Acid-Functionalized Mesoporous Carbon: An Efficient Support for Ruthenium-Catalyzed γ-Valerolactone Production

• Published in: ChemSusChem 2015-08, Vol.8 (15), p.2520-2528
• Main Authors: Villa, Alberto, Schiavoni, Marco, Chan-Thaw, Carine E., Fulvio, Pasquale F., Mayes, Richard T., Dai, Sheng, More, Karren L., Veith, Gabriel M., Prati, Laura
• Format: Article
• Language: English
• Subjects: carbon; Carbon - chemistry; Catalysis; Hydrogenation; INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Lactones - chemical synthesis; Levulinic Acids - chemistry; mesoporous materials; Porosity; ruthenium; Ruthenium - chemistry; supported catalysts
• ISSN: 1864-5631; 1864-564X
• DOI: 10.1002/cssc.201500331

The hydrogenation of levulinic acid has been studied using Ru supported on ordered mesoporous carbons (OMCs) prepared by soft‐templating. P‐ and S‐containing acid groups were introduced by postsynthetic functionalization before the addition of 1 % Ru by incipient wetness impregnation. These functionalities and the reaction conditions mediate the activity and selectivity of the levulinic acid hydrogenation. The presence of S‐containing groups (Ru/OMC‐S and Ru/OMC‐P/S) deactivates the Ru catalysts strongly, whereas the presence of P‐containing groups (Ru/OMC‐P) enhances the activity compared to that of pristine Ru/OMC. Under mild conditions (70 °C and 7 bar H2) the catalyst shows high selectivity to γ‐valerolactone (GVL; >95 %) and high stability on recycling. However, under more severe conditions (200 °C and p H 2=40 bar) Ru/OMC‐P is particularly able to promote GVL ring‐opening and the consecutive hydrogenation to pentanoic acid. Which acid? Ordered mesoporous carbons are functionalized using P‐ and S‐containing acid groups before the addition of Ru. The presence of S groups deactivates the Ru catalysts strongly, whereas the presence of P groups enhances the activity of the catalyst in levulinic acid hydrogenation and its durability.