Study of the Interaction of Ethanol with the Bronsted and Lewis Acid Sites on Metal Oxide Surfaces Using the DV-X.ALPHA. Method.

Abstract

The interactions of EtOH with a Bronsted acid site (a hydroxy group) and with a Lewis acid site (a metal ion) on surface of 7 metal oxides (SiO2-Al2O3, SiO2, TiO2, ZnO, MgO, MnO, and CdO) were investigated using the DV-Xα method. The oxides were selected from a series of catalysts, whose selectivities for the dehydration and the dehydrogenation of EtOH were exptl. detd. by P. Sabatier and A. Maihe. By comparing the results of the DV-Xα calcns. from several models of EtOH interacting with the Bronsted or Lewis acid sites with the exptl. selectivities, it was concluded that a proton shift from the Bronsted site to the EtOH O occurs when EtOH strongly interacts with the site and that this shift changed the electronic state of EtOH to be favorable to dehydration. Thus, the dehydration of EtOH on oxide catalysts proceeds by the E1 mechanism. [on SciFinder(R)]