Trifluoroacetic acid

Chembox new
Name = Trifluoroacetic acid
ImageFileL1 = Trifluoroacetic-acid-skeletal.png ImageSizeL1 = 100px
ImageFileR1 = Trifluoroacetic-acid-3D-vdW.png ImageSizeR1 = 120px
ImageFile2 = Trifluoroacetic-acid-elpot.png ImageSize2 = 120px
IUPACName = 1,1,1-Trifluoroethanoic acid
OtherNames = Perfluoroacetic acid
Trifluoroethanoic acid
TFA
Section1 = Chembox Identifiers
SMILES = FC(F)(F)C(O)=O
ChemSpiderID = 10239201
CASNo = 76-05-1
RTECS = AJ9625000
Section2 = Chembox Properties
Formula = C₂HF₃O₂
MolarMass = 114.03 g/mol
Appearance = colorless liquid
Density = 1.5351 g/cm³, 20 °C
Solubility = miscible
MeltingPt = -15.4 °C; 257.75 K
BoilingPt = 72.4 °C; 345.55 K
pKa = 0.3
Viscosity =
Section7 = Chembox Hazards
ExternalMSDS = [http://www.jtbaker.com/msds/englishhtml/t5525.htm External MSDS]
MainHazards = Highly corrosive
NFPA-H = 3
NFPA-R = 1
NFPA-F = 1
FlashPt = -3 °C
RPhrases = R20 R35 R52/53
SPhrases = S9 S26 S27 S28 S45 S61
Section8 = Chembox Related
OtherCpds = Acetic acid
Trichloroacetic acid

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.

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. [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] 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 used as a ion pairing agent 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.

ynthesis

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.

References