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Trifluoroacetic anhydride

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Trifluoroacetic anhydride
Skeletal formula
Ball-and-stick model
Names
Preferred IUPAC name Trifluoroacetic anhydride
Other names
  • 2,2,2-Trifluoroacetic anhydride
  • TFAA
Identifiers
CAS Number
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.006.349 Edit this at Wikidata
EC Number
  • 206-982-9
PubChem CID
UNII
CompTox Dashboard (EPA)
InChI
  • InChI=1S/C4F6O3/c5-3(6,7)1(11)13-2(12)4(8,9)10Key: QAEDZJGFFMLHHQ-UHFFFAOYSA-N
SMILES
  • C(=O)(C(F)(F)F)OC(=O)C(F)(F)F
Properties
Chemical formula C4F6O3
Molar mass 210.031 g·mol
Appearance colorless liquid
Density 1.511 g/mL (20°C)
Melting point −65 °C (−85 °F; 208 K)
Boiling point 40 °C (104 °F; 313 K)
Solubility in water reacts
Solubility soluble in benzene, dichloromethane, ether, DMF, THF, acetonitrile
Hazards
GHS labelling:
Pictograms GHS05: CorrosiveGHS07: Exclamation mark
Signal word Danger
Hazard statements H314, H332
Precautionary statements P280, P305+P351+P338, P310
Safety data sheet (SDS) Oxford MSDS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C , 100 kPa). ☒N verify (what is  ?) Infobox references
Chemical compound

Trifluoroacetic anhydride (TFAA) is the acid anhydride of trifluoroacetic acid. It is the perfluorinated derivative of acetic anhydride.

Preparation

Trifluoroacetic anhydride was originally prepared by the dehydration of trifluoroacetic acid with phosphorus pentoxide. The dehydration might also be carried out with excess α-halogenated acid chlorides. For example, with dichloroacetyl chloride:

2 CF3COOH + Cl2CHCOCl → (CF3CO)2O + Cl2CHCOOH + HCl

Uses

Trifluoroacetic anhydride has various uses in organic synthesis.

It may be used to introduce the corresponding trifluoroacetyl group, for which it is more convenient than the corresponding acyl chloride, trifluoroacetyl chloride, which is a gas.

It can be used to promote reactions of carboxylic acids, including Friedel-Crafts acylation and acylation of other unsaturated compounds. Other electrophilic aromatic substitution reactions can also be promoted with trifluoroacetic anhydride, including nitration, sulfonation and nitrosylation.

Similar to acetic anhydride, trifluoroacetic anhydride can be used as a dehydrating agent and as an activator for the Pummerer rearrangement.

It can be used in place of oxalyl chloride in the Swern oxidation, allowing temperatures up to −30 °C.

With sodium iodide, it reduces sulfoxides to sulfides.

Trifluoroacetic anhydride is the recommended desiccant for trifluoroacetic acid.

References

  1. ^ Sigma-Aldrich Co., Trifluoroacetic Anhydride. Retrieved on 2020-06-08.
  2. ^ Tedder, J. M. (1955). "The Use of Trifluoroacetic Anhydride and Related Compounds in Organic Synthesis". Chem. Rev. 55 (5): 787–827. doi:10.1021/cr50005a001.
  3. US 4595541, Amiet, Louis & Disdier, Camille, "Process for the preparation of trifluoroacetic anhydride", published 1986-06-17, assigned to Rhone Poulenc Specialites Chimiques 
  4. ^ Sweeney, Joseph; Perkins, Gemma; DiMauro, Erin F.; Hodous, Brian L. (2005). "Trifluoroacetic Anhydride". Encyclopedia of Reagents for Organic Synthesis. John Wiley & Sons. doi:10.1002/047084289X.rt237.pub2. ISBN 978-0-470-84289-8.
  5. Omura, Kanji; Sharma, Ashok K.; Swern, Daniel (1976). "Dimethyl Sulfoxide-Trifluoroacetic Anhydride. New Reagent for Oxidation of Alcohols to Carbonyls". J. Org. Chem. 41 (6): 957–962. doi:10.1021/jo00868a012.
  6. Chai, Christina Li Lin; Armarego, W. L. F. (2003). Purification of laboratory chemicals (Google Books excerpt). Oxford: Butterworth-Heinemann. p. 376. ISBN 0-7506-7571-3.
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