One-pot selective conversion of furfural into 1,5-pentanediol over a Pd-added Ir-ReO_x/SiO₂ bifunctional catalyst

One-pot selective conversion of furfural into 1,5-pentanediol (1,5-PeD) was carried out over Pd-added Ir-ReO_x/SiO₂ catalysts through two-step reaction temperatures. The Pd(0.66 wt%)-Ir-ReO_x/SiO ₂ catalyst showed the best performance in the production of 1,5-PeD from furfural. The maximum yield of 1,5-PeD was 71.4%. The furfural conversion and yield of 1,5-PeD was almost maintained during four repeated tests when the catalyst was calcined again. The characterization results from TPR, XRD, XANES, EXAFS and FT-IR of adsorbed CO indicated that Pd-Ir-ReO_x/SiO ₂ catalysts consisted of ReO_x-modified Pd metal particles and ReO_x-modified Ir metal particles. The lower-temperature reaction step was very crucial for the total hydrogenation of furfural into a tetrahydrofurfuryl alcohol intermediate, which was converted into 1,5-PeD by hydrogenolysis during the high temperature step over the ReO_x- modified Ir metal particles.