It has been shown that yttria-stabilized zirconia is an effective catalyst for ethanol to n-butanol Guerbet coupling. The variation of the calcination temperature allows an improvement in the catalytic characteristics of this material via stabilization of the tetragonal phase of zirconia, having higher basicity than the monoclinic one. The treatment of yttria-stabilized zirconia at an optimal calcination temperature of 500 °C induces the increase in surface basicity required for the aldol condensation step, along with a decrease in surface acidity, which is responsible for the side reaction such as ethylene formation. The catalyst obtained significantly exceeds in selectivity and n-butanol yield than individual zirconia and other oxide systems which have been studied in this reaction.
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