SURFACE CHARACTERISTICS AND CATALYTIC ACTIVITY OF BINARY OXIDES OF ALUMINA-YTTRIA

A series of different compositions of Al2O3-Y2O3 catalysts were prepar ed by coprecipitation with aqueous ammonia. The structure, thermal sta bility and surface properties of the catalysts were determined using X RD, TGA, SEM and MAS 27AlNMR. Acidity and basicity of catalysts were d etermined using Hammett indicators and surface area by BET method. Sur face area and Bronsted acidity of the catalysts decreased with increas ing amount of Y2O3. No basic sites were observed over catalyst samples with higher Y2O3 content. (+)-Limonene oxide isomerization was carrie d out at 100-degrees-C over the catalysts. The activity and selectivit y of catalysts varied with composition. Catalysts with high alumina co ntent yielded more diol while less alumina containing samples produced more ketones.