Trichloroacetic acid

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Trichloroacetic acid
Trichloroacetic acid structural formula.png
IUPAC name
Trichloroethanoic acid
Other names
Trichloracetic acid
Jmol-3D images Image
Molar mass 163.38 g/mol
Appearance Colorless crystals
Odor Odorless
Density 1.63 g/cm3
Melting point 57.5 °C (135.5 °F; 330.6 K)
Boiling point 195.5 °C (383.9 °F; 468.6 K)
8.17 g/100 ml (20 °C)
Solubility Miscible with acetone, alcohols, benzene, diethyl ether, methanol
Slightly soluble in carbon tetrachloride
Solubility in acetone 850 g/100 g (25 °C)
Solubility in benzene 201 g/100 g (25 °C)
Solubility in diethyl ether 617 g/100 g (25 °C)
Solubility in methanol 2143 g/100 g (25 °C)
Solubility in xylene 110 g/100 g (25 °C)
Vapor pressure 1 mmHg (51.1 °C)
Acidity (pKa) 0.66
Safety data sheet Sigma-Aldrich
Lethal dose or concentration (LD, LC):
3.320 mg/kg (rat, oral)
Related compounds
Related compounds
Acetic acid
Chloroacetic acid
Dichloroacetic acid
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Trichloroacetic acid or TCA is an organic chemical compound, an analogue of acetic acid in which the three hydrogen atoms of the methyl group have all been replaced by chlorine atoms. It has the chemical formula CCl3COOH.



TCA is a strong acid, which reacts with bases in solution to give salts.

It can decarboxylate in solution to form chloroform, especially as a salt.[1][2][3]


Trichloroacetic acid is a colorless crystalline hygroscopic solid, soluble in water and organic solvents.


Trichloroacetic acid is sold by chemical suppliers. Sometimes it is sold by some dentistry suppliers, usually as a solution.


TCA can be synthesized by complete chlorination of acetic acid, with acetic anhydride as a catalyst, in the presence of UV light. Some sources indicate that sulfur[4] or red phosphorus[5] can also be used as catalysts.

CH3COOH + 3 Cl2 → CCl3COOH + 3 HCl

This reaction also produces acetyl chloride and chloroacetyl chloride as side products, which may be recovered via fractional distillation if desired.




Trichloroacetic acid is corrosive and harmful. Should be handled with proper protection.


Trichloroacetic acid should be kept in closed air-tight bottles, preferably in a desiccator.


Adding an excess base will neutralize the compound. The compound can also be reduced to acetic acid using metallic powders.

Lastly, it can also be strongly diluted in water before being poured down the drain.


  1. Chemplayer, Chloroform from trichloroacetic acid,
  2. F. H. Verhoek, J. Am. Chem. Soc. 1934, 56, 3, 571–577,
  3. G. A. Hall Jr., F. H. Verhoek, J. Am. Chem. Soc. 1947, 69, 3, 613–616,

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