Flow Reactor Studies of the Paired Electro‐Oxidation and Electroreduction of Glucose

The electrochemical oxidation of glucose to gluconic acid and reduction of glucose to sorbitol have been paired in an undivided packed‐bed electrode flow reactor. A Raney Ni powder electrocatalyst significantly improved the current efficiency for sorbitol production, as compared to a high hydrogen overpotential cathode. The optimum operating conditions for the paired syntheses are activity W‐2 Raney Ni powder cathode, graphite chip anode, a 1.6M glucose and initial solution composition, pH 5–7, 60°C solution temperature, an applied current of 250–500 mA per 10g of nickel powder cathode and a solution volumetric flow rate of 100 ml‐min−1. Under these conditions, the sorbitol current efficiencies are 80–100%, the gluconic acid efficiencies are 100%, and the product yields are very high.