ChemInform Abstract: Characterization of the Surface Acid-Base Properties of Metal Oxides by Titration/ Displacement Reactions.
Abstract
The relative acidities of a series of Brönsted acids (MeSH, PhSH, MeOH, EtOH, PhOH, HCOOH, MeCOOH, HCN, HCCH, PhCCH) have been determined by titration/displacement reactions on powdered samples of ZnO and MgO.
ChemInform Abstract
The relative acidities of a series of Brönsted acids (MeSH, PhSH, MeOH, EtOH, PhOH, HCOOH, MeCOOH, HCN, HCCH, PhCCH) have been determined by titration/displacement reactions on powdered samples of ZnO and MgO. In contrast to previous results obtained on the Ag(l l0) surface, the relative acidity scales on the oxides are in better agreement with aqueous dissociation constants than with the gas-phase acidity scale. This effect is explained by a strong interaction between adsorbed conjugate base species and surface metal cations which results in some covalent bond formation. The relative magnitudes of these surface-adsorbate interactions are consistent with trends suggested by the principles of hard and soft acid-base interactions.
