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

One-pot selective conversion of furfural into 1,5-pentanediol (1,5-PeD) was carried out over Pd-added Ir-ReOx/SiO2 catalysts through two-step reaction temperatures. The Pd(0.66 wt%)-Ir-ReOx/SiO2 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-ReOx/SiO2 catalysts consisted of ReOx-modified Pd metal particles and ReOx-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 ReOx-modified Ir metal particles.