The electrochemical behavior of selected polar aprotic systems

The present work involves a rigorous study of the cathodic reactions of selected polar aprotic solvents including tetrahydrofuran (THF), dimethyxyethane (DME), propylene carbonate (PC) and γ-butyrolactone (BL) on gold electrodes using tetrabutylammonium perchlorate (TBAP) as an electrolyte. Under these conditions, passivation does not occur, therefore a rigorous product analysis could be carried out. ¹H NMR, ¹³C NMR, FT-ir and GCMS in conjuctions with cyclic voltammetry and bulk electrolysis were used in order to study the reduction products and their mechanisms of formation. The reduction pattern of the ethereal systems involves mostly cation (TBA^*) reduction to tributylamine butene and butane, PC solutions are reduced mostly to propene and propylene dicarbonate di-anion CH₃CH(OCO₂^-)CH₂(OCO₂^-). BL is reduced to an anion of cyclic β-keto ester. The influence of water contamination was also rigorously studied and found to have a pronounced effect on these reactions. Mechanisms of electroreduction of the above systems are discussed.