Catalytic conversion of cellulose to sorbitol over Ru supported on biomass-derived carbon-based materials

The direct conversion of cellulose into sorbitol, one of the platform molecules of highest potential, by using a low-cost catalyst that yields higher productivity is a current challenge. Ruthenium/glucose-derived carbons with tailored textural and chemical properties were prepared by combining two different strategies: activation and addition of carbon nanotubes (CNT) to obtain a hybrid carbon material (AG-CNT). The appropriate combination of both strategies results in materials with high microporosity and low acidity that favors the dispersion of the metal and, hence, improves the yield of sorbitol. The total conversion of cellulose (100%) and the highest yield of sorbitol (64.1%) were achieved over a hybrid catalyst with high specific surface area of 1200 m(2) g(-1) (Ru/AG-CNT1200) within 3 h of reaction, at 205 degrees C and 50 bar of H-2. In addition, the catalyst was successfully recycled in four runs. These results are better than those reported over Ru/CNT (the highest yield reported to date over carbon supports) under the same reaction conditions, indicating that CNT can be successfully replaced by a low-cost support derived from biomass. As a result, not only the highest yield of sorbitol is obtained, but cellulose, one of the most important fractions of biomass, is valorized through two pathways: the cellulose itself as the main raw material of the reaction and its monomer, glucose, for the preparation of the catalyst.