Dehydrogenation and Diels–Alder reactions in a one-pot synthesis of benzaldehyde from n-butane over acid catalysts

VOx/ZrO2/SiO2 catalysts were synthesized via grafting of vanadium and zirconium alkoxides over Aerosil 380. With these materials the formation of benzaldehyde from butane was possible in a one-pot synthesis, where oxidative dehydrogenation (ODH) for the formation of butadiene is coupled with a Diels–Alder reaction for the formation of benzaldehyde. Experiments performed with a catalyst where the support was modified with Ce instead of Zr, give a material that under the reaction conditions studied does not yield benzaldehyde, showing that acidity plays an important role in the formation of this compound.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Benzaldehyde was produced from n-butane in a one-pot synthesis at 400 °C. ► The reaction occurred over vanadium supported on Ce or Zr modified SiO2. ► The formation of benzaldehyde occurred only on catalysts with acid sites. ► Catalysts with strong acid sites showed high selectivity to CO and CO2. ► The reaction network consists of Diels–Alder and oxidative dehydrogenation steps.