(629u) Effect of the Support of Metal Oxide Supported Ruthenium Catalysts for the Conversion of Cellulose Into Sugar Alcohols
The increase of the world’s energy needs with the combination of several factors including the diminishing of petroleum resources, the increase in the petroleum derivatives prices, as well as the increase of green house gas emissions, have caused great interest of finding new processes to produce renewable fuels, such as the hydrogenation of cellulose by a bifunctional catalyst into sugar alcohols. In this work, we focus on the study of the effect of the support acid-base properties on the catalytic performance during the conversion of cellulose into sugar alcohols, which can be used in a biorefinery platform as a renewable feedstock for the production of fuels and high value chemicals. The series of metal oxide supports studied includes MgO, ZrO2, TiO2, two types of Nb2O5, Al2O3, and SiO2. Furthermore, binary and ternary metal oxides were also analyzed such as two types of SiO2-TiO2, WO3-TiO2, Al2O3-TiO3, Fe2O3-TiO2 and SiO2-TiO2-WO3. The materials used display a wide range of acid-base properties. Ru was supported using evaporative deposition on all the supports. The catalytic activity appears to have a correlation with the Sanderson electronegativity for the single metal oxide materials passing through a maximum for Ru/Nb2O5 for the supported catalyst and through ZrO2 for the supports. The catalytic materials were characterized using nitrogen adsorption, X-Ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR). Ru/Nb2O5 has a significantly lower surface area than Ru/SBA-15 but displays higher activity. The selectivity of the mesoporous material is equally better than that of Ru/Nb2O5. On the other hand, the structural differences between SiO2 and SBA-15 results in a significant difference in selectivity, and smaller effect over the activity. The binary metal oxide TiO2-WO3 had a better activity and selectivity than SBA-15, probably due to its more acidic character. Ru/TiO2-WO3 displayed the best cellulose conversion; on the other hand Ru/SiO2-TiO2-WO3 shows better selectivity to sugar alcohols. Also it is seen that the identity of nonporous supports has small effect on cellulose hydrogenation activity.