Triphosgene

Triphosgene (bis(trichloromethyl) carbonate (BTC) is a chemical compound with the formula OC(OCCl3)2. It is used as a safer substitute for phosgene, because, at room temperature, it is a solid, whereas phosgene is a gas.[5] Triphosgene decomposes above 200 °C.[6]

Triphosgene
Names
Preferred IUPAC name
Bis(trichloromethyl) carbonate
Other names
BTC
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.046.336
UNII
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
Safety data sheet SDS Triphosgene
GHS pictograms [4]
GHS Signal word Danger
GHS hazard statements
 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).
N verify (what is YN ?)
Infobox references

Preparation

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 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 isocyanate.[5][7][8][9]

Safety

The toxicity of triphosgene and phosgene are the same since the trimer decomposes to phosgene on heating and upon reaction with nucleophiles. Trace moisture leads to formation of phosgene. Therefore, this reagent can be safely handled if one takes all the precautions as for phosgene.[10]

See also

References
  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. Sigma-Aldrich Co., Triphosgene. Retrieved on 2018-06-12.
  5. 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. 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. Tsai, James H.; Takaoka, Leo R.; Powell, Noel A.; Nowick, James S. (2002). "Synthesis of Amino Acid Ester Isocyanates: Methyl (S)-2-Isocyanato-3-Phenylpropanoate". Organic Syntheses. 78: 220. doi:10.15227/orgsyn.078.0220.
  9. Du, Haifeng; Zhao, Baoguo; Shi, Yian (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.
  10. Suresh B. Damle (1993-02-08). "Safe handling of diphosgene, triphosgene". Chemical & Engineering News. 71 (6): 4.
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