Title:
A polarographic study of the reduction of unsymmetrical benzils.
A polarographic study of the reduction of unsymmetrical benzils.
Author(s)
Sobieski, James F.
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Abstract
This investigation applied the techniques of polarography and controlled
potential electrolytic reduction to the study of a series of unsymmetrical benzils.
Eleven unsymmetrical benzils were synthesized and studied in 50% ethanol-water
(by volume) solvent systems buffered at pH 1, 5, and 13. The results showed that,
with unsymmetrical benzils substituted with electron-withdrawing or electrondonating
groups, the carbonyl closest to the ring with the least electron-donating
power was the preferred reaction site. However, the dicarbonyl system was nevertheless
reduced as a unit, and Hammett sigma values of disubstituted symmetrical
benzils were approximately additive. This was ascertained by comparing the ease
of reduction of eight unsymmetrical benzils to the ease of reduction of the corresponding
disubstituted symmetrical benzils. It was proposed that the electrons
were added to the oxygen of one carbonyl, and that the second carbonyl was involved
in the reduction chiefly through complete polarization of the dicarbonyl system
at the electrode.
In general, the reduction of unsymmetrical benzils appeared to follow the
same path previously reported for symmetrical benzils.
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Date Issued
1967-01-01
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2615098 bytes
Resource Type
Text
Resource Subtype
Dissertation