Chronopotentiometry in Acetonitrile : Oxidation of Substituted Acetates and Substituted Ferrocenes at Platinum Electrodes

Author: Russell, Charles Dyer

Year: 1963

Degree: Dissertation (Ph.D.)

Advisor: Anson, Fred C.

Committee Member: Unknown, Unknown

Option: Chemistry

DOI: 10.7907/ZJJE-MQ70

Abstract

Chronopotentiometry was used to study electrode reactions in acetonitrile solutions Evidence is presented for the formation of an oxide film on platinum electrodes in acetonitrile by reaction with traces of moisture. Oxygen dissolved in acetonitrile solutions of tetraethylammonium perchlorate is reduced to peroxide at the platinum electrode, although it is not reduced in solutions of alkali perchlorates. The potential-limiting background reactions in tetraethylammonium perchlorate solutions were investigated by current-reverse chronopotentiometry.

Oxidation of acetate ion in acetonitrile gave 91 ± 6% current yield of carbon dioxide and 77 ± 3% ethane. Acetic acid does not react below the anodic background potential. Oxidation of substituted acetates was studied chronopotentiometrically but traces of moisture in the solution were found to react simultaneously at the electrode and seriously interfere. Water is not oxidized below the background potential in the absence of carboxylate ion.

Oxidation potentials for a series of substituted ferrocenes were measured chronopotentiometrically and evidence was found for a new type of neighboring group interaction between the iron in ferrocinium ion and oxygen, nitrogen, or halogen in the ring position. The same substitutuents did not interact in the alpha position.

A computer program was written for the calculation of kinetic data from totally irreversible chronopotentiometric waves and used to evaluate graphical methods previously proposed. New graphical and algebraic methods were also evaluated. These methods were applied to the determination of rate constants for the reduction of iodate ion at mercury in aqueous sodium hydroxide solution.

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