关键词: 催化, 加氢, 载体改性, 铜, 醋酸仲丁酯, 仲丁醇

Abstract:

Cu-based catalysts(Cu/B/M/Al₂O₃, M = Mg, Ca, Ni)supported on the modified γ-Al₂O₃ by incorporating MgO, CaO or NiO were prepared by an incipient wetness impregnation method, of which each active component was solely deposited on support. The catalysts were characterized by scanning electron microscopy(SEM), X-ray diffraction(XRD), NH₃ temperature-programmed desorption(NH₃-TPD), H₂ temperature-programmed reduction(H₂-TPR)and X-ray photoelectron spectroscopy(XPS)techniques. It showed that effects of the modifications of γ-Al₂O₃ support with varied metal oxides on the structure of Cu-based catalysts and the catalytic performances for the hydrogenation of sec-butyl acetate(SBA)were significant. NiO-modified catalysts exhibited dramatic increases in the yields of both ethyl acetate and butane, due to the intrinsic activity of Ni metal for alkene hydrogenation and the acidic support beneficial to transesterification and sec-butanol dehydration, while the modification with MgO resulted in a poor dispersion of Cu metal on support and an inferior catalyst stability for the SBA hydrogenation. For above two catalysts, the modification of NiO or MgO was conducted after loading B₂O₃ and Cu precursors on support. On the contrary, the modification with CaO was done before loading B₂O₃ and Cu precursors, which facilitated the Cu dispersion on support and improved both SBA conversions and the selectivity to sec-butanol. Moreover, formation and accumulation of non-reactive carbonaceous species on the surface of CaO-modified catalyst might be effectively minimized.

Key words: catalysis, hydrogenation, support modification, copper, sec-butyl acetate, sec-butanol