“Acidic-environment feature: /
Oft-stable reactant’s chem-cleaver. /
The process provides /
Alcohol and halide: /
Two products formed out of the ether.”
The 29 April 2025 Bluesky limerick addressed another common organic chemistry mechanism.
“Acidic-environment feature: /
Oft-stable reactant’s chem-cleaver…”
I’ve addressed the idea of a “functional group” before in this space. The term refers to a characteristic pattern (group) of atoms that shows up across a large number of molecules and governs, in part, how such molecules can react (function).
One functional group is the ether: an oxygen atom singly bonded to two alkyl (hydrocarbon) groups, abbreviated as R-O-R’, where R and R’ generically represent the alkyl substituents. An ether does not have the panoply of subsequent reactions available to it that many other functional groups do (comparatively, it’s an “oft-stable reactant”), but a few steps are feasible.
One pathway available is called acidic cleavage: the ether breaks apart in acidic conditions.
“The process provides /
Alcohol and halide…”
Lines three and four of the limerick are not comprehensive: the fate of an ether in acidic conditions would depend on whether the alkyl groups surrounding the oxygen are more amenable to substitution or elimination reactions.
However, in one simple case, an ether (R-O-R’) could react with acid to form an alkyl halide (RX) and an alcohol (R’-OH): as shown here:
R-O-R’ + HX → RX + HO-R’
[This would be an essential reversal of what is probably the most famous reaction involving ethers: the Williamson ether synthesis, named for Alexander Williamson (1824-1904), who developed it in 1850. Here, an alcohol is deprotonated in basic conditions; the resulting alkoxide ion reacts with an alkyl halide to form an ether.]
“Two products formed out of the ether.”
The idea for this poem began with the idiom “out of the ether.” I was intrigued to see whether I could reach that phrase via a reasonable chemistry discussion, and this generally seemed to work.
Chemphasis 