An interpretation of proton acidity and its relevance to catalysis in low sodium content Y zeolites from studies of heats of immersion in methanol

The interrelationship of acidity and catalytic activity in reactions involving carbonium ions in zeolite-type catalysts has been studied. Heats of immersion of a range of HNaY zeolites in methanol at 293 K are presented. It has been shown that the interaction energy of the basic methanol molecule with the zeolite framework reflects the acid nature of the zeolite surface and this is correlated with catalytic results for the competitive ethylation of toluene and benzene, and also for cracking and isomerisation reactions. Assessment of acidity in decationated zeolite catalysts by this method should prove useful where other methods of measurement of acidity prove difficult.

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