Hydrogenation of Levulinic Acid over Nickel Catalysts Supported on Aluminum Oxide to Prepare gamma-Valerolactone

Four types of nickel catalysts supported on aluminum oxide (Ni/Al2O3) with different nickel loadings were synthesized using the co-precipitation method and were used for the hydrogenation of levulinic acid (LA) to prepare -valerolactone (GVL). The synthesized Ni/Al2O3 catalysts exhibited excellent catalytic activity in dioxane, and the activity of the catalysts was excellent even after being used four times in dioxane. The catalytic activity in dioxane as a solvent was found to be superior to the activity in water. Nitrogen physisorption, X-ray diffraction, and transmission electron microscopy were employed to characterize the fresh and used catalysts. The effects of the nickel loading, temperature, hydrogen pressure, and substrate/catalyst ratio on the catalytic activity were investigated.