2,4,6-trichloro anisole
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| Surname | 2,4,6-trichloro anisole | ||||||||||||||||||
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| Molecular formula | C 7 H 5 Cl 3 O | ||||||||||||||||||
| Brief description |
whitish powder |
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| Molar mass | 211.47 g mol −1 | ||||||||||||||||||
| Physical state |
firmly |
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| Melting point |
60-62 ° C |
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| boiling point |
132 ° C (37 hPa ) |
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| As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . | |||||||||||||||||||
2,4,6-Trichloroanisole ( TCA ) is a chlorine-containing , aromatic hydrocarbon with an intensely moldy, musty odor. This derivative of phenol is used as a fungicide used and is the main cause of Korkgeschmackes , the most important olfactory - gustatory wine fault and the muffle odor of building molds and older prefabricated houses made of wood.
Occurrence
2,4,6-Trichloroanisole is the main cause of a cork tone in wine . TCA gets into the wine through contaminated corks, among other things. Further sources of TCA and other substances responsible for the taste of the cork can be reaction products of pentachlorophenol (PCA), which comes from wood treated with PCA in the storage rooms, and other chlorinated and brominated substances or their reaction products such as cleaning agents containing chlorine. It can also be found in raisins, essential oils, drinking water, bottled mineral water, and beer. TCA has also been identified as an air pollutant in the indoor air of prefabricated houses.
If paper becomes moldy, 2,4,6-trichloroanisole is also formed.
Extraction and presentation
In the laboratory, 2,4,6-trichloroanisole is through methylation of 2,4,6-trichlorophenol accessible.
properties
The substance forms colorless crystal needles and is very sparingly soluble in water. 2,4,6-Trichloroanisole can be determined in terms of taste even in the lowest concentrations, the perceptibility (sensory limit) varies between about 5 and 15 ng / l. The odor threshold in the room air is given as 2 ng · m −3 . TCA breaks down at approx. 50 ° C. This is the reason why wine with cork clay can be used for cooking without any loss of quality.
Analytics
Solid phase micro-extraction with downstream GC / MS coupling is used for reliable identification and quantification of 2,4,6-trichloroanisole . The detection limit for examined water samples is given as 0.02 ng / l when using this method.
remedy
In older prefabricated houses, the typical "muffle smell" is caused by the biogenic breakdown of the wood preservative previously used, pentachlorophenol, to 2,4,6-trichloroanisole. Chlorine anisoles occurring in the room air can be removed (in addition to barrier coatings) by applying activated carbon wallpaper.
See also
Web links
- Entry to 2,4,6-trichloroanisole . In: P. J. Linstrom, W. G. Mallard (Eds.): NIST Chemistry WebBook, NIST Standard Reference Database Number 69 . National Institute of Standards and Technology , Gaithersburg MD
- AGÖF: chlorine anisoles
- Wine with cork clay belongs in the sauce , article in the Neue Zürcher Zeitung (NZZ).
Individual evidence
- ↑ a b c d e data sheet 2,4,6-trichloroanisole from Sigma-Aldrich , accessed on March 17, 2011 ( PDF ).
- ↑ a b Jan Gunschera: Development of a renovation process for odor- polluted older wooden houses by means of structural and chemical-physical measures ; Fraunhofer Institute for Wood Research, Braunschweig, 2019.
- ↑ Marc Platthaus Korkgeschmack viewed analytically, magazine 'Laborpraxis' from January 20, 2011, accessed on January 5, 2018.
- ↑ HR Buser, C. Zanier, H. Tanner: Identification of 2,4,6-Trichloroanisole as a Potent Compound Causing Cork Taint in Wine. In: Journal of Agricultural and Food Chemistry . 30 (2), 1982, pp. 359-362; doi: 10.1021 / jf00110a037 .
- ^ J. Stoffelsma, DB de Roos: Identification of 2,4,6-Trichloroanisole in Several Essential Oils. In: Journal of Agricultural and Food Chemistry . 21 (4), 1973, pp. 738-739; doi: 10.1021 / jf60188a035 . PMID 4718945 .
- ↑ S. Karlsson, S. Kaugare, A. Grimvall, H. Borén, R. Sävenhed: Formation of 2,4,6-trichlorophenol and 2,4,6-trichloroanisole during treatment and distribution of drinking water. In: Water Science and Technology . 31 (11), 1995, pp. 99-103; doi: 10.1016 / 0273-1223 (95) 00462-V .
- ^ C. Fischer, F. Fischer: Analysis of cork taint in wine and cork material at olfactory subthreshold levels by solid phase microextraction. In: Journal of Agricultural and Food Chemistry . 45 (6), 1997, pp. 1995-1997; doi: 10.1021 / jf970121r .
- ↑ Herbert Obenland, ifau Institute for Applied Environmental Research: chloroanisoles .
- ↑ Wolfgang Legrum: Fragrances, between stench and fragrance. Vieweg + Teubner Verlag, 2011, ISBN 978-3-8348-1245-2 , p. 43.
- ^ Decay of TCA
- ↑ A. Martínez-Uruñuela, JM González-Saiz C. Pizarro: multiple solid-phase microextraction in a non-equilibrium situation. Application in quantitative analysis of chlorophenols and chloroanisoles related to cork taint in wine. In: Journal of Chromatography A . 1089 (1-2), 2005, pp. 31-38. PMID 16130768 .
- ^ S. Machado, C. Gonçalves, E. Cunha, A. Guimarães, MF Alpendurada: New developments in the analysis of fragrances and earthy-musty compounds in water by solid-phase microextraction (metal alloy fiber) coupled with gas chromatography- ( tandem) mass spectrometry. In: Talanta . 84 (4), 2011, pp. 1133-1340. PMID 21530789 .