Copper-basic sites synergic effect on the ethanol dehydrogenation and condensation reactions

Abstract

Bioethanol upgrading through condensation is of key interest in the development of sustainable processes, shifting from fossil to renewable carbon. Here, a new strategy is proposed, which combines in one catalyst an appropriate distribution of acid/ basic sites of a mixed oxide with the presence of an active dehydrogenation phase (Cu nanoparticles). Experiments, performed in a fixed bed reactor, reveal a very positive effect of Cu in the performance of Mg@Al catalyst, with 1-butanol productivity 12 times higher at 523K under inert conditions. The improvement is even more notable in presence of H2, almost 30 times higher, under same conditions. The presence of Cu on the surface increases the formation of acetaldehyde, limiting the extent of dehydration side-reactions. In addition, hydrogen enhances the C4 hydrogenation, preventing oligomerizations and inhibiting decarbonylation steps that are directly related to the catalytic deactivation by poisoning.