Influence of H+ Contents of Support on CuY Catalyst for Catalytic Performances of Oxidative Carbonylation of Methanol

A series of Y zeolite supported Cu catalysts (CuY) with Cu loading of 6.4% were prepared by wet impregnation method and investigated in oxidative carbonylation of methanol. The microstructure and surface properties of the catalysts were characterized by X-ray diffraction (XRD), H-2-temperature program reduction (H-2-TPR), NH3-temperature program desorption (NH3-TPD), transmission electron microscope(TEM) techniques. With the increase of H+ content, the Y zeolite supports were more conductive to the cation exchangment with Cu2+, leading to well dispersed Cu species in cages. Above all, the non-exchanged Na+ of Y zeolite resulted in more Cu species located in the super cages. After calcination, the copper species converted into Cu+, which enhanced the catalytic activity of oxidative carbonylation of methanol. The introduction of Cu species into Y zeolite produced moderate acid sites and the amount of acid was also increased with the increase of Cu species located in the cages, As a result, the reaction product distribution varied and the selectivity of DMC decreased with the increase of H+ content. The CuY catalyst prepared by incipient-wetness impregnation method gave 92.3% selectivity of DMC, whereas the Cu catalyst supported on NaY zeolite by wet impregnation method gave 82.4% selectivity of DMC and high space-time yield (STY) of DMC, 109.1 mg .g(-1).h(-1).