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Keywords:

  • alcohols;
  • gold;
  • hydrogenation;
  • nanostructures;
  • supported catalysts

Abstract

Gold(0) catalysts supported on ferric oxide are effective catalysts, and so far, the only heterogeneous ones known for the regioselective hydrogenation of α,β-unsaturated ketones to the corresponding α,β-unsaturated secondary alcohols. A set of ferric oxide samples, synthesized under strictly controlled conditions and thoroughly characterized (X-ray powder diffraction, Mössbauer spectroscopy, micro-Raman spectroscopy, transmission electron microscopy, temperature-programmed reduction), were employed as supports of gold(0) catalysts for this reaction. The activity and selectivity of the catalysts changed in the same direction from one catalyst to another; increasing fractions of nanostructured ferric oxide phases in the support (with nanoparticles size lower than 10 nm) increased both. With a 4 % gold catalyst supported on the ferric oxide sample containing the highest proportion of nanostructured matter, we achieved a selectivity of 66 % towards the unsaturated alcohol at more than 90 % conversion in the hydrogenation of benzalacetone (ethanol, 60 °C, 103 kPa), which is one of the best performances ever reported for this reaction.