2,4,6-Trichloroanisole

2,4,6-Trichloroanisole (TCA) is an organic compound with the formula CH₃OC₆H₂Cl₃. It is the symmetric isomer of trichloroanisole. It is a colorless solid.

2,4,6-Trichloroanisole

Names
Preferred IUPAC name 1,3,5-Trichloro-2-methoxybenzene
Other names 2,4,6-Trichloroanisole TCA 2,4,6-Trichloromethoxybenzene
Identifiers
CAS Number	87-40-1 Y
3D model (JSmol)	Interactive image Interactive image
ChEBI	CHEBI:19333 Y
ChemSpider	6620 Y
ECHA InfoCard	100.001.585
EC Number	201-743-5
KEGG	C11510 Y
PubChem CID	6884
RTECS number	MFCD00000588
UNII	31O3X41254 Y
CompTox Dashboard (EPA)	DTXSID9073886
InChI InChI=1S/C7H5Cl3O/c1-11-7-5(9)2-4(8)3-6(7)10/h2-3H,1H3 Y Key: WCVOGSZTONGSQY-UHFFFAOYSA-N Y InChI=1/C7H5Cl3O/c1-11-7-5(9)2-4(8)3-6(7)10/h2-3H,1H3 Key: WCVOGSZTONGSQY-UHFFFAOYAT
SMILES COc1c(Cl)cc(Cl)cc1Cl Clc1cc(Cl)cc(Cl)c1OC
Properties
Chemical formula	C7H5Cl3O
Molar mass	211.47 g·mol−1
Melting point	60 to 62 °C (140 to 144 °F; 333 to 335 K)
Boiling point	140 °C (284 °F; 413 K) at 28 Torr
Hazards
GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H302, H319, H413
Precautionary statements	P264, P270, P273, P280, P301+P312, P305+P351+P338, P330, P337+P313, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Occurrence

2,4,6-Trichloroanisole represents one of the strongest of off-flavors, substances "generated naturally in foods/beverages [that considerably] deteriorate the quality" of such products.^[1][2] It is also a component of some drinking waters.^[3] It has also been detected in blood samples.^[4]

Wine

As of 2000, TCA was considered the primary chemical compound responsible for the phenomenon of cork taint in wines,^[5][1] and it has an unpleasant earthy, musty and moldy smell.^[2]

Coffee

TCA has also been suggested as cause of the "Rio defect" in coffees from Brazil and other parts of the world,^[6] which refers to a taste described as "medicinal, phenolic, or iodine-like".^[7] In investigation of the mechanism of its role in producing off-flavor effects, it was found to "attenuate olfactory transduction by suppressing cyclic nucleotide-gated channels, without evoking odorant responses."^[1]

Formation

TCA is formed by the methylation of 2,4,6-trichlorophenol.^[8][7] More generally, it may be produced when naturally occurring airborne fungi and bacteria are presented with chlorinated phenolic compounds, which they then convert into chlorinated anisole derivatives.^[9] Species implicated include those of the genera Aspergillus, Penicillium, Actinomycetes, Botrytis (e.g. Botrytis cinerea), Rhizobium, or Streptomyces.^[10][11][9]

The chlorophenol precursor, 2,4,6-trichlorophenol, is used as a fungicide; more generally, related compounds can originate as contaminants found in some pesticides and wood preservatives, or as by-products of the chlorine bleaching process used to sterilize or bleach wood, paper, and other materials.^[12]

Further reading

• Marsili, R. (2000). "Solid-Phase Microextraction: Food Technology Applications". In Wilson, Ian D. (ed.). Encyclopedia of Separation Science. New Yor, NY: Academic Press. pp. 4178–4190. doi:10.1016/B0-12-226770-2/06791-0. ISBN 9780122267703. Over the last two decades, the incidence of mouldy and musty off-flavours in cork-sealed wines has increased significantly. 2,4,6-Trichloroanisole (TCA) has been identified as the primary chemical responsible for cork taint. The human olfactometry threshold for TCA is 4–10 ng L−1 in white wine and 50 ng L−1 in red wine. In the case of wine, a worldwide loss of roughly US$1 billion per year is attributed to cork taint.
• Science Direct Staff (June 2023). "2-4-6-Trichloroanisole" (Science Direct citation sample/listing). Retrieved June 26, 2023.
• Buser, H.R.; Zanier, C. & Tanner, H. (1982). "Identification of 2,4,6-Trichloroanisole as a Potent Compound Causing Cork Taint in Wine". Journal of Agricultural and Food Chemistry. 30 (2): 359–362. doi:10.1021/jf00110a037.{{cite journal}}: CS1 maint: multiple names: authors list (link) An early primary research report on the role of TCA in cork taint.

See also

• 2,4,6-Tribromoanisole