Trifluoroacetic anhydride
<templatestyles src="Chembox/styles.css"/>
Template:Chembox image cellTemplate:Chembox image cellTemplate:Chembox AllOtherNamesTemplate:Chembox headerbarTemplate:Chembox IndexlistTemplate:Chembox JmolTemplate:Chembox ChEMBLTemplate:Chembox ECHATemplate:Chembox E numberTemplate:Chembox IUPHAR ligandTemplate:Chembox UNIITemplate:Chembox CompToxTemplate:Chembox headerbarTemplate:Chembox SolubilityInWaterTemplate:Chembox HazardsTemplate:Chembox Datapage checkTemplate:Yesno| Template:Longitem | Template:Unbulleted list |
| ChEBI | Template:Unbulleted list |
| ChemSpider | Template:Unbulleted list |
| DrugBank | Template:Unbulleted list |
| EC Number | Template:Unbulleted list |
| KEGG | Template:Unbulleted list |
| Template:Longitem | Template:Unbulleted list |
| RTECS number | Template:Unbulleted list |
| Script error: No such module "collapsible list". | |
| Script error: No such module "collapsible list". | |
| Template:Longitem | Template:Chembox Elements/molecular formula |
| Molar mass | Template:Chem molar mass |
| Appearance | colorless liquid |
| Density | 1.511 g/mL (20°C) |
| Melting point | Template:Chembox CalcTemperatures |
| Boiling point | Template:Chembox CalcTemperatures |
| Solubility | soluble in benzene, dichloromethane, ether, DMF, THF, acetonitrile |
Template:Chembox Footer/tracking container onlyScript error: No such module "TemplatePar".Template:Short description
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.[1] The dehydration might also be carried out with excess α-halogenated acid chlorides. For example, with dichloroacetyl chloride:[2]
- 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.[1]
Similar to acetic anhydride, trifluoroacetic anhydride can be used as a dehydrating agent and as an activator for the Pummerer rearrangement.[3]
It can be used in place of oxalyl chloride in the Swern oxidation, allowing temperatures up to −30 °C.[4]
With sodium iodide, it reduces sulfoxides to sulfides.[3]
Trifluoroacetic anhydride is the recommended desiccant for trifluoroacetic acid.[5]
References
- ↑ a b Script error: No such module "Citation/CS1".
- ↑ <templatestyles src="Citation/styles.css"/>Template:Citation/make link, Amiet, Louis & Disdier, Camille, "Process for the preparation of trifluoroacetic anhydride", published Script error: No such module "auto date formatter"., assigned to Rhone Poulenc Specialites ChimiquesScript error: No such module "Check for unknown parameters".
- ↑ a b Script error: No such module "citation/CS1".
- ↑ Script error: No such module "Citation/CS1".
- ↑ Script error: No such module "citation/CS1".