Acetone from ethanol employing ZnxZr1−xO2−y

Abstract

The main purpose of this work is to contribute to the description of the acetone synthesis from ethanol employing ZnxZr1-xO2-y based catalysts. The catalytic behavior of these solids was evaluated (isoconversion) in the acetone synthesis. The most active catalyst and m-ZrO2 (used as a reference) were characterized by the following techniques: pyridine adsorption, TPD of NH3, TPD of CO2, TPD of ethanol followed by IR (DRIFTS)/MS, TPD of ethanol followed by XANES at the Zr K-edge and Zn K-edge and XRD in situ. The present study suggests that the main steps of the acetone generation from ethanol are the following: firstly, ethoxide species are generated and, then, they are dehydrogenated to acetaldehyde. Both steps are related to strong basic and acid sites. Acetaldehyde reacts with the O of the solid solution generating acetate species and vacancies on the catalyst surface. These carboxylate species condensate (strong basic sites) and generate acetone and CO2. Water dissociates on the vacancies of the catalyst and reoxidizes the its surface, closing the catalytic cycle. All these steps might occur on Zn+2 and on the species in its vicinity (XANES).