SURFACE-STRUCTURE AND ACIDITY OF ALUMINA-BORIA CATALYSTS

Both surface berate structures and acidities of alumina-boria catalyst s prepared by supporting B2O3 (boria) on an alumina support were inves tigated by using both B-11 magic angle spinning (MAS) NMR measurements and temperature-programmed desorption (TPD) of adsorbed pyridines, to gether with the catalytic properties of these alumina-boria materials for l-butene isomerization. The concentrations of tetrahedral oxygen-c oordinated berate (BO4) species as well as number of Bronsted acid sit es were found to increase with increasing boria content. The catalytic activity for l-butene isomerization was found to be caused by the str ong Bronsted acid sites generated from BO4 species on the surface of a lumina.