Dehydration reactions play an important role to convert biomass-derived alcohols (e.g. ethanol) to value-added chemicals (e.g. ethylene, an important building block for the production of polymers). Dehydration chemistry on metal-oxide catalysts has been an area of research for more than half a century now, albeit, with contradictory results. Prof. Mpourmpakis’ group at Pitt developed a theoretical model based on quantum chemical calculations that relates the dehydration activity with key physicochemical properties of the metal oxides (catalysts) and the alcohols (reactants). These descriptors are the catalyst’s surface Lewis acidity (alcohol binding energy on the metals) and basicity (proton affinity of the surface oxygens or hydroxyl-groups) and the carbenium ion stability of the alcohols. The model’s predictions were further verified by dehydration experiments in Prof. Raymond Gorte’s lab at the University of Pennsylvania. The ramification of this simple, but yet very powerful model is that we can apply it to screen a variety of different alcohols and metal-oxide catalysts according to their dehydration activity, avoiding trial-and-error experiments in the lab.
Publication source: http://pubs.rsc.org/en/content/articlelanding/2014/cy/c4cy00632a