Optical and EPR spectral studies of structure of the adsorption centers of chromia-alumina catalysts

Abstract

Adsorption of n-hexane and benzene on sodium and demetallated synthetic faujasites at elevated temperatures was measured gravimetrically. Hexane was adsorbed with nearly equal heats of adsorption on sodium and demetallated Y zeolites; no preferential adsorption sites were detected. Heats of adsorption on NaY were less than on NaX because of reduced negative charge on the zeolite lattice. Benzene was also adsorbed on NaY nonspecifically but more strongly than was hexane. Both Bronsted acid sites in hydrogen Y and Lewis sites in decationized Y apparently serve as preferential sites for adsorption of benzene.