Estudo de catalisadores, a base de óxidos de zinco e cálcio, para a reação de obtenção de acetona a partir de misturas etanol-água.

Abstract

The reaction of transformation of aqueous solution of ethanol for production of acetone in the presence of massic catalysts composed of pure zinc oxide, pure calcium oxide and steochiometric mixtures of them was studied to optimize the conditions of preparation of these catalysts and the operational characteristcs of this process, and also to propose a possible mechanism for this reaction. The synthesized catalysts were characterized by Chemical Analysis (CA), X-ray diffraction (XRD), Specific Area (SA), Thermogravimetric and thermodifferential Analysis (ATG/ATD) and isoeletric point measurement (IEP). The catalytic activity of these catalysts was evaluated for the reaction of hydrated ethanol with a catalytic test composed of a fixed bed glass microreactor, into which the reagents were admitted vapours at a pressure close to the equilibrium vapour pressure of the reactional mixture at ambient pressure. The results of this work show that catalysts based on chlorine salts are more active and selective, for the formation of acetone, than those based on nitrates, and that there is a strong correlation between the types of sites (acidic/basic) found in these synthesized compounds and the orientation of the reaction for the maximization of the production of acetone. Finally, the reaction of formation of acetaldehyde is proposed as one of the possible intermediate steps of the global reaction process.