Conversion Of Succinic Acid Over Ni And Co Catalysts

Liquid-phase hydrogenation of succinic acid (SA) over supported Ni and Co catalysts was investigated at 200 degrees C and 6 MPa of H-2. Reduced and passivated catalysts with the same surface metal density (2.5 atoms of metal per nm(2) of support) were prepared by incipient wetness impregnation. The catalysts were characterized by X-ray diffraction (XRD), N-2 adsorption, X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction (TPR), CO-chemisorption, and temperature-programmed desorption of NH3 (TPD-NH3). The Ni and Co catalysts supported over SiO2 showed different product distribution, due to the adsorption of the SA over the surface of catalysts, determined by DFT calculations. The Co/SiO2, Co/SiO2-Al2O3, and Co/Al2O3 catalysts showed different product distribution, which was correlated with total acidity from TPD-NH3 results. In general, the Co catalysts promoted the hydrogenation process; however, the highest total acidity showed by Co/Al2O3 also promoted the dehydration process. Finally, the initial rate follows the trend according to the dispersion determined by COchemisorption.