Effect of syngas conversion and catalyst reduction temperature in the synthesis of ethanol: concentration of water vapor in mesoporous Rh/MCM-41 catalyst

Rh-based catalysts typically show low selectivity to CO2 in the synthesis of ethanol from syngas. However, a novel mesoporous Rh/MCM-41 catalyst shows high selectivity to CO2 in a large range of syngas conversions; 1% to 68%, regulated by adjusting the operation conditions (270-430 degrees C, 30-90 bar and 6000-40,000 ml(syngas)/gcat h). The same effect is obtained at different catalyst reduction temperatures (200 degrees C and 500 degrees C) as well as on the non-reduced catalyst. A high concentration of water vapor seems to occur in the pores of Rh/MCM-41 which may promote the water-gas-shift-reaction, producing extra CO2 and H-2. (C) 2015 Elsevier B.V. All rights reserved.