Trichloroacetic acid
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| Names | |||
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IUPAC name
Trichloroacetic acid
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| Identifiers | |||
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3D model (Jmol)
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| ChemSpider | |||
| ECHA InfoCard | 100.000.844 | ||
| KEGG | |||
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PubChem CID
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| RTECS number | AJ7875000 | ||
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| Properties | |||
| C2HCl3O2 | |||
| Molar mass | 163.38 g·mol−1 | ||
| Appearance | Colorless to white, crystalline solid | ||
| Odor | sharp, pungent | ||
| Density | 1.63 g/cm3 | ||
| Melting point | 57 to 58 °C (135 to 136 °F; 330 to 331 K) | ||
| Boiling point | 196 to 197 °C (385 to 387 °F; 469 to 470 K) | ||
| Soluble in 0.1 parts | |||
| Vapor pressure | 1 mmHg (51.1°C) | ||
| Acidity (pKa) | 0.66 | ||
| -73.0·10−6 cm3/mol | |||
| Structure | |||
| 3.23 D | |||
| Hazards | |||
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EU classification (DSD)
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Corrosive (C) Dangerous for the environment (N) |
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| R-phrases | R35, R50/53 | ||
| S-phrases |
(S1/2), S26, S36/37/39, S45, S60, S61 |
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| NFPA 704 | |||
| Lethal dose or concentration (LD, LC): | |||
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LD50 (median dose)
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5000 mg/kg orally in rats | ||
| US health exposure limits (NIOSH): | |||
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PEL (Permissible)
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none | ||
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REL (Recommended)
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TWA 1 ppm (7 mg/m3) | ||
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IDLH (Immediate danger)
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N.D. | ||
| Related compounds | |||
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Related chloroacetic acids
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Chloroacetic acid Dichloroacetic acid |
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Related compounds
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Acetic acid Trifluoroacetic acid Tribromoacetic acid |
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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 (what is   ?) |
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| Infobox references | |||
Trichloroacetic acid (TCA; TCAA; also known as trichloroethanoic 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.
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.
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 (such as chemical peels and tattoo removal) 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.
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.
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