Pd Nanoparticles Supported on Activated Carbon and Their Application in the Oxidative Condensation Reaction of Furfural: Effect of Base and Oxidizing Agent on Catalytic Behavior and Deactivation

Abstract

Catalysts with different Pd loading (0.5–2 wt.%) supported onan activated carbon were synthesized and tested in the oxida-tive condensation reaction of furfural using absolute ethanol,sodium carbonate as base, and hydrogen peroxide as oxidiz-ing agent. The characterization of the catalysts reveals a highdispersion of the Pd-species in the form of Pd 0 . The catalyticresults reported that furan-2-acrolein is the main product witha maximum yield of 52% after 6 h of reaction at 130 °C for thecatalyst with the highest Pd content. To obtain this product, it isnecessary to have the presence of an oxidant as hydrogen per-oxide, to promote the oxidation of ethanol to acetaldehyde, andthen a base, which promotes its condensation reaction with thefurfural molecule. The progressive decay of the furan-2-acroleinyield and the conversion values after several cycles suggeststhe formation of carbonaceous deposits on the surface of thecatalysts, which block the metallic sites involved in the reac-tions, as was observed by X-ray photoelectron spectroscopy andCO-chemisorption studies.