Direct Catalytic Conversion of Ethanol to C₅₊ Ketones: Role of Pd–Zn Alloy on Catalytic Activity and Stability

Abstract

Ethanol can be used as a platform molecule for synthesizing valuable chemicals and fuel precursors. Direct synthesis of C5+ ketones, building blocks for lubricants and hydrocarbon fuels, from ethanol was achieved over a stable Pd‐promoted ZnO‐ZrO2 catalyst. The sequence of reaction steps involved in the C5+ ketone formation from ethanol was determined. The key reaction steps were found to be the in situ generation of the acetone intermediate and the cross‐aldol condensation between the reaction intermediates acetaldehyde and acetone. The formation of a Pd–Zn alloy in situ was identified to be the critical factor in maintaining high yield to the C5+ ketones and the stability of the catalyst. A yield of >70 % to C5+ ketones was achieved over a 0.1 % Pd‐ZnO‐ZrO2 mixed oxide catalyst, and the catalyst was demonstrated to be stable beyond 2000 hours on stream without any catalyst deactivation.

Optimization of the Pd-Catalyzed Alkylation of the Fermentation-Derived Oxygenates Acetone and Butanol toward Sustainable Aviation Fuel (SAF) Intermediates

“…14,15 Most recent research on Pd catalysts has focused on synthesizing novel supports, most notably hydrotalcite, 17,18,20−22 and on the addition of promoter metals such as Cu, 20 Zn, or Zr. 19 However, while the outcomes of the resulting catalyst systems in terms of substrate conversion are comparable, the best results in terms of selectivity for jet-fuel ranged carbon chains are generally obtained with the benchmark Pd/C catalyst. 8,14,15 Previous studies on the Pd-catalyzed alkylation of C2−C4 compounds have predominately examined the influence of certain process variables (e.g., temperature, catalyst loading, and water content in the reaction media, among others) on the overall efficiency.…”

Oxygenate Reactions over PdCu and PdAg Catalysts: Distinguishing Electronic and Geometric Effects on Reactivity and Selectivity

“…Currently, many bimetallic catalytic systems are investigated in the context of biomass upgrading [15,16], given their unique catalytic properties that differ from those of their parents, often in nonlinear fashion [17]. Our own previous investigations also showed monometallic Pd/SiO2 to be an effective catalyst for octanol Guerbet condensation but at the expense of selectivity.…”