Efficient Promotional Effects of Mo on the Catalytic Hydrogenation of Methyl Acrylate over Ni-Based Catalysts under Mild Conditions

A series of Ni/gamma-Al2O3 and Ni-Mo/gamma-Al2O3 catalysts were prepared and evaluated for the hydrogenation of methyl acrylate to methyl propionate in a fixed-bed reactor. Physicochemical characterizations of these catalysts were carried out with Brunauer-Emmett-Teller analysis, X-ray diffraction, UV-vis diffuse reflectance spectroscopy, Raman spectroscopy, hydrogen temperature programed reduction, X-ray photoelectron spectroscopy, and transmission electron microscopy. It was noticed that Mo loaded onto the Ni/gamma-Al2O3 catalyst could not only promote the dispersion of Ni particles but also weaken the interaction between NiO and the gamma-Al2O3 support. The effect of the calcination temperature on Ni-Mo/gamma-Al2O3 catalysts is mainly due to the enhancement of the interaction between Ni species and gamma-Al2O3. The influence of the reduction temperature on the Ni-Mo/gamma-Al2O3 catalysts, as well as the reaction conditions, was also studied in detail. As a result, this hydrogenation process could be efficiently promoted on the optimal 10Ni-10Mo/gamma-Al2O3 catalyst with the highest yield of 94% and selectivity of 99.9%, and no deactivation behavior was observed after 130 h time-on-stream at 100 degrees C and 1.0 MPa.