Improved activity of a CaCO3-supported Ru catalyst for the hydrodeoxygenation of eugenol as a model lignin-derived phenolic compound

A calcium carbonate (CaCO3)-supported Ru catalyst (Ru/CaCO3) prepared by a wet impregnation method was used for the hydrodeoxygenation (HDO) of eugenol, a lignin model compound representing coniferyl alcohols, and was shown to surpass Ru supported on neutral (ZrO2) and basic supports (MgAlOx, hydrotalcite, and MgO) in terms of deoxygenation activity. The production of deoxygenated compounds was observed during the batch reduction of eugenol with H2 (room-temperature-equivalent pressure = 50 bar) over Ru/CaCO3 at 250 °C, and the yields of compounds with no oxygen atoms (0-O) and one oxygen atom (1-O) were determined as 25.5 and 48.2%, respectively. X-ray photoelectron spectroscopy revealed that the improved hydrodeoxygenation activity could be ascribed to the increased electron density of catalytically active Ru species because of electron donation from the support.