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.[1][2] Triphosgene is stable up to 200 °C.[3] Triphosgene is used in a variety of halogenation reactions.[4]
Preparation
This compound is commercially available. It is prepared by exhaustive free radical chlorination of dimethyl carbonate:[2]
- 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:
Alcohols are converted to carbonates. Primary and secondary amines are converted to ureas and isocyanates.[2][3][5][6]
Triphosgene has been used to synthesize chlorides.[4] 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
The vapor pressure of Triphosgene is sufficiently high for it to reach concentrations that are considered toxicologically unsafe.[7] 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.[8] There is a lack of information and variability regarding the proper handling of triphosgene. It is assumed to have the same risks as phosgene.[9][10]
See also
References
<templatestyles src="Reflist/styles.css" />
- ↑ Script error: No such module "citation/CS1".
- ↑ a b c Script error: No such module "Citation/CS1".
- ↑ a b Script error: No such module "Citation/CS1".
- ↑ a b Script error: No such module "Citation/CS1".
- ↑ Script error: No such module "Citation/CS1".
- ↑ Script error: No such module "Citation/CS1".
- ↑ Script error: No such module "Citation/CS1".
- ↑ Script error: No such module "citation/CS1".
- ↑ Script error: No such module "Citation/CS1".
- ↑ Script error: No such module "Citation/CS1".
Script error: No such module "Check for unknown parameters".