Selective liquid phase hydrogenation of furfural to furfuryl alcohol by Ru/Zr-MOFs

Selective hydrogenation of furfural to furfuryl alcohol under mild conditions was evaluated over Ru nanoparticles supported on a series of zirconium based metal organic frameworks (UiO-66, UiO-67, Zr-6-NDC, MIL-140A, MIL-140B, and MIL-140C). The particle size and oxidation state of Ru in the catalysts was characterized by TEM, H-2-TPR, and XPS. The consecutive reduction by N2H4.H2O and hydrogen flow led to Ru metal nanoparticles, unless the interaction of the Ru precursor with the organic linkers was strong as found for the carboxylic acid groups in MIL-140C. Although the Ru nanoparticle surface was oxidized when exposed to air, the surface RuOx could be reduced under reaction conditions for Ru/Ui066, consistent with its high catalytic activity. This catalyst exhibited 94.9% yield of furfuryl alcohol and could be reused in five consecutive reaction cycles without appreciable loss in performance. (C) 2015 Elsevier B.V. All rights reserved.