Definition
ChEBI: Trifluoroacetic acid is a monocarboxylic acid that is the trifluoro derivative of acetic acid. It has a role as a reagent and a human xenobiotic metabolite. It derives from an acetic acid. It is a conjugate acid of a trifluoroacetate.
General Description
Trifluoroacetic acid appears as a colorless fuming liquid with a pungent odor. Soluble in water and denser than water. Corrosive to skin, eyes and mucous membranes. Used to make other chemicals and as a solvent.
Air & Water Reactions
Fumes in air. Soluble in water.
Reactivity Profile
Trifluoroacetic acid(76-05-1) is a strong acid; attacks many metals [Handling Chemicals Safely 1980. p. 935]. A 30% solution of hydrogen peroxide in Trifluoroacetic acid(76-05-1) is often used to destructively oxidize aromatic rings in preference to the side chains. Explosions have occurred, if the excess peroxide is not catalytically destroyed, prior to removal of solvent, [Tetrahedron Lett., 1977, 1703-1704]. The reduction of amides of Trifluoroacetic acid(76-05-1) with lithium aluminum hydride are dangerous at all phases of the process, explosions have occurred, [Chem. Eng. News, 1955, 33, 1368].
Health Hazard
Trifluoroacetic acid is a highly corrosive substance. Contact of the liquid with the skin, eyes, and mucous membranes can cause severe burns, and ingestion can result in serious damage to the digestive tract. TFA vapor is highly irritating of the eyes and respiratory tract, and inhalation of high concentrations can lead to severe destruction of the upper respiratory tract and may be fatal as a result of pulmonary edema. Symptoms of overexposure to TFA vapor include a burning feeling, coughing, headache, nausea, and vomiting.
Trifluoroacetic acid has not been found to be carcinogenic or to show reproductive or developmental toxicity in humans.
Fire Hazard
Trifluoroacetic acid is not combustible. Nevertheless, the presence of trifluoroacetic acid at the site of a fire would be of great concern because of its high vapor pressure and extreme corrosiveness. Some are oxidizers and may ignite combustibles (wood, paper, oil, clothing, etc.). Contact with metals may evolve flammable hydrogen gas. Containers may explode when heated.
Biochem/physiol Actions
Trifluoroacetic acid?(TFA) is mainly preferred as an internal chemical shift referencing agent in?19F NMR.
storage
trifluoroacetic acid should be
stored in an acid cabinet away from other classes of compounds. Because of its high
vapor pressure, fumes of trifluoroacetic acid can destroy labels on other bottles if the
container is not tightly sealed.
Purification Methods
The purification of trifluoroacetic acid, reported in earlier editions of this work, by refluxing over KMnO4 for 24hours and slowly distilling has resulted in very SERIOUS EXPLOSIONS on various occasions, but not always. This apparently depends on the source and/or age of the acid. The method is NOT RECOMMENDED. Water can be removed by adding trifluoroacetic anhydride (0.05%, to diminish water content) and distilling. [Conway & Novak J Phys Chem 81 1459 1977]. It can be refluxed and distilled from P2O5. It is further purified by fractional crystallisation by partial freezing and again distilled. Highly TOXIC vapour. Work in an efficient fume hood. [Beilstein 2 IV 458.]
Incompatibilities
Mixing trifluoroacetic acid and water evolves considerable heat.
Waste Disposal
Trifluoroacetic acid and waste material containing this substance should be placed in an appropriate
container, clearly labeled, and handled according to your institution's waste disposal guidelines.