Electrolytic Reductive Coupling

The electrolysis of concentrated solutions of acrylonitrile in aqueous tetraethylammonium p‐toluenesulfonate at lead or mercury cathodes and at controlled pH yields adiponitrile in virtually quantitative yields and at current efficiencies close to 100%. If the catholyte has acrylonitrile concentrations much below 10% or contains alkali metal cations, increasing quantities of propionitrile appear as by‐product. An explanation is offered for this shift in product distribution. Variations in laboratory cell design and supporting electrolyte composition are discussed.