Surface characteristics and cracking activity of zirconium pillared clays

Zirconium pillared montmorillonite and vermiculite catalysts have been prep ared using four different methods by intercalation with zirconium oxychlori de solution. The surface characteristics of the catalysts have been charact erized using nitrogen adsorption, XRD and IR studies. The nature of acid si te is identified on the basis of IR spectral data of pyridine and ammonia a dsorbed zirconium pillared catalysts. The acidity of the samples was determ ined by butylamine titration as well as by thermal desorption of pyridine a nd ammonia. Differential scanning calorimetric technique has also been used to probe the nature of acidic sites, their heterogeneity, acid strength an d density. Cumene cracking has been carried out as a test reaction of Brons ted acidity. The product selectivity is towards benzene. The cracking activ ity has been correlated with the density of Bronsted acid sites.