Ru-La/γ-Al2O3 catalyst was prepared by impregnation method and characterized by temperature pro- grammed reduction（TPR）, transmission electron microscopy（TEM）, X-ray photoelectron spectra（XPS）, Brunauer- Emmett-Teller（BET）, X-ray diffraction（XRD）, and NH3-temperature programmed desorption（NH3-TPD）. NH3-TPD revealed that the strong acidic centers in γ-Al2O3 are not the major factor to cause the hydrolysis of esters to acids in the hydrogenation of esters. The results of TPR and TEM indicate that the appropriately added lanthanum results in the good dispersion of ruthenium and the easy reduction of ruthenium oxide on Ru-Laγ-Al2O3, which could promote the catalytic activity of Ru-La/γ-Al2O3 for the hydrogenation of methyl propionate to propanol. When the amount of lanthanum added in the catalyst was up to 9%（mass fraction）, 4%Ru-9%La/γ-Al2O3 catalyst gave a conversion of methyl propionate of 98.1% and a selectivity of 94.8% to propanol at a reaction temperature of 180℃ and a hydro- gen pressure of 5.0 MPa.
Hydrous zirconia supported ruthenium catalyst Ru/ZrO2 xH2O, prepared by co-precipitating ruthenium trichloride and zirconium oxychloride with ammonia, was able to catalyze efficiently methyl propionate to propanol under the mild conditions. In aqueous system, the propanol yield of 〉99% was achieved under the conditions of reaction temperature of 150 ℃ and hydrogen pressure of 5.0 MPa, while in non-aqueous system the maximum propanol yield was only 47.0%. FTIR spectra and hydrogenation results indicated that the high catalytic performance of Ru/ZrO2 xH2O in aqueous phase results from the cooperation effect between water as a solvent and hydroxyl groups on the surtace of carrier.
Fan GuangyinZhou YafenFu HaiyanYe XiaoliLi RuixiangChen HuaLi Xianjun
