Hydrodeoxygenation of Benzofuran over Silica-Alumina-Supported Pt, Pd, and Pt-Pd Catalysts

A series of monometallic Pt and Pd and alloyed Pt-Pd catalysts (mole ratio of Pt/Pd = 1, 4, and 0.25) were prepared with silica-alumina as support. CO chemisorption and X-ray diffraction (XRD) were applied to characterize the resulting samples. The performance of the catalysts for hydrodeoxygenation (HDO) for benzofuran (BF) was evaluated in a fixed-bed flow reactor at 280 degrees C and 3.0 MPa. Only one major route was found for the reaction network of HDO of BF among the catalysts. First, BF was transformed to 2,3-dihydrobenzofuran with the hydrogenation at the heterocyclic ring, followed by further conversion to octahydrobenzofuran at the benzene ring. The main hydrocarbon products are ethylcyclohexane and methylcyclohexane. The silica-alumina-supported catalysts also showed significant cracking activities, with the observation of the production of methylcyclohexane. The activity and product selectivity of Pt, Pd, and bimetallic Pt-Pd catalysts with the influence of the weight time were investigated in detail. Bimetallic Pt-Pd catalysts were higher in activity in the hydrogenation and the removal of oxygen from BF than their monometallic counterparts. The Pd4Pt1 catalyst presented the highest activity, with 99% conversion of BF and 100% selectivity toward 2,3-dihydrobenzofuran among all of the other catalysts at low weight time.