PROPENE ALKYLATION OF LIQUID-PHASE BIPHENYL CATALYZED BY ALUMINA PILLARED CLAY CATALYSTS

The propene alkylation of liquid phase biphenyl has been catalyzed by several alumina pillared clays. The study included clays of various charge densities, charge localization and extent of layer stacking. For comparison purposes, the performance of an acid washed montmorillonite (K10) and two zeolites (H-mordenite and USY) were also investigated. Under liquid phase reaction conditions at 250-degrees-C and 140 psi propene, the reaction over pillared clays was under diffusion control. Thus, the activities and selectivities of the catalysts were very dependent on the particle size used. The catalytic activities were dependent on the pore structure and on the type of acid functionality. Typically, the catalysts with high Bronsted acidity (eg. alumina pillared beidellite) were more active than those exhibiting primarily Lewis acidity. The relationship between the pore structure of the catalyst and the distribution of monoalkylated products was also investigated. The more microporous catalysts (eg. alumina pillared montmorillonite) afforded higher yields of meta- and para-alkylated isomers than catalysts with little or no micropores (eg. K10 montmorillonite and delaminated Laponite). Coke formation occurred in the micropores and was related to the iron content of the clays.