Hydrogenation of Sugars to Sugar Alcohols in the Presence of a Recyclable Ru/Al<sub>2</sub>O<sub>3</sub> Catalyst Commercially Available
Isaline Bonnin, Raphaël Méreau, Thierry Tassaing, François Jérôme, Karine De Oliveira Vigier
Abstract
Hydrogenation of sugar monomers to sugars alcohols was performed in the presence of a commercial Ru/Al2O3 catalyst. It was shown that glucose (10 wt %) was selectively converted to sorbitol with a yield around 97% under optimized conditions (100 °C, 30 bar, 150 min of reaction and 5 wt % of catalyst). The reaction pathway was determined by the analysis of intermediate compounds. This catalyst was stable up to 10 reaction cycles due to alumina phases of the support and the Ru particle sizes. Moreover, it was shown that during the reaction the catalyst is reactivate under hydrogen explaining its stability, helping to maintain its activity by avoiding its poisoning. The Ru leaching was rather low and the particle sizes were still around 2 nm after several cycles showing that the catalyst morphology was similar to the fresh one. This catalyst was also active in the hydrogenation of sugars such as fructose, mannose, galactose, and xylose to sugar alcohols. This commercial catalyst is a stable catalyst that can be used in the hydrogenation of various sugars exhibiting an outstanding stability.