Dimethyl carbonate synthesis from methyl nitrite and CO over activated carbon supported Wacker-type catalysts: The surface chemistry of activated carbon

Abstract

A series of supported Wacker-type catalysts under treatment of nitric acid were prepared and utilized in the synthesis of dimethyl carbonate from CO and methyl nitrite. Nitrogen adsorption, Boehm titration, scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and H2-temperature-programmed reduction (H2-TPR) were employed to explore the relationship between the physicochemical properties and reactivity of catalysts. Correlated with the results of Boehm titration, it was found that catalytic activities increased monotonically with the number of phenolic group on activated carbon surface. XPS spectra showed that the catalysts, which had much more amount of phenolic group, were possessed of large amount of Cu2+ species. H2-TPR results indicated that the phenolic group contributed to the easier reducibility of Cu2+ species, further facilitating the oxidation cycle between Pd and Cu species and consequently the catalytic performance.