Trifluoroacetic acid

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Structural formula
Structure of trifluoroacetic acid
Wedges to clarify the geometry
Surname Trifluoroacetic acid
other names
  • Trifluoroethanoic acid
  • 2,2,2-trifluoroethanoic acid
  • TFA
Molecular formula C 2 HF 3 O 2
Brief description

colorless, pungent smelling liquid

External identifiers / databases
CAS number 76-05-1
EC number 200-929-3
ECHA InfoCard 100,000,846
PubChem 6422
ChemSpider 10239201
Wikidata Q412033
Molar mass 114.02 g mol −1
Physical state



1.48 g cm −3 (20 ° C)

Melting point

−15.25 ° C

boiling point

72.5 ° C

Vapor pressure

130 h Pa (20 ° C)

pK s value



miscible with water, ethanol , acetone and diethyl ether

Refractive index


safety instructions
GHS hazard labeling from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary
05 - Corrosive 06 - Toxic or very toxic


H and P phrases H: 290-331-314-412
EUH: 071
P: 260-273-280-303 + 361 + 353-305 + 351 + 338-312
Thermodynamic properties
ΔH f 0

−1069.9 kJ / mol

As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . Refractive index: Na-D line , 20 ° C

Trifluoroacetic acid (abbreviation: TFA) is a synthetic chemical compound from the group of carboxylic acids . It is a fluorinated derivative of acetic acid , with all three hydrogen atoms of the methyl group being replaced (" substituted ") by fluorine atoms . Their salts and esters are called trifluoroacetates .


Trifluoroacetic acid is formed in the environment through photo-oxidation of the frequently used refrigerant 1,1,1,2-tetrafluoroethane . Trifluoroacetic acid is also formed as an atmospheric breakdown product in almost all synthetic refrigerants of the fourth generation, which are also called HFO or hydrofluoroolefins , such as 2,3,3,3-tetrafluoropropene . It is practically no longer degradable in the environment ( persistent ).


Trifluoroacetic acid is a colorless liquid with a pungent vinegar odor. It is harmful to health when inhaled, causes severe burns and is harmful to aquatic organisms even when diluted. When exposed to heat or ultrasound, trifluoroacetic acid decomposes with the formation of hydrogen fluoride . Strongly exothermic reactions occur with metals (especially light metals ) and alkalis . The reaction of trifluoroacetic acid with lithium aluminum hydride leads to an explosion.

Trifluoroacetic acid is a strong organic acid. It is miscible with water, chlorofluorocarbons and organic solvents . TFA is stable up to 400 ° C; Trifluoroacetic acid is stable up to approx. 200 ° C under oxygen. Your pK s value is 0.23. The big difference of the pK s -value , compared to acetic acid, comes through the electron-withdrawing effect of the fluorine atoms about, is stabilized whereby the acid anion.


Trifluoroacetic acid is used in biotechnology as a solvent for proteins . The further treatment of this solution is problematic. On a larger scale, TFA must be recovered in view of environmental regulations (e.g. through distillation).

Individual evidence

  1. a b c d e f g h Entry on trifluoroacetic acid in the GESTIS substance database of the IFA , accessed on January 10, 2017(JavaScript required) .
  2. a b pKa Data , Compiled by R. Williams (PDF, 78 kB).
  3. a b Entry on trifluoroacetic acid. In: Römpp Online . Georg Thieme Verlag, accessed on May 20, 2014.
  4. Entry on trifluoroacetic acid in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
  5. David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Standard Thermodynamic Properties of Chemical Substances, pp. 5-21.
  6. ^ EH Christoph: Balancing and biomonitoring of trifluoroacetate and other halogen acetates , dissertation, 2002, University of Bayreuth
  7. Data sheet trifluoroacetic acid (PDF) from Merck , accessed on January 19, 2011.
  8. F. Swarts, Bull. Acad. R. Belg. Classe Sci. 8, 343, 1922
  9. Joseph J. Katz: Anhydrous Trifluoroacetic Acid as a Solvent for Proteins . In: Nature . tape 174 , no. 4428 , September 11, 1954, pp. 509-509 , doi : 10.1038 / 174509a0 .

Web links

Wiktionary: Trifluoroacetic acid  - explanations of meanings, word origins, synonyms, translations