Selective Anodic Oxidation of Solketal as Acetal‐Protected Glycerol over Nickel Boride in Alkaline Media to Glyceric Acid**
Steffen Cychy, Sebastian Lechler, Martin Muhler
Abstract
Abstract Alkaline anodic oxidation of glycerol suffers from facile C−C bond cleavage, especially when using non‐precious metal electrocatalysts, which limits the yield of more valuable C 3 oxygenates. Usually, a high C 3 selectivity is a tradeoff with conversion for most catalysts. Thus, we used solketal as the reactant, which is acetal‐protected glycerol with acetone. CV experiments showed that solketal is oxidized over nickel boride (Ni x B) at potentials where NiOOH is formed. Electrolysis over Ni x B in a thin‐film spectroelectrochemical flow cell at 1.58 V vs. RHE to avoid pronounced oxygen evolution showed a stable current density of ca. 6 mA cm −2 . Simultaneously recorded ATR‐FTIR spectra revealed solketal conversion to solketalate and formate. Indeed, 59 % conversion and 77 % selectivity to glyceric acid were determined by HPLC after acidic cleavage of the acetal, resulting in a yield of 45 %. Therefore, solketal is a promising reactant for the selective electrosynthesis of glyceric acid.