Effect of the acid–base properties of the support on the performance of Pt catalysts in the partial hydrogenation of citral

In this work, the effect that mesoporous solid materials, with different acid–base properties (Pt-1 wt%/acid or base) have over the product distribution during the partial hydrogenation of citral was evaluated. It was found that basic materials were the most active catalysts reaching a 100% citral conversion after 1 h of reaction. Regarding selectivity, in basic materials (Pt/MgAl-c and Pt/MgAl-r) citronellal was the main product, while nerol and geraniol were produced in acid solids (Pt/SiO2; Pt/SiO2–TiO2 and Pt/SiO2–ZrO2). The formation of unsaturated alcohols is related to the strength and density of the acid sites of the catalyst and in this sense the Pt/SiO2–ZrO2 gave a yield of 80%. The acidity trend is: Pt/SiO2–ZrO2 > Pt/SiO2–TiO2 > Pt/SiO2 > Pt/MgAl-c.