Study On Hydrogenation Of Levulinic Acid Synthesisγ-valerolactone Catalysts And Process

The biomass platform molecules levulinic acid hydrogenation conversion to gamma-valerolactone, that is the key steps of the conversion of biomass to liquid fuels and the carbon-based chemicals, and has important environmental and practical significance. Hydrogenation of levulinic acid to gamma-valerolactone, the key lies in the choice of catalysts, which directly affect the reaction effects and prospects for industrial applications.Based on Raney Cu, The experiments studied copper aluminum alloy activation conditions including NaOH concentration, activation time, activation temperature, and also investigated the suitable reaction conditions, designed experiments which repeated the use of catalysts in different solvents, and analyze the mechanism of the decreased activity through BET, XRD, TEM, and other means to characterize the nature of the changes between the fresh and used catalysts; The experiments study other catalysts, including a precious metal catalyst Ru/C, Raney Ni, Raney Co, CuO-Cr2O3, CuO/SiO2, six different elements of Raney Cu.Under the experimental conditions, the experimental results show that the suitable activation temperature is70℃, and the activation time islh, alloy:NaOH:water (mass ratio)=1:1.5:5; suitable reaction conditions:copper-aluminum alloy/levulinic acid=4/25(g/ml), using dioxane as the solvent, acidic alumina/reaction liquid=lg/200mL,the reaction pressure to3MPa, by adding NaOH, the reaction temperature is135℃, without additives, the reaction temperature is155℃.By characterization of the catalyst, the experiment infers the possible mechanism of decreased activity:levulinic acid reacts with Cu, Fe, Ni to metal saltsa and these salts are soluble in water but only sparingly soluble in levulinic acid and other organic phase, the esterification water can not completely dissolve the metal salts, which are deposited on the catalyst. On one hand, metal salts caused the loss of the active ingredient, on the other hand, the deposition of metal salts result in reduced aperture.In order to illustrate the better catalytic effect of the Raney Cu catalyst, the experiments make comparison with several other catalysts. The study found a high but expensive activity of precious metals; poor acid resistance of the Raney Ni and Raney Co; the industrial grade catalyst CuO-Cr2O3shows good catalytic hydrogenation of levulinic acid, but chromium is carcinogenic, and pollutes the environment...