When reading an infrared (IR) spectrum for an unknown compound, you check for certain functional groups in a certain order. If C=O is absent, you check for alcohols/phenols (-OH), then for amines (N-H), then for ethers (C-O, & the absence of -OH).
So, I was wondering: If you look at the structure of eugenol, there is a hydroxyl (-OH) group as well as an ether (R-O-R' = aromatic ring-O-CH3) group. If an ether only exists when -OH is absent, what do you call the R-O-R' group?
The R-O-R' group in eugenol is actually called an "aryl ether." It consists of an aromatic ring (R) connected to an oxygen atom (O) which is in turn connected to a methyl group (R'). The presence of the -OH group (hydroxyl) and the aryl ether group in eugenol is an exception to the order in which you would typically check for functional groups in an IR spectrum analysis.
In the usual order, one would first check for the presence of C=O (carbonyl) groups. If C=O is absent, then alcohols and phenols (-OH) would be checked next. Following that, amines (N-H) would be examined, and finally, ethers (C-O) would be considered. However, in the case of eugenol, both the -OH group and the aryl ether group are present.
This means that eugenol contains both an alcohol (hydroxyl) functional group and an ether group. The absence of the -OH group is not a requirement for the presence of an ether in general. In the case of eugenol, the aryl ether group coexists with the -OH group, which is a unique feature of this compound.