Trichloroacetic acid

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Trichloroacetic acid
Trichloroacetic-acid-2D-skeletal.png Trichloroacetic-acid-3D-vdW.png
Trichloroacetic-acid-elpot.png
Identifiers
CAS number 76-03-9 YesY
PubChem 6421
KEGG C11150 YesY
ChEMBL CHEMBL14053
RTECS number AJ7875000
Jmol-3D images Image 1
Properties
Molecular formula C2HCl3O2
Molar mass 163.39 g mol−1
Appearance White solid
Density 1.63 g/cm³
Melting point 57 to 58 °C (135 to 136 °F; 330 to 331 K)[1]
Boiling point 196 to 197 °C (385 to 387 °F; 469 to 470 K)[1]
Solubility in water Soluble in 0.1 parts[1]
Acidity (pKa) 0.66[2]
Structure
Dipole moment 3.23 D
Hazards
EU classification Corrosive (C)
Dangerous for
the environment (N)
R-phrases R35, R50/53
S-phrases (S1/2), S26, S36/37/39,
S45, S60, S61
NFPA 704
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g., canola oil Health code 3: Short exposure could cause serious temporary or residual injury. E.g., chlorine gas Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
LD50 5000 mg/kg orally in rats[1]
Related compounds
Related chloroacetic acids Chloroacetic acid
Dichloroacetic acid
Related compounds Acetic acid
Trifluoroacetic acid
Tribromoacetic acid
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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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as trichloroethanoic acid) is an analogue of acetic acid in which the three hydrogen atoms of the methyl group have all been replaced by chlorine atoms.

It is prepared by the reaction of chlorine with acetic acid in the presence of a suitable catalyst.

CH
3
COOH
+ 3Cl
2
CCl
3
COOH
+3HCl

It is widely used in biochemistry for the precipitation of macromolecules, such as proteins, DNA, and RNA. Its sodium salt is used as a weedkiller. Solutions containing trichloroacetic acid as an ingredient are used for cosmetic treatments, such as chemical peels, tattoo removal, and the treatment of warts, including genital warts. It can kill normal cells as well. It is considered safe for use for this purpose during pregnancy.[3]

Salts and esters of trichloroacetic acid are called trichloroacetates. Reduction of trichloroacetic acid results in dichloroacetic acid, a pharmacologically active compound that shows promise for the treatment of cancer.[4]

History[edit]

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.[5] The theory was contrary to the beliefs of Jöns Jakob Berzelius, starting a long dispute between Dumas and Berzelius.[6]

See also[edit]

References[edit]

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