Light-driven acetic acid coupling for the production of succinic acid

Treating and recycling high concentration acetic acid in the exhaust water has long posed a challenge in industry. These wastes containing acetic acid are typically processed via basic neutralization, characterized by high acidity and resistance to degradation, which can bring potential economic burden and environmental hazards. Here we report a new photocatalytic conversion route for addressing high concentrations of acetic acid. This process transforms acetic acid into valuable succinic acid through dehydrogenative coupling. Additionally, the photocatalytic conversion of acetic acid exhibits structure sensitivity when employing Pt cocatalysts of varying sizes. Through inhibiting the undesirable H termination of active free radicals over small Pt atoms and clusters, the rate of undesired decarboxylation reactions can be decreased by 75 %. This effectively enhances the selectivity of the coupling product succinic acid by 2.1 times, achieving a succinic acid formation rate of 7.28 mmol/(g cat •h). This work offers a theoretical guidance for searching value-added reaction pathways of acetic acid, thereby establishing an innovative approach for high concentration exhaust acetic acid treatment and converting low value monocarboxylic molecules into valuable diacid polymerization monomers under a mild and green condition.