Journal of the American Chemical Society, Vol.138, No.46, 15110-15113, 2016
Paired Electrolysis in the Simultaneous Production of Synthetic Intermediates and Substrates
In electrochemical processes, an oxidation half-reaction is always paired with a reduction half reaction. Although systems for reactions such as the reduction of CO2 can be coupled to water oxidation to produce O-2 at the anode, large-scale O-2 production is of limited value. One may replace a low-value half-reaction with a compatible half-reaction that can produce a valuable chemical compound and operate at a lower potential. In doing so, both the anodic and cathodic half-reactions yield desirable products with a decreased energy demand. Here we demonstrate a paired electrolysis in the case of the oxidative condensation of syringaldehyde and o-phenyl-enediamine to give 2-(3,5-dimethoxy-4-hydroxypheny1)benzimidazole coupled with the reduction of CO2 to CO mediated by molecular electrocatalysts. We also present general principles for evaluating current-voltage characteristics and power demands in paired electrolyzers.