Synthesis and characterization of solid base mesoporous and microporous catalysts: Influence of the support, structure and type of base metal

Synthesis of solid base Ce–H-MCM-41, Ce–Si-MCM-41, Cs-MCM-41, K-MCM-41 mesoporous materials and Na-ZSM-12, Cs-ZSM-12 microporous zeolites were carried out by means of evaporation impregnation and ion-exchange methods. The solid base catalysts were characterized using X-ray powder diffraction, scanning electron microscope, nitrogen adsorption, FTIR of pyridine and temperature programmed desorption of CO2. The H-ZSM-12, Cs-ZSM-12 zeolite, H-MCM-41, Ce–H-MCM-41 and Ce–Si-MCM-41 mesoporous catalysts were studied for the synthesis of diethyl carbonate starting from ethanol and carbon dioxide, using butylene oxide as the dehydrating agent. Catalyst testing for the synthesis of diethyl carbonate was carried out at 170 °C and 4.5 MPa of initial CO2 pressure. 16 wt.% Ce–H-MCM-41 mesoporous material exhibited higher amount of weak, medium and strong basic sites than that of 32 wt.% Ce–Si-MCM-41. The presence of weak and strong basic sites was observed in the microporous 2 wt.% Cs-ZSM-12 catalyst. Diethyl carbonate formation was observed over Ce–H-MCM-41 and Ce–Si-MCM-41 mesoporous materials. Amount of basic sites and its strength influenced the synthesis of diethyl carbonate over the mesoporous materials.

Direct synthesis of diethyl carbonate starting from ethanol and carbon dioxide (Eq. (1)) over solid base microporous and mesoporous materials have been studied:equation(1)2C2H5OH+CO2⇌(C2H5O)2CO+H2O2C2H5OH+CO2⇌(C2H5O)2CO+H2ODetermination of basic sites in solid base microporous and mesoporous materials have been studied by temperature programmed desorption of carbon dioxide.Figure optionsDownload as PowerPoint slideHighlights
► Synthesis of solid base microporous and ordered mesoporous catalysts.
► Quantitative determination of different types of basic sites using CO2 TPD.
► Synthesis of diethyl carbonate using ethanol and CO2 over solid base catalysts.
► Influence of type of basic sites on formation of diethyl carbonate.
► Type of base metal and support effect synthesis of diethyl carbonate.