4-Ethylguaiacol

4-Ethylguaiacol, often abbreviated to 4-EG, is a phenolic compound with the molecular formula C₉H₁₂O₂. It can be produced in wine and beer by Brettanomyces.^[3] It is also frequently present in bio-oil produced by pyrolysis of lignocellulosic biomass.^[4]

4-Ethylguaiacol

Names
Preferred IUPAC name 4-Ethyl-2-methoxyphenol
Other names p-Ethylguaiacol Homocresol Guaiacyl ethane 2-Methoxy-4-ethylphenol
Identifiers
CAS Number	2785-89-9 Y
3D model (JSmol)	Interactive image
ChemSpider	56245 Y
ECHA InfoCard	100.018.637
PubChem CID	62465
UNII	C9NFD83BJ5 Y
CompTox Dashboard (EPA)	DTXSID0047038
InChI InChI=1S/C9H12O2/c1-3-7-4-5-8(10)9(6-7)11-2/h4-6,10H,3H2,1-2H3 Y Key: CHWNEIVBYREQRF-UHFFFAOYSA-N Y InChI=1/C9H12O2/c1-3-7-4-5-8(10)9(6-7)11-2/h4-6,10H,3H2,1-2H3 Key: CHWNEIVBYREQRF-UHFFFAOYAE
SMILES Oc1ccc(cc1OC)CC
Properties
Chemical formula	C9H12O2
Molar mass	152.193 g·mol−1
Appearance	Colorless liquid
Density	1064 kg/m3 (20 °C)[1]
Melting point	15 °C (59 °F; 288 K)
Boiling point	235.1 °C (455.2 °F; 508.2 K)[1]
Hazards
GHS labelling:[2]
Pictograms
Signal word	Warning
Hazard statements	H315, H319, H335
Precautionary statements	P302+P352, P305+P351+P338
NFPA 704 (fire diamond)	2 1 0
Safety data sheet (SDS)	External MSDS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is YN ?) Infobox references

Winemaking

It is produced along with 4-ethylphenol (4-EP) in wine and beer by the spoilage yeast Brettanomyces.^[3] When it is produced by the yeast to concentrations greater than the sensory threshold of >600 μg/L, it can contribute bacon, spice, clove, or smoky aromas to the wine. On their own these characters can be quite attractive in a wine, however as the compound usually occurs with 4-EP whose aromas can be more aggressive, the presence of the compound often signifies a wine fault. The ratio in which 4-EP and 4-EG are present can greatly affect the organoleptic properties of the wine.

Bio-oil

4-Ethylguaiacol can also be produced by pyrolysis of lignocellulosic biomass. It is produced from the lignin, along with many of the other phenolic compounds present in bio-oil. In particular, 4-ethylguaiacol is derived from guaiacyl in the lignin.^[4]

See also

• Yeast in winemaking
• Wine chemistry

References

1. Mozaffari, Parsa; Järvik, Oliver; Baird, Zachariah Steven (2020-10-28). "Vapor Pressures of Phenolic Compounds Found in Pyrolysis Oil". Journal of Chemical & Engineering Data. 65 (11): 5559–5566. doi:10.1021/acs.jced.0c00675. ISSN 0021-9568. S2CID 228958726.
2. GHS: Sigma-Aldrich W243604
3. Caboni, Pierluigi; Sarais, Giorgia; Cabras, Marco; Angioni, Alberto (2007). "Determination of 4-Ethylphenol and 4-Ethylguaiacol in Wines by LC-MS-MS and HPLC-DAD-Fluorescence". Journal of Agricultural and Food Chemistry. 55 (18): 7288–93. doi:10.1021/jf071156m. PMID 17676867.
4. Lyu, Gaojin; Wu, Shubin; Zhang, Hongdan (2015). "Estimation and Comparison of Bio-Oil Components from Different Pyrolysis Conditions". Frontiers in Energy Research. 3. doi:10.3389/fenrg.2015.00028. ISSN 2296-598X.