Chemistry and Chemical Biology ETDs

Publication Date

10-13-1974

Abstract

The mechanisms of the reduction of benzaldehyde and several sub­stituted benzaldehydes in the dipolar, aprotic solvent sulfolane, have been investigated. A combination of cyclic voltammetry, transmission spectroelectrochemistry and ring-disk voltammetry was used in this study.

Cyclic voltammetric studies indicated that the one-electron benz­aldehyde reduction was followed by a dimerization of the radical anion intermediate to the pinacol. The reduction peak potentials of the benzaldehydes were cathodically shifted in sulfolane compared to values obtained in aqueos media. This indicates an increase in the benzaldehyde reduction energy in the aprotic solvent. The rate of tl1c following chemical reaction was also slower than previously reported aqueous values (e.g. k2 (bcnzaldehydc) = 2. 4 x 10^3 l /m• sec). Plots of reduction potential versus Hammett parameter of the inductive substituent had a larger slope than previously reported. This indicates an enhanced sensi­tivity of the reduction to para-substituent.

Transmission spectroclectrochcmical studies of the reduction inter- mediates of several of these compounds were undertaken. The p-nitro­benzaldehyde two-electron reduction mechanism was elucidated by this technique. The first electron addition produces the radical anion species which is observed to complex with the unreduced parent molecule. The second electron addition produces the dianion species which disproportionates with the parent molecule.

Language

English

Document Type

Dissertation

Degree Name

Chemistry

Level of Degree

Doctoral

Department Name

Department of Chemistry and Chemical Biology

First Committee Member (Chair)

Nicholas Ernest Vanderborgh

Second Committee Member

Illegible

Third Committee Member

David Lee Vander Jagt

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