Selective production of γ-Valerolactone from ethyl levulinate by catalytic transfer hydrogenation over Zr-based catalyst

The catalytic transfer hydrogenation (CTH) reaction of ethyl levulinate (EL) with alcohol to γ-valerolactone (GVL) has been investigated over a series of Zr-based catalysts, including ZrO 2 , ZrP, Zrβ, ZrP/Hβ and ZrO 2 /HZSM-5. It is found that the simplest ZrO 2 was the most efficient for GVL production, giving an EL conversion as high as 97% and GVL selectivity of 91% after 7 h at 170 °C using 2-propanol as the hydrogen donor and solvent. The effects of reaction temperature, time and solvent on catalytic performance were investigated. Moreover, the kinetic behavior of CTH reaction of EL was also studied over ZrO 2 catalyst. The as-prepared ZrO 2 gives an Ea value of 32.9 kJ/mol, which is much lower than other catalysts in the literatures. Furthermore, those catalysts have been, respectively, characterized by XRD, IR, BET and NH 3 -TPD techniques to reveal the physical properties and structures of these materials. Correlating the catalyst performance with its physical and chemical properties uncovers that the higher pore diameter, lower total acidity and higher Lewis acid sites of catalyst surface would be the key to the catalyst performance. Graphical abstract