A bicomponent catalyst for the selective formation of ethanol from synthesis gas

Multipromoted Rh-Mn-Li/SiO₂ and Rh-Ir-Mn-Li/SiO₂ catalysts for the selective hydrogenation of carbon monoxide to oxygenates have been combined with a selective hydrogenation component CuO-ZnO/SiO₂ to produce ethanol with high activity and selectivity. Different degrees of mixing the two components, including a simultaneous impregnation of all components, have been applied to elucidate their mutual influence. It has been shown by temperature-programmed reduction (TPR) that the differences in the catalytic behavior could be explained by the different extent of mutual influence of dependence on the degree of mixing. To avoid a poisoning effect of zinc and/or copper to the active sites of rhodium, the mixture of the two components should not be too intimate.