Selective oxidation of alcohols with molecular oxygen over Ru/CaO–ZrO2 catalyst

Selective oxidation of alcohols to carbonyl compounds with molecular oxygen was carried out over ruthenium supported on a CaO–ZrO2 solid solution prepared by the co-precipitation method. In the oxidation of benzyl alcohol, the Ru/CaO–ZrO2 catalyst gave benzaldehyde in a yield higher than 98% at 90 °C, and the turnover frequency reached 224 h−1. The Ru/CaO–ZrO2 catalyst also exhibited high catalytic activities and selectivities to carbonyl compounds in the oxidation of aromatic ring-substituted benzylic, allylic, and aliphatic alcohols. Moreover, this catalyst exhibited high activities in the oxidation of alcohols at a low temperature (40 °C). The catalytic activity and oxidation state of ruthenium depended on the Ca/Zr molar ratio of the support, and the highest catalytic activity was obtained with Ca/Zr = 0.125. DRIFT and XPS analyses revealed that Run+–OH (n = 3, 4) on the surface of CaO–ZrO2 were likely the active species in the oxidation of alcohols.

Graphical abstractAerobic oxidation of alcohols was successfully carried out by the RuCl3 loaded on CaO–ZrO2 basic solid solution supported catalyst.Figure optionsDownload full-size imageDownload high-quality image (83 K)Download as PowerPoint slide