Selective Electrochemical Oxidation of p-Xylylene Glycol Coupled with the Hydrogen Evolution Reaction via a Continuous Flow Strategy

Catalytic oxidation of alcohols to their correspondingaldehydesand ketones plays a fundamental role in many industries, but conventionalstrategies suffer from high costs, harsh reaction conditions, andlow energy efficiency. Here, we combine the p-xylyleneglycol oxidation with the hydrogen evolution reaction via an I-/I-3 (-) redox mediator inan electrochemical flow system where inexpensive graphite felt (GF)is utilized as electrodes. In comparison to traditional chemical oxidation,the electrochemical flow synthesis via the mediator I-/I-3 (-) could offer an outstanding p-hydroxymethyl benzaldehyde selectivity of 96.5% and aFaradaic efficiency of 84.8%. Besides, we realize the gram-scale synthesisof p-hydroxymethyl benzaldehyde at the current densityof 25 mA/cm(2) with low energy consumption because of theprepared catalytically efficient GF-Cu7S4 andGF-Pt electrodes. We explore different substrates and observe theflexible adaptability of our proposed flow synthesis strategy, demonstratingits potential for industrial applications. An electrochemical flow synthesis strategyis proposed hereinfor the gram-scale synthesis of p-hydroxymethyl benzaldehydewith low energy consumption.