Trichloroacetic acid


Trichloroacetic acid is an analogue of acetic acid in which the three hydrogen atoms of the methyl group have all been replaced by chlorine atoms. Salts and esters of trichloroacetic acid are called trichloroacetates.

Synthesis

It is prepared by the reaction of chlorine with acetic acid in the presence of a suitable catalyst.
Another route to trichloroacetic acid is the oxidation of trichloroacetaldehyde.

Use

It is widely used in biochemistry for the precipitation of macromolecules, such as proteins, DNA, and RNA. TCA and DCA are both used in cosmetic treatments and as topical medication for chemoablation of warts, including genital warts. It can kill normal cells as well. It is considered safe for use for this purpose during pregnancy.
Its sodium salt was used as an herbicide starting in the 1950s but regulators removed it from the market in the late 1980s and early 1990s.

History

The discovery of trichloroacetic acid by Jean-Baptiste Dumas in 1839 delivered a striking example to the slowly evolving theory of organic radicals and valences. The theory was contrary to the beliefs of Jöns Jakob Berzelius, starting a long dispute between Dumas and Berzelius.