Preparation of Bifunctional Zeolite Catalysts by SSIE

These results seemed to indicate that the acid and hydrogenation functions were not properly balanced and larger palladium particles had formed at the 

to reduce the density of Bronsted acid sites in the bifunctional zeolite catalysts, introduction of both Ca + and Pd was carried out, and this was done either simultaneously (method A) or successively (method B). Best results were obtained by method B. As an example. Fig. 62 shows the conversion of ethylbenzene and the yields of ethylcyclohexane, xylenes, dimethylcyclohexanes, alkanes, benzene and diethylbenzenes over a Pd,Ca,H-ZSM-5 catalyst prepared by a two-step solid-state ion exchange. In a first step, CaCl2 was incorporated via SSIE, followed by a second step, viz., SSIE of PdCl2 into Ca,H-ZSM-5 obtained in the first step. 

Dealkylation (or hydrogenolysis) of ethylbenzene was largely and disproportionation almost completely suppressed. Similarly, dehydrogenation of cyclohexane over Pd,Ca,H-ZSM-5 prepared via successive SSIE proceeded with high selectivity and very low catalyst deactivation (cf. Fig. 63). 

It is evident from Fig. 64 that, in contrast to case A of simultaneous SSIE, the two-step solid-state reaction (case B) and subsequent reduction resulted in a shift to smaller particles and narrower particle size distributions with increas- 

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