Hydrodeoxygenation of benzofuran over activated carbon supported Pt, Pd, and Pt-Pd catalysts

Activated carbon supported Pt, Pd, and Pt-Pd catalysts have been successfully prepared by incipient wet impregnation with a hydrochloric solution of PdCl2 and PtCl4. Hydrodeoxygenation of benzofuran was used as a probe reaction to investigate their catalytic properties. The activated carbon supported Pt-Pd catalyst was confirmed to form Pt-Pd alloy by X-ray diffraction. All the catalysts were active in the hydrodeoxygenation of benzofuran. Pd catalyst did not only give higher hydrogenation activity, but also showed faster deoxygenation rate than the Pt catalyst. The Pt-Pd catalyst with the mole ratio of Pd/Pt = 4 showed the highest catalytic activity among all of the catalysts. 2-Ethylcyclohexanone, which was not observed over the sulfide catalysts, was detected as a new oxygen-containing intermediate in the hydrodeoxygenation of benzofuran over the activated carbon supported Pt, Pd, and Pt-Pd catalysts. A ketone/enol isomerization reaction route is proposed to happen over the activated carbon supported noble metal Pt, Pd, and Pt-Pd catalysts.