Tio₂/MgO-Mischkatalysatoren: Teil II. infrarotuntersuchungen

The acidic properties of MgO/TiO₂ mixed oxides have been investigated by means of IR spectroscopy adsorbing aceton and Pyridine. Beside the adsorption of aceton on hydroxyl groups, strongjnteractions with cations have been observed. The latter form of adsorption was bound to form carboxylic structures on the surface. The shift of hydroxyl bands after adsorption of aceton decreased with increasing Mg content, which indicates decreasing acid strength. No condensation reactions of adsorbed aceton molecules have taken place. The band of coordinatively bound pyridine was split, indicating different Lewis acid centers. The band with the lower wavelength was less stable than the other one. Independent of degree of hydroxylation the catalysts showed no Brönsted acidity.