Supported metal catalysts for total hydrogenation of furfural and 5-hydroxymethylfurfural

Total hydrogenation of furfural and 5-hydroxymethylfurfural (HMF), both of which are important platform chemicals from biomass, produces tetrahydrofurfuryl alcohol (THFA) and 2,5-bis(hydroxymethyl)tetrahydrofuran (BHTHF), respectively, and these products can be used as solvent or raw material of resin. Ni catalysts can give good yields in these reactions; however the low activity and stability are problems. Supported monometallic Pd and Ru catalysts have been reported to be also active in hydrogenation, although the selectivity for total hydrogenation tends to be lower. Other monometallic catalysts such as Cu and Pt generally have low activity in furan ring hydrogenation of furfuryl alcohol (FOL) and 2,5-bis(hydroxymethyl)furan intermediates. We explored various multicomponent catalysts and found that Ni-Pd/SiO₂, Pd-Ir/SiO₂ and Rh-Ir-ReO_x/SiO₂ give good yield of THFA or BHTHF with much higher activity than the mixture of each component supported on SiO₂.