Wikipedia

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
Chemical structure of 2,4,6-trichloroanisole
Ball-and-stick model of the 2,4,6-trichloroanisole molecule
Names
Preferred IUPAC name
1,3,5-Trichloro-2-methoxybenzene
Other names
2,4,6-Trichloroanisole
TCA
2,4,6-Trichloromethoxybenzene
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.001.585 Edit this at Wikidata
EC Number
  • 201-743-5
KEGG
RTECS number
  • MFCD00000588
UNII
  • InChI=1S/C7H5Cl3O/c1-11-7-5(9)2-4(8)3-6(7)10/h2-3H,1H3 checkY
    Key: WCVOGSZTONGSQY-UHFFFAOYSA-N checkY
  • InChI=1/C7H5Cl3O/c1-11-7-5(9)2-4(8)3-6(7)10/h2-3H,1H3
    Key: WCVOGSZTONGSQY-UHFFFAOYAT
  • COc1c(Cl)cc(Cl)cc1Cl
  • Clc1cc(Cl)cc(Cl)c1OC
Properties
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:
GHS07: Exclamation mark
Warning
H302, H319, H413
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 checkY☒N ?)

Occurrence

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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

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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

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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

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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

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  • 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

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References

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  1. ^ a b c Takeuchi, Hiroko; Kato, Hiroyuki & Kurahashi, Takashi (2013-09-16). "2,4,6-Trichloroanisole is a Potent Suppressor of Olfactory Signal Transduction". Proceedings of the National Academy of Sciences. 110 (40): 16235–16240. Bibcode:2013PNAS..11016235T. doi:10.1073/pnas.1300764110. ISSN 1091-6490. PMC 3791788. PMID 24043819.{{cite journal}}: CS1 maint: multiple names: authors list (link)[non-primary source needed]
  2. ^ a b Jackson, Ron S. (2009). "Chapter 3: Olfactory Sensations". Wine tasting: a professional handbook. Food science and technology international series (2nd ed.). Academic Press. ISBN 978-0-12-374181-3.
  3. ^ Young, W.F.; Horth, H.; Crane, R.; Ogden, T.; Arnott, M. (1996). "Taste and odour threshold concentrations of potential potable water contaminants". Water Research. 30 (2): 331–340. Bibcode:1996WatRe..30..331Y. doi:10.1016/0043-1354(95)00173-5.
  4. ^ Hovander, t. Malmberg, m. Athanasia, L.; Malmberg, T.; Athanasiadou, M.; Athanassiadis, I.; Rahm, S.; Bergman, A.; Wehler, E. K. (2002). "Identification of Hydroxylated PCB Metabolites and Other Phenolic Halogenated Pollutants in Human Blood Plasma". Archives of Environmental Contamination and Toxicology. 42 (1): 105–117. Bibcode:2002ArECT..42..105H. doi:10.1007/s002440010298. PMID 11706375.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  5. ^ 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.
  6. ^ These include Central and South America.[citation needed]
  7. ^ a b Spadone, Jean Claude; Takeoka, Gary & Liardon, Remy (1990). "Analytical Investigation of Rio Off-Flavor in Green Coffee". Journal of Agricultural and Food Chemistry. 38: 226–233. doi:10.1021/jf00091a050.{{cite journal}}: CS1 maint: multiple names: authors list (link) Note, at best, this source states that 2,4,6-trichlorophenol is "the probable precursor of TCA".
  8. ^ Pereira, Helena (2007-01-01), Pereira, Helena (ed.), "Chapter 14 - Wine and cork", Cork, Amsterdam: Elsevier Science B.V., pp. 305–327, ISBN 978-0-444-52967-1, retrieved 2024-01-14
  9. ^ a b Cravero, Maria Carla; Bonello, Federica; Pazo Alvarez, Maria del Carmen; Tsolakis, Christos; Borsa, Daniela (24 June 2015). "The sensory evaluation of 2,4,6-trichloroanisole in wines: The sensory evaluation of 2,4,6-trichloroanisole in wines". Journal of the Institute of Brewing. 121 (3): 411–417. doi:10.1002/jib.230.
  10. ^ Crane, Louise (22 March 2019). "Trichloroanisole: Cork taint". Chemistry World. Retrieved 2024-01-14.
  11. ^ With regard to circumstantial evidence, Spodone, et al., op. cit., note that Rio off-flavor is associated with "beans heavily infested with various fungi (Aspergilli, Fusaria, Penicillia, Rhizopus, etc.) and bacteria (Lactobacilli, Streptrococci)".
  12. ^ NTP (National Toxicology Program). 2021. "2,4,6-Trichlorophenol", Report on Carcinogens, Fifteenth Edition. Research Triangle Park, NC: U.S. Department of Health and Human Services, Public Health Service. https://ntp.niehs.nih.gov/go/roc15 DOI: https://doi.org/10.22427/NTP-OTHER-1003
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