Catalytic Hydrocracking of -C-O-Bridged Bonds over Mg2Si/γ-Al2O3 Catalyst

Nano γ-Al 2 O 3 support was prepared by sol-gel method, and the Mg 2 Si/γ-Al 2 O 3 catalyst was prepared by impregnation method from Mg 2 Si and the γ-Al 2 O 3 support. The catalyst was characterized by X-ray diffraction, N 2 adsorption-desorption, scanning electron microscopy and CO 2 temperature-programmed desorption analysis. The catalytic hydrocracking of lignite-related modelcompounds, 1-methoxynaphthalene (1-MON) and bibenzyl ether (BE), was investigated. Mg 2 Si was well distributed on the surface and in the voids of γ-Al 2 O 3 support. The Mg 2 Si/γ-Al 2 O 3 catalyst had high specific surface area, large amount of mesopores, strong basicity, and exhibited high catalytic efficiency in hydrocracking of 1-MON and BE due to the synergic effect between Mg 2 Si and γ-Al 2 O 3 . Under an initial hydrogen pressure of 3 MPa and reaction time of 60 min, the conversion of 1-MON and BE reached 100% when the reaction temperatures were 225 and 175°C, respectively. The selectivities for naphthalene and toluene were close to 100%, only traces of the hydrogenated products were detected. After 4 cycle tests, the catalytic activity of Mg 2 Si/γ-Al 2 O 3 catalystdropped to 50%.