Nitrogen-doped carbon supported ZnO as highly stable heterogeneous catalysts for transesterification synthesis of...

Nitrogen-doped carbon material (NCM) supported ZnO catalysts were prepared by wet impregnation method, following a high-temperature thermal treatment process. The resultant ZnO/NCM catalysts calcined at different temperatures were characterized by X-ray diffraction (XRD), Raman spectroscopy, N₂ adsorption-desorption, elemental analysis, X-ray photoelectron spectroscopy (XPS) to investigate their physicochemical properties and the interaction between ZnO and NCM support. Their catalytic properties were studied by liquid phase transesterification of dimethyl carbonate (DMC) with diethyl carbonate (DEC). Of these the catalyst calcined at 800 °C, named ZnO/NCM-800 exhibits the highest catalytic activity, as well as excellent stability and recyclability for the synthesis of ethyl methyl carbonate (EMC). The NCM support possesses abundant mesopores, rich surface oxygen-containing and nitrogen-containing functional groups, which are beneficial to build relatively strong interaction between ZnO nanoparticles and the NCM support, resulting in the generation of a highly active and stable acidic-basic bifunctional catalyst for the transesterification of DMC with DEC.