SURFACE ACIDITY-CRACKING ACTIVITY CORRELATION IN CHROMIUM PILLARED CLAYS

Chromium pillared montmorillonite and vermiculite catalysts have been prepared by intercalation with hydrolyzed metal ion solution. Pillarin g solutions with different chromium concentrations were prepared by va rying the base to chromium ratio. The catalysts were characterized by nitrogen adsorption, XRD, and IR studies. The nature of the acid sites was characterized by means of IR spectra data on pyridine adsorbed ch romium pillared catalysts. The acidity of the samples was determined b y butylamine titration. DSC has been used in the present study to prob e the nature of the surface acidity, its heterogeneity, acid strength, and density of acidic sites. Cumene cracking was carried out as a tes t reaction of Bronsted acidity. Both the density and strength of Brons ted acid sites were found to influence the cracking activity.