2009. Retrieved February 17, 2022.
  13. Damle SB (February 1993). "Safe handling of diphosgene, triphosgene". Chemical & Engineering News. 71 (6): 4.
  14. Pauluhn J (February 2021). "Phosgene inhalation toxicity: Update on mechanisms and mechanism-based treatment strategies". Toxicology. 450: 152682. doi:10.1016/j.tox.2021.152682. PMID 33484734. S2CID 231693591.
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