Studies on the partial reduction of nitrobenzene, with particular reference to electrode geometry

Abstract

This thesis describes an investigatipn of an organic electrooynthesis conducted at controlled electrode potentials. The reaction examined was the electrolytic reduction of nitrobenzene. As a method of producing p-aminophenolp this process is potentially of commercial interest. A quantitative study of the process has demonstrated that both the rate and the course of the reaction are primarily dependent on the applied electrode potential. Further, the imposition of other advantageous variables modifies but does not alter this basic dependence. The results suggest that there are optimum values of eleotrode potential, specific to the operating conditions at which both the rate and efficiency of the preparation of P-aminophenol attain maxima. The lack of high capacity electrodes suitable for this reaction, and which are capable of operation within specific ranges of electrode potential, prompted the investigation of packed bed electrode arrangements. The most promising type of packing proved to be samples of knitted copper wire. These arrangements were found to effect the reaction efficiently giving very high electrode capacities. A better estimation of the variation of the electrode potential within such three-dimensional electrode forms has been achieved by mathematical analysis. By employing the data of the test reaction and imposing a limit to the variation of the electrode potential, calculations of the sizes of various bed electrode arrangements to effect this reaction have been made. The resultant correlations have produced some interesting parameters from which, it is proposed, future electrode arrangements for a variety of processes can be estimated.