Transfer Hydrogenation with Waste-Derived Aqueous Solutions of Formic Acid Catalysed by the SulfoShvo Catalyst.

The OxFA process provides aqueous formic acid (FA) solutions of around 53 wt% directly from biomass-derived byproducts such as glycerol. The direct utilisation of this diluted FA stream in transfer hydrogenation reactions without neutralisation or buffering is demonstrated, enabled by the highly hydrophilic, acid-stable sulfoShvo catalyst operating at pH 1. Using levulinic acid (LA) as a model substrate, optimisation in pressure autoclaves identified 130 °C and catalyst loadings as low as 0.2 mol% as effective reaction conditions. Even under these harsh acidic conditions, the catalyst displays remarkable performance: at 100 °C, long-term stability is achieved with a turnover number (TON) of 3680, while operation at 130 °C allows efficient hydrogenation but reveals gradual deactivation at very low loadings (0.025 mol%). Beyond LA, a range of water-soluble carbonyl and olefinic substrates is successfully hydrogenated, highlighting the broad applicability of this sustainable approach. Overall, this study establishes the OxFA/sulfoShvo system as a robust and atom-economical strategy for the direct use of biomass-derived FA solutions in catalytic hydrogenation.