Zirconium phosphate combined with Ru/C as a highly efficient catalyst for the direct transformation of cellulose to C6 alditols
The selective transformation of cellulose to C6 alditols provides a feasible route towards the sustainable synthesis of chemicals and fuels. Herein, the catalytic performance of amorphous zirconium phosphate (ZPA) combined with 5 wt% Ru/C was evaluated in the direct conversion of cellulose to C6 alditols (sorbitol and mannitol) under hydrothermal conditions. The yield of C6 alditols reached 63.5% and 85.5% with microcrystalline cellulose and ball-milled cellulose as the feedstock, respectively. This hybrid catalyst was developed to convert concentrated cellulose to obtain C6 alditols with a high concentration of 68.8 mg mL−1 in the final products. The high yield of C6 alditols from cellulose was ascribed to the fact that ZPA favoured the adsorption of cellulose and promoted its depolymerization to cellobiose and glucose, which was hydrogenated immediately to C6 alditols over Ru/C. The weak adsorption of C6 alditols over ZPA inhibited the dehydration of C6 alditols to sorbitan. Furthermore, ZPA exhibited excellent hydrothermal stability and could be reused for several runs.