d-Glucose hydrogenation/hydrogenolysis reactions on noble metal (Ru, Pt)/activated carbon supported catalysts
•Glucose hydrogenation/hydrogenolysis at harsh conditions (180 °C, 3–12 h, 1.6 MPa H2).•Pt/AC is highly selective for glucose hydrogenation to sorbitol.•Single crystal Ru(0) nanoparticles (2–4 nm) favor sorbitol hydrogenolysis to arabinitol.•Ru content and reduction method (NaBH4 or H2) affect selectivity to C3–C6 sugar alcohols.
In the present work we studied the hydrogenation/hydrogenolysis of d-glucose over Pt and Ru catalysts supported on activated micro/mesoporous carbon (AC), under low hydrogen pressure (1.6 MPa) and relatively high reaction temperature, i.e. 180 °C. We also studied the effect of metal content (1–5 wt.%), method of metal pre-treatment/reduction (H2 at 350 °C or NaBH4) and reaction time (1–12 h). All the Ru and Pt/AC catalysts were very active (conversion ≥97%) with the Pt/AC catalysts being also very selective toward sorbitol (sel. ≥90%) irrespective of metal content, method of reduction and reaction time (up to 12 h). On the other hand, the Ru/AC catalysts exhibited a wide range of sorbitol selectivity values (55–93%) having various C3–C6 sugar alcohols (1,2,5,6-hexanetetrol, arabinitol, threitol, glycerol and 1,2-propanediol) as main by-products. The formation of by-products was dependent on the crystalline/amorphous nature of Ru and Ru(O)xδ+ nanoparticles which were in turn affected by the Ru content and the method of reduction.
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Journal: Catalysis Today - Volume 257, Part 2, 15 November 2015, Pages 281–290