Abstract
Alumina, magnesia and alumina-magnesia catalysts of different chemical compositions were prepared. The textural properties were obtained from low temperature nitrogen adsorption and the solid phases were detected by x-ray diffraction. The surface acidities of the catalysts were measured from the chemisorption of pyridine at 150-degrees-C. The catalytic activities towards cumene cracking, o-xylene isomerization and isopropanol conversion were investigated. Cracking of cumene proceeds on the acid sites and follows first order kinetics. Mutual effect of the surface area and acidity is important in determining the activity of the catalyst in cracking of cumene. O-xylene isomerization is similar to cumene cracking, being structural sensitive reaction and takes place on the acid centres through first order kinetics. Conversion of isopropanol proceeds via two different pathes: dehydration on acid centres and dehydrogenation on MgO or possibly on the basic sites on the catalyst surface.