Studies on the electrolytic reduction of organic compounds

After making a detailed literature survey of all nitro compounds studied by electrolytic method by various workers, industrial applications of the compounds studied, their demand in the country, other methods of manufacture etc., have been briefly summarised. Electrolytic reduction of nitrobenzene to aniline was studied on bench scale to optimise the conditions for maximum yield of aniline by adding various addition agents. Having observed that titanous titanic redox system works better than other addition agents, experiments were done to fix the parameters like current density, acid concentration, temperature, depolarizer ratio, etc. After optimizing the conditions reuse of electrolyte was studied for the reduction of nitrobenzene to aniline using Ti3+/Ti4+ redox system. Thus, it was shown that same electrolyte can be used ten times without any loss in yield, by adjustment of the concentration of free acid of the catholyte after each use. Scalling up was done on 150 A scale and 1000 A scale for the production of aniline on industrial scale and the results are shown with block type flow sheet diagram. Potential versus current density studies were made for the electrolytic reduction of nitrobenzene to aniline with and without titanic sulphate for stationary as well as rotating electrode to know the depolarization characteristics at different current densities ranging between those current densities which are normally applied for the industrial production of aniline. Similar to electrochemical reduction of nitrobenzene to aniline, electro reduction of ortho and para nitrophenols, m-dinitrobenzene, and 2,4 dinitrotoluene to their respective amino compounds, viz., ortho and para aminophenols, m-phenylenediamine and 2,4 diaminotoluene were studied using same redox system and conditions were optimized to obtain maximum yield of respective amine compounds. Similarly potential versus current density studies were made for each nitro compound as was done for nitrobenzene and the results are presented. Chemical kinetics for the reaction between titanous sulphate and nitrobenzene was studied to know the order of reaction at a condition similar to the condition of electrolytic reduction of nitrobenzene to aniline. Kinetic constants were obtained from the experimental results