4-Ethylphenol

Ethylphenol (4-EP) is an organic compound with the formula C2H5C6H4OH. It is one of three isomeric ethylphenols. A white solid, it occurs as an impurity in xylenols and as such is used in the production of some commercial phenolic resins. It is also a precursor to 4-vinylphenol.[3]

4-Ethylphenol[1]
Names
Preferred IUPAC name
4-Ethylphenol[2]
Other names
p-Ethylphenol
1-Ethyl-4-hydroxybenzene
1-Hydroxy-4-ethylbenzene
4-Hydroxyphenylethane
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.004.181
EC Number
  • 204-598-6
KEGG
UNII
  • InChI=1S/C8H10O/c1-2-7-3-5-8(9)6-4-7/h3-6,9H,2H2,1H3 checkY
    Key: HXDOZKJGKXYMEW-UHFFFAOYSA-N checkY
  • InChI=1/C8H10O/c1-2-7-3-5-8(9)6-4-7/h3-6,9H,2H2,1H3
    Key: HXDOZKJGKXYMEW-UHFFFAOYAF
  • Oc1ccc(cc1)CC
Properties
C8H10O
Molar mass 122.167 g·mol−1
Appearance White solid
Odor leather-like
Melting point 45.1 °C (113.2 °F; 318.2 K)
Boiling point 218 °C (424 °F; 491 K)
Hazards
GHS labelling:
GHS05: Corrosive
Danger
H314
P260, P264, P280, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P310, P321, P363, P405, P501
NFPA 704 (fire diamond)
NFPA 704 four-colored diamond
2
1
0
Flash point 104 °C (219 °F; 377 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)
Infobox references

Natural occurrences

In wine and beer, 4-EP is produced by the yeast Brettanomyces. At concentrations greater than 140 μg/L (typical sensory threshold) it gives the wine aromas described as barnyard, medicinal, band-aids, and mousy. In certain Belgian beer styles, a high 4-EP level may be desirable; however, very high levels of the compound in wine can render it undrinkable. The level of 4-EP is roughly proportional to Brettanomyces concentration and activity, and can therefore be used as an indicator of the yeast's presence. There are significant differences between strains of Brettanomyces in their ability to produce 4-EP.

4-EP is also a component of castoreum, the exudate from the castor sacs of the mature North American beaver (Castor canadensis) and the Eurasian beaver (Castor fiber), used in perfumery.

Biochemistry

4-EP is biosynthesized in two steps from p-coumaric acid. Decarboxylation gives 4-vinylphenol as catalyzed by the enzyme cinnamate decarboxylase.[4] 4-Vinylphenol is further reduced to 4-ethylphenol by the enzyme vinyl phenol reductase. Coumaric acid is sometimes added to microbiological media, enabling the positive identification of Brettanomyces by smell.

The conversion of p-coumaric acid to 4-EP by Brettanomyces

See also

References
  1. "4-Ethylphenol MSDS". Archived from the original on 2002-11-08. Retrieved 2002-11-08.
  2. Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. p. 690. doi:10.1039/9781849733069-FP001. ISBN 978-0-85404-182-4. Only one name is retained, phenol, for C6H5-OH, both as a preferred name and for general nomenclature. The structure is substitutable at any position. Locants 2, 3, and 4 are recommended, not o, m, and p.
  3. Fiege, Helmut; Voges, Heinz-Werner; Hamamoto, Toshikazu; Umemura, Sumio; Iwata, Tadao; Miki, Hisaya; Fujita, Yasuhiro; Buysch, Hans-Josef; Garbe (2000). "Phenol Derivatives". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a19_313.
  4. Brettanomyces Monitoring by Analysis of 4-ethylphenol and 4-ethylguaiacol Archived 2008-02-19 at the Wayback Machine at etslabs.com
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