Role of adsorption in zeolite-catalyzed hydrocarbon cracking reaction

The activity for hydrocarbon cracking of zeolite catalysts depends on the t ype of zeolite and steam treatment. By comparing the activities of differen t zeolites under the condition where the catalyst did not undergo deactivat ion and the product distributions were identical, and presumably for the mo nomolecular mechanism, it was found that there were no differences in the c hemical properties of the active sites in the zeolites. The apparent differ ences in catalytic activities among zeolites could be attributed to differe nt concentrations of adsorbed alkane reactants, which is a consequence of t he different strength of interaction of the alkyl groups with the zeolite w alls. The latter may also be a significant contribute to the observed diffe rent strengths of interaction of alkyl amines with the Bronsted acid sites in zeolites.