Syringol is the
organic compound
Some chemical authorities define an organic compound as a chemical compound that contains a carbon–hydrogen or carbon–carbon bond; others consider an organic compound to be any chemical compound that contains carbon. For example, carbon-co ...
with the formula HO(CH
3O)
2C
6H
3. The molecule is a
phenol, with
methoxy groups in the flanking (2 and 6) positions. It is the symmetrically
dimethylated derivative of
pyrogallol. It is a colorless solid, although typical samples are brown owing to air-oxidized impurities. Together with
guaiacol, syringol and its derivatives are produced by the
pyrolysis of
lignin. Specifically, syringol is derived from the
thermal decomposition of the
sinapyl alcohol component. As such, syringol is an important component of
wood smoke.
Syringyl/guaiacyl ratio
Lignin, comprising a major fraction of biomass, is sometimes classified according to the syringyl component. Pyrolysis of lignin derived from sinapyl alcohol affords syringol. The conversion involves replacement of the propenyl alcohol substituent of the sinapyl alcohol by hydrogen. A high syringyl (or S) content is indicative of lignin from
angiosperm
Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed within a fruit ...
s. In contrast, pyrolysis of lignin from
gymnosperms gives more
guaiacol, resulting from conversion of
coniferyl alcohol. These lignins have a high guaiacyl (or G) content.
Food preparation
In preparation of food by
smoking, syringol is the main chemical responsible for the smoky
aroma, while guaiacol contributes mainly to
taste. Artificial liquid or solid smoke flavorings also contain these chemicals, on average composing 13.73% and 13.42% of those products by mass respectively.
Chemical feedstock
Pyrolysis oil, a
biofuel
Biofuel is a fuel that is produced over a short time span from Biomass (energy), biomass, rather than by the very slow natural processes involved in the formation of fossil fuels such as oil. Biofuel can be produced from plants or from agricu ...
derived from woody biomass, can be optimized to yield syringol as a byproduct, potentially competing with petroleum-derived
phenols. Some studies indicate that syringol can substitute for
phenol formaldehyde resin, a commonly used, water resistant
adhesive for
plywood.
See also
*
Phenolic content in wine
*
Syringaldehyde
*
Syringic acid
*
Acetosyringone
*
Sinapaldehyde
*
Sinapinic acid
*
Sinapine
*
Canolol
References
{{reflist
O-methylated natural phenols