Trichloroacetic acid

Template:Chembox EUClass

Trichloroacetic acid
Names
Preferred IUPAC name
Trichloroacetic acid
Identifiers
CAS Number
3D model (JSmol)
ChEMBL
ChemSpider
KEGG
PubChem CID
RTECS number
  • AJ7875000
UNII
InChI
  • InChI=1S/C2HCl3O2/c3-2(4,5)1(6)7/h(H,6,7)
    Key: YNJBWRMUSHSURL-UHFFFAOYSA-N
SMILES
  • ClC(Cl)(Cl)C(O)=O
Properties
Chemical formula
 C2HCl3O2
Molar mass 163.38 g·mol−1
Appearance Colorless to white, crystalline solid
Odor sharp, pungent [1]
Density 1.63 g/cm3
Melting point 57 to 58 °C (135 to 136 °F; 330 to 331 K)[2]
Boiling point 196 to 197 °C (385 to 387 °F; 469 to 470 K)[2]
Solubility in water
 1000g/100mL[2]
Vapor pressure 1 mmHg (51.1°C)[1]
Acidity (pKa) 0.66[3]
Magnetic susceptibility (χ)
 -73.0·10−6 cm3/mol
Structure
Dipole moment
 3.23 D
Hazards
R-phrases (outdated) Template:R35, Template:R50/53
S-phrases (outdated) Template:S1/2, S26, Template:S36/37/39,
Template:S45, Template:S60, Template:S61
NFPA 704 (fire diamond)
3
1
0
Lethal dose or concentration (LD, LC):
5000 mg/kg orally in rats[2]
NIOSH (US health exposure limits):
PEL (Permissible)
 none[1]
REL (Recommended)
 TWA 1 ppm (7 mg/m3)[1]
IDLH (Immediate danger)
 N.D.[1]
Related compounds
Related chloroacetic acids
 Chloroacetic acid
Dichloroacetic acid
Related compounds
 Acetic acid
Trifluoroacetic acid
Tribromoacetic acid
Except where otherwise noted, 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as trichloroethanoic acid) is an analogue of acetic acid in which the three hydrogen atoms of the methyl group have all been replaced by chlorine atoms. 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 such as red phosphorus. This reaction is Hell–Volhard–Zelinsky halogenation.

CH
3COOH + 3 Cl
2 → CCl
3COOH + 3 HCl

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 (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.[4][5] The sodium salt (sodium trichloroacetate) was used as an herbicide starting in the 1950s but regulators removed it from the market in the late 1980s and early 1990s.[6][7][8][9]

  • Trichloracetic acid for TCA CROSS procedures
    Trichloracetic acid for TCA CROSS procedures
  • Applying trichloracetic acid for TCA CROSS procedures
    Applying trichloracetic acid for TCA CROSS procedures
  • Frosting after applying trichloracetic acid in TCA CROSS procedure
    Frosting after applying trichloracetic acid in TCA CROSS procedure

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.[10] The theory was contrary to the beliefs of Jöns Jakob Berzelius, starting a long dispute between Dumas and Berzelius.[11]

See also

  • Chloroacetic acids

References

  1. 1 2 3 4 5 NIOSH Pocket Guide to Chemical Hazards #0626National Institute for Occupational Safety and Health (NIOSH)
  2. 1 2 3 4 Budavari, Susan, ed. (1996), The Merck Index: An Encyclopedia of Chemicals, Drugs, and Biologicals (12th ed.), Merck, ISBN 0911910123
  3. ↑ Databog fysik kemi, F&K Forlaget 11. udgave 2009
  4. ↑ "Trichloroacetic Acid or Bichloroacetic Acid for Genital Warts (Human Papillomavirus)". WebMD. Archived from the original on 2015-07-16. Retrieved 2021-04-27.
  5. ↑ Wiley DJ, Douglas J, Beutner K, Cox T, Fife K, Moscicki AB, Fukumoto L (2002). "External genital warts: Diagnosis, treatment, and prevention". Clinical Infectious Diseases. 35 (Suppl 2): S210–S224. doi:10.1086/342109. PMID 12353208.
  6. ↑ TCA-sodium in the Pesticide Properties DataBase (PPDB), accessed June 20, 2014
  7. ↑ G. S. Rai and C. L. Hamner Persistence of Sodium Trichloroacetate in Different Soil Types Archived 2020-07-20 at the Wayback Machine Weeds 2(4) Oct. 1953: 271-279
  8. ↑ OECD Trichloroacetic Acid CAS N°: 76-03-9 Archived 2016-03-04 at the Wayback Machine Accessed June 20, 2014
  9. ↑ EPA December 1991. trichloroacetic acid (TCA) EPA Cancellation 12/91 Archived 2020-08-15 at the Wayback Machine Accessed June 20, 2014
  10. ↑ Dumas (1839). "Trichloroacetic acid". Annalen der Pharmacie. 32: 101–119. doi:10.1002/jlac.18390320109. Archived (PDF) from the original on 2021-08-29. Retrieved 2021-04-27.
  11. ↑ William Albert Noyes (1927). "Valence". Proceedings of the American Philosophical Society. 66: 287–308. JSTOR 3301070.
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