SOLID ACID CATALYSTS FROM CLAYS - CUMENE SYNTHESIS BY BENZENE ALKYLATION WITH PROPENE CATALYZED BY CATION-EXCHANGED ALUMINUM PILLARED CLAYS

The alkylation of benzene with propene to produce cumene was carried o ut in batch (benzene/propene = 20/1) at T = 353 K and P = 0.55 MPa ove r aluminum pillared bentonite (APE) exchanged with K+, La3+ and Al3+ c ations. Both Al3+ and La3+ exchanged pillared clays were more active t han APE. As expected a complete deactivation was observed for the K+ e xchanged pillared clay. The large modifications of the catalytic activ ity cannot be explained by the observed slight textural differences. C ation exchange appeared to strongly modify the amount and nature of th e clays acid sites, The relative amount of Lewis and Bronsted acid sit es was evaluated by IR spectroscopy of adsorbed pyridine and analyzing the product distribution of the catalytic 1-butene isomerization. An apparent dependence of the reactivity from the amount of strong Lewis acid centers was clearly evident while a relationship with the amount of strong Bronsted acid sites was not found.