Selective Hydrogenation of Maleic Anhydride to Succinic Anhydride in Liquid Phase over Ni-Cu/Al<SUB>2</SUB>O<SUB>3</SUB> Catalyst

A series of Ni-Cu/Al2O3 catalyst samples were prepared by the wetness impregnation method and characterized by N2 physisorption, H2 temperature-programmed reduction, H2 temperature-programmed desorption, X-ray diffraction, and CO temperature-programmed surface reaction. Their catalytic performance in the liquid phase hydrogenation of maleic anhydride was investigated. The results indicated that the particle size of nickel crystallites was reduced, and the nickel species was well dispersed. Then, the C=C hydrogenation activity was significantly improved when the catalyst was promoted by Cu. However, due to the interaction between Ni and Cu, the C=O hydrogenation was retarded. The combination of the above two factors led to high selectivity for succinic anhydride over 15%Ni-7%Cu/Al2O3 catalyst. The conversion of maleic anhydride and selectivity for succinic anhydride reached 100% under the reaction conditions of 5 MPa hydrogen pressure and 210 oC for 40 min.