Research on the vapor phase oxidative carbonylation of methanol to dimethyl carbonate over Cu/zeolite with different Si/Al

摘要

Cu/zeolite catalysts were prepared by solid state ion exchange and used to catalyze the vapor- phase oxidative carbonylation of methanol to dimethyl carbonate. As Hβ and HZSM-5 were supports ,the effect of SiO2/Al2O3 ratio was investigated, the result showed that either Hβ or HZSM-5 were support ,the catalytic activity increase with decreasing of ratio of SiO2/Al2O3. The effect of kinds of zeolite was also studied ,it is showed that the kinds of zeolite had remarkable influence on the catalytic activity. The zeolite with low ratio of SiO2/Al2O3 show high catalytic activity for oxidative carbonylation of methanol. By combind XRD and EDX characterization, it is found that the degree of ion-exchange increased with mole ratio of Si/Al increasing. When DASY(2.0) was used as support to ion-exchange with CuCl, the reaction runs more completely, no CuCl diffraction peak was observed from XRD spectra, and less Cl was exist on the catalyst surface.This further testified that ratio of SiO2/Al2O3 of zeolite decrease and the number of H + of Brβ nsted acid increase, so in preparation of catalysts the number of Cu I exchanged increase , that attrite to the improvement of catalytic activity.