Novel Sn‐Nb‐Based Catalysts with Enhanced Acidity and Water Resistance for the Aqueous‐Phase Condensation of Light Oxygenated Compounds

Abstract Upgrading of light oxygenated compounds present in aqueous effluents obtained from primary treatments of biomass (pyrolysis, fermentation) is imperative in the current bio‐refinery business model development. In this work, efficient and water‐resistant catalysts are needed for the valorization of these residual streams via aqueous‐phase condensation reactions. Based on our previous results, where Nb‐based materials stand as promissory catalysts, the activity of tin‐niobium mixed oxides in the condensation of light oxygenates is here studied using a representative aqueous model mixture including acetic acid, propanal, acetol, and ethanol. Sn‐Nb mixed oxides preparation via co‐precipitation allow obtaining homogenous rutile‐phase materials with enhanced textural and acid properties compared to commercial catalysts or Sn‐Nb materials synthesized by different procedures. This work displays the potential of Sn‐Nb rutile‐phase catalysts with inherent hydrophobic characteristics for the conversion of light oxygenated compounds present in bio‐derived aqueous effluents into hydrocarbons and aromatics useful for liquid fuel applications. These pseudo‐crystalline Sn‐Nb materials show remarkable condensation activity by exposing Lewis acid sites capable of activating carbonyl compounds even in the presence of large amounts of water and organic acids. Therefore, these novel acid catalysts exhibit outstanding performance and stability in complex acidic aqueous environment compared to other Sn‐Ti and Ce‐Zr mixes oxides broadly used in these processes.