In this work, different approaches for the direct and indirect electrooxidation of glycerol, a by‐product of oleochemistry and biodiesel production, for the synthesis of value‐added products and of intermediates for biofuel/electrofuel production, were investigated and compared. For the direct electrooxidation, metallic catalysts were used, whose surfaces were modified by promoters or second catalysts. Bi‐modified Pt electrodes (PtxBiy/C) served as model systems for promoter‐supported electrocatalysis, whereas IrO2‐modified RuO2 electrodes were studied as catalyst combinations, which were compared under acidic conditions with the respective monometallic catalysts (Pt/C, RuO2/Ti, IrO2/Ti). Furthermore, inorganic halide mediators (chloride, bromide, iodide) and organic nitroxyl mediators (4‐oxo‐2,2,6,6‐tetramethyl‐piperidin‐1‐oxyl and 4‐acetamido‐2,2,6,6‐tetramethyl‐piperidin‐1‐oxyl) were evaluated for indirect electrooxidation. These different approaches were discussed regarding selectivity, conversion, and coulombic efficiency of the electrochemical glycerol oxidation.

Aiming toward a scalable continuous electrochemical production of valeric acid, the mutual insolubility of valeric acid with the aqueous reaction medium of levulinic acid and the aqueous electrolyte are investigated in order to assess the possibility for an integrated product separation based on the liquid-liquid equilibrium of the system. The influence of the electrolyte concentration in the mixture and the mixture temperature on the liquid-liquid equilibrium is studied. Based on these results, the possibility for a batch and a continuous product separation process is developed and discussed.