Trifluoroacetic acid

• Trifluoroacetic acid
• TFA

Colorless, pungent -smelling fluid

Liquid

1.48 g · cm -3 ( 20 ° C)

-15 ° C

72 ° C.

110 hPa ( 20 ° C)

0.23

Miscible with water, ethanol, acetone and diethyl ether

1.2855

Risk

-1069.9 KJ / mol

Template: Infobox chemical / molecular formula search available

Trifluoroacetic acid (abbreviated as TFA) is a synthetic chemical compound from the group of carboxylic acids. Is a fluorinated derivative of acetic acid, wherein all three hydrogen atoms of the methyl group is replaced by fluorine atoms ( "substituted" ) is. Its salts are called trifluoroacetate.

Occurrence

Trifluoroacetic acid occurs in the environment, among other things by photooxidation of the refrigerant used is often 1,1,1,2- tetrafluoroethane. It is in the environment virtually no longer degradable ( persistent).

Properties

Trifluoroacetic acid is a colorless liquid with a pungent vinegar smell. It is harmful if inhaled, causes severe burns and is harmful to aquatic organisms even in dilution. In the heat or ultrasound to trifluoroacetic acid decomposes to form hydrogen fluoride. Strong exothermic reactions occur (especially light metals ) and bases with metals. 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 hydrochlorofluorocarbons, and organic solvents. TFA is stable up to 400 ° C; oxygen trifluoroacetic acid is stable to about 200 ° C. Your pKa is 0.23. The large difference in pKa value as compared to the acetic acid, is concluded by the electron-withdrawing effect of the fluorine atoms, so that the acid anion is stabilized.

Use

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