Efficient solvent-free hydrogenation of ketones over flame-prepared bimetallic Pt-Pd/ZrO(2) catalysts

Abstract

Named and flamed: Bimetallic Pt-Pd/ZrO(2) catalysts with different Pt/Pd atomic ratios and high dispersion of the metal nanoparticles are prepared by a single-step flame-spray pyrolysis. The catalysts show excellent activity and tunable product selectivity for the solvent-free hydrogenation of the ketone model compounds cyclopentanone and acetophenone.

Fig. 1

STEM images of Pt/ZrO₂ (a), Pt₅₀Pd₅₀/ZrO₂ (c), and Pd/ZrO₂ (e). TEM images of Pt/ZrO₂ (b) and Pt₅₀Pd₅₀/ZrO₂ (d). EDX spectrum of Pt₅₀Pd₅₀/ZrO₂ (f).

Fig. 2

DRIFT spectra of CO adsorption on reduced Pt/ZrO₂ (a), Pt₇₅Pd₂₅/ZrO₂ (b), Pt₅₀Pd₅₀/ZrO₂ (c), Pt₂₅Pd₇₅/ZrO₂ (d), and Pd/ZrO₂ (e).

Fig. 3

Influence of Pd content of Pt-Pd/ZrO₂ catalysts on the conversion (open circles) and TOF (full circles) of cyclopentanone HDO. Conditions: 160°C, 60 bar hydrogen pressure, 3 h reaction time.

Fig. 4

Influence of the Pd content of Pt-Pd/ZrO₂ catalysts on the conversion (open circles) and TOF (full circles) of acetophenone. Conditions: 140°C, 60 bar hydrogen pressure, 3 h reaction time.

Fig. 5

Influence of Pd content of Pt-Pd/ZrO₂ catalysts on the selectivity to products at an acetophenone conversion of ca. 60%: Selectivity to C=O bond HDO affording EB (open squares); Selectivity to phenyl ring hydrogenation products affording CE+EC+CMK (full squares). Beside these products 1-phenylethanol (PhE) was the only by-product. Conditions: 160°C, 60 bar hydrogen pressure, 3 h reaction time.

Scheme 1

Hydrodeoxygenation of acetophenone.