Preparation method of catalyst for synthesizing dimethyl carbonate

The invention provides a preparation method of a catalyst for synthesizing dimethyl carbonate, which comprises the following steps: impregnating a spherical gamma-Al2O3 carrier by adopting an aqueous solution of chlorides or nitrates of alkali metal Li, Na and K elements in an impregnation manner, drying after impregnation, and roasting to obtain a gamma-Al2O3 modified carrier; the preparation method comprises the following steps: taking a PdCl2 solid and a CuCl2. 2H2O crystal, adding ammonia water, stirring and dissolving to form a transparent solution, namely a Pd-Cu impregnation liquid; taking the gamma-Al2O3 modified carrier, uniformly spraying the Pd-Cu impregnation liquid onto the gamma-Al2O3 modified carrier in an equivalent-volume impregnation manner, drying after impregnation, and roasting in air after drying to obtain the synthetic DMC catalyst. The impregnation liquid is prepared from the active metal in an ammoxidation mode, the impregnation liquid is alkaline, the active metal is more easily adso