Abstract: Al-based slurry catalysts using pseudo-boehmite as aluminum source were prepared by a complete liquid-phase technology and the catalyst precursors were modified by different drying control chemical additives(DCCAs). The catalysts were characterized by means of X-ray diffraction, N₂ adsorption, X-ray photoelectron spectroscopy and H₂ temperature-programmed reduction. The performance of the catalysts was evaluated in a slurry reactor for the synthesis of dimethyl ether(DME) from syngas. The results indicate that using pseudo-boehmite as aluminum source there takes place a strong interaction between copper and aluminum, which induce the formation of CuAl₂O₄ and decrease the amount of reducible Cu₂O. Consequently, the catalyst activity is decreased. Further study shows that the DCCA influences significantly on catalyst's property. When the catalyst precursors are modified by glycerol as DCCA, the catalysts surface area and mean pore size are increased. The active component of the catalyst is dispersed uniformly and the formation of CuAl₂O₄ is suppressed, meanwhile, the reducible Cu₂O is increased. Therefore, the catalyst shows the highest space time yield and selectivity of dimethyl ether.

Key words: Complete liquid-phase technology, Pseudo-boehmite, Dimethyl ether, Drying control chemical additive(DCCA), Slurry catalyst