Cathodic Reduction Studies

Bergman, Imanuel (1954) Cathodic Reduction Studies. PhD thesis, University of Glasgow.

Abstract

The work on which this thesis is based has consisted, in the main, of the study of the reduction of aromatic organic compounds at mercury cathodes. The polarograph has been used to obtain energy quantities which have been related to the structure and electronic distribution of the molecules studied. The use of two non-aqueous solvents, glacial acetic acid and ethylene glycol mono-methyl ether, as polarographic solvents has been extended. The technique of reduction at controlled potential has been used to investigate reduction mechanisms, and for the preparation of air-sensitive material. The first part of the work consists of the investigation of the polarography of some nitro compounds in glacial acetic acid. This solvent is of interest because it provides an acidic medium in which a large number of organic compounds are soluble, and because of its comparatively high decomposition potential. A series of nitro compounds was studied because of the special interest of the reduction of the nitro group in a medium of constant acidity function. The influence of substituents on the ease of reduction is discussed and results shown to be in general agreement with accepted views on their polar effects. (A reprint of the paper in the Transactions of the Faraday Society describing this work is included in the Appendix.) The reduction states of some nitro compounds and related substances were studied by coulometric reduction at a controlled potential using a stirred mercury cathode. The results, given in Part 2, agree substantially with those obtained by polarography, both in aqueous media and in concentrated sulphuric acid, and glacial acetic acid. In order to clarify the part played by phenyl-hydroxyl-amine in the polarographic reduction of nitrobenzene, phenyl-hydroxylamine has been prepared by cathodic reduction. Solutions obtained in this way have been examined spectrophotometrically in order to measure the pK of phenyl-hydroxylamine and to study the acid catalysed re-arrangement to p-amino-phenol. (This work has been published in the Transations of the Faraday Society, and a reprint is included in the Appendix). The half-wave potentials of several series of polycyclic aromatic hydrocarbons have been measured in ethylene glycol mono-methyl ether. These potentials are shown in the third part to be directly related to the wave-numbers of the p-bands in the absorption spectra of the hydrocarbons. Thus energy quantities derived from two very different measurement techniques are shown to be similarly related to molecular electronic distribution.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Keywords: Organic chemistry
• Date of Award: 1954
• Depositing User: Enlighten Team
• Unique ID: glathesis:1954-79072
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 05 Mar 2020 11:44
• Last Modified: 05 Mar 2020 11:44
• URI: https://theses.gla.ac.uk/id/eprint/79072