Total Hydrogenation of Furfural and 5-Hydroxymethylfurfural over Supported Pd–Ir Alloy Catalyst

Abstract

Hydrogenation of aqueous furfural was conducted with SiO 2 -suported palladium-based bimetallic catalysts. The combination of palladium and iridium gave the best performance for the total hydrogenation to tetrahydrofurfuryl alcohol. Higher H 2 pressure and lower reaction temperature were advantageous to suppress side reactions. The synergy between Pd and Ir in the hydrogenation catalysis is most remarkable for substituted furans as substrates. Furfural was first converted into furfuryl alcohol, which was further converted to tetrahydrofurfuryl alcohol. A small amount of tetrahydrofurfural was formed in the first step (∼20% selectivity), and the subsequent hydrogenation of tetrahydrofurfural was much slower. The combined yield of tetrahydrofurfuryl alcohol and tetrahydrofurfural reached 98%. The yield of tetrahydrofurfuryl alcohol reached 94% with larger amount of catalyst. Total hydrogenation of 5-hydroxymethylfurfural was also possible using Pd−Ir/SiO 2 catalyst. The performance of Pd−Ir/SiO 2 catalyst was slightly changed by repeated uses, and the used catalyst can be regenerated by calcination and reduction at 573 K. Characterization results showed that Pd−Ir alloy particles with size of ≤4 nm were formed on the catalyst. Addition of Ir much increased the TOF values as compared with Pd/SiO 2 with similar particle size, especially for CO hydrogenation. One factor of higher activity of Pd−Ir/SiO 2 than Pd/SiO 2 can be the change of adsorption mode: Ir atom on the surface promotes the adsorption at CO site, whereas the Pd surface strongly interacts with furan ring.

Hydrogenation of bio-oil into higher alcohols over Ru/Fe3O4-SiO2 catalysts

“…Reference source not found.. The range of reaction products observed in the present work agrees well with earlier studies where furfural and phenol hydrogenations were performed separately [19,22,[56][57][58][59][60]62,67].…”

“…The initial hydrogenation step over noble metal catalysts is an aldehyde reduction followed by the reduction of the furan ring [22,24,25,56,57] as presented in Figure 1. Moreover, furfuryl alcohol can be hydrogenated into cyclopentanone almost quantitatively over Ru catalysts supported on acidic metal-organic frameworks [58].…”

“…Its hydrogenation was extensively studied in literature. Nakagawa et al [22] demonstrated that introduction of Ir into Pd nanoparticles increases TOF due to increased adsorption of C=O bond. Pang et al [23,24] showed an increased aldehyde hydrogenation and hydrodeoxygenation selectivity with the introduction of thiols over Cu-based catalysts.…”

Supported Metal Catalysts for Total Hydrogenation of Furfural and 5-Hydroxymethylfurfural

“…In order to overcome the leaching and life problems, we explored the combination of Pd and another noble metal for the catalytic hydrogenation of furfural 57) . The catalysts were simply prepared by co-impregnation and reduction with H2 at 573 K. The reaction results are summarized in Table 2.…”

Ir-Pd nanoalloys with enhanced surface-microstructure-sensitive catalytic activity for oxygen evolution reaction in acidic and alkaline media

“…Actually, as an ordinary noble metal alloy, Ir-Pd nanocatalysts have been widely used in plenty of heterogeneous catalytic reactions, e.g. selective hydrogenation [22,23], hydrazine decomposition [24,25] and electrocatalysis [26][27][28][29]. However, to the best of our knowledge, in-depth research of Ir-Pd nanocatalysts for OER with surface-sensitive catalytic properties is seldom to be studied.…”