Impact of preparation strategy on the properties of carbon-supported Wacker-type catalysts in vapor-phase dimethyl carbonate synthesis Original Research Article

Four supported Wacker-type catalysts were prepared by varying impregnation solvents and sequences of activated carbon. The catalysts were characterized by BET, XRD, SEM/EDXS, and TPR. They were tested for the dimethyl carbonate (DMC) synthesis from vapor-phase oxidative carbonylation of methanol. The results show that the preparation procedures have an impact on the reducibility, surface morphology as well as on the spatial distribution of the active-phase particles at the exterior of the carbon grains. Concerning the activity, the catalyst prepared by impregnating the carbon support with KOAc followed by PdCl2/CuCl2 employing ethanol as the impregnation solvent shows a higher performance in the oxidative carbonylation of methanol. The improved performance of the catalyst for methanol conversion to DMC can be attributed to the presence of a high surface concentration of an active phase comprising Pd and Cu species in close vicinity deposited on the external part of the carbon support.