Trifluoroacetic acid
From Wikipedia, the free encyclopedia
| Trifluoroacetic acid | |
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| IUPAC name | Trifluoroacetic acid |
| Other names | Perfluoroacetic acid Trifluoroethanoic acid TFA |
| Identifiers | |
| CAS number | [76-05-1] |
| RTECS number | AJ9625000 |
| SMILES | FC(F)(F)C(O)=O |
| Properties | |
| Molecular formula | C2HF3O2 |
| Molar mass | 114.03 g/mol |
| Appearance | colorless liquid |
| Density | 1.5351 g/cm3, 20 °C |
| Melting point |
-15.4 °C; 257.75 K |
| Boiling point |
72.4 °C; 345.55 K |
| Solubility in water | miscible |
| Acidity (pKa) | 0.3 |
| Hazards | |
| MSDS | External MSDS |
| Main hazards | Highly corrosive |
| NFPA 704 |
 1
3
1
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| R-phrases | R20 R35 R52/53 |
| S-phrases | S9 S26 S27 S28 S45 S61 |
| Flash point | -3 °C |
| Related compounds | |
| Related compounds | Acetic acid Trichloroacetic acid |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
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Trifluoroacetic acid (TFA) is the chemical compound with the formula CF3CO2H. It is a strong carboxylic acid due to the influence of the three very electronegative fluorine atoms. Relative to acetic acid, TFA is almost 100,000-fold more acidic. TFA is widely used in organic chemistry.
[edit] Uses
TFA is a reagent used frequently in organic synthesis because of a combination of convenient properties: volatility, solubility in organic solvents, and its strength.[1] It is also less oxidizing than sulfuric acid but more readily available in anhydrous form than hydrochloric acid. One complication to its use is that TFA forms an azeotrope with water with a boiling point of 105 °C.
It is also frequently used as a buffer in liquid chromatography for separation of organic compounds, particularly peptides and small proteins. It is a versatile solvent for NMR spectroscopy (for materials stable in acid).
The derived acid anhydride, [CF3C(O)]2O, is a common reagent for introducing the trifluoracetyl group.
[edit] Synthesis
Electrofluorination of acetic acid with the Simons method is the best way to obtain trifluoroacetic acid. The anodic reaction of the electrolysis of a mixture of hydrogen fluoride and acetic acid below the voltage at which elemental fluorine (F2) develops is a mild reaction which leaves the carboxylic group intact.
[edit] References
- ^ Eidman, K. F.; Nichols, P. J. "Trifluoroacetic Acid" in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. doi:10.1002/047084289
