Catalytic conversion of ethanol and isopropanol over the Mn 2O 3/Al 2O 3 system doped with Na 2O

Abstract

Pure and Na 2O-doped Mn 2O 3/Al 2O 3 solids were prepared by heating pure and NaNO 3-treated MnCO 3/Al(OH) 3 mixed solids at 500 °C. The nominal composition of the calcined pure solids was 0.1 Mn 2O 3/Al 2O 3 and the dopant concentration varied between 0.75 and 6 mol% Na 2O. The physicochemical surface and catalytic properties of pure and doped solids were investigated using X-ray powder diffraction (XRD), FTIR nitrogen adsorption at −196 °C and conversion of ethanol and isopropanol at 200–350 °C using the micropulse technique. The obtained results showed that the treatment of the Mn 2O 3/Al 2O 3 system with Na 2O (3 or 6 mol%) followed by heating at 500 °C led to the formation of the sodium manganese oxide (Na 0.2MnO 2) phase. This treatment effected the decrease in the BET surface areas of the treated solids and led to an effective increase in their catalytic activities. The addition of 3 mol% Na 2O brought about a significant increase in the percentage conversion (dehydration) of both alcohols measured at 300 °C from 22% to 92% and from 40% to 97% for ethanol and isopropanol, respectively.