Aluminated mesoporous silica-pillared montmorillonite as acidic catalyst for catalytic cracking

Mesostructured aluminosilicate intercalates have been prepared by the post synthesis grafting of aluminum onto the mesostructured interlayer space silica framework of a silica-pillared clay (SPC) precursor derived from the natural montmorillonite. Elemental analyses, powder X-ray diffraction (XRD), scanning electron microscopy (SEM), N-2 adsorption-desorption isotherms, and Al-27 MAS NMR spectroscopy were used to characterize the products, which we designate Al-SPC. The Al-SPC derivatives exhibited basal spacings of 3.2-3.4 nm, BET surface areas of 444.8-806.7 m(2)/g, and pore sizes in the large micropore to small mesopore range (1.5-1.6 nm). The aluminum content was strongly correlated with the Si/Al stoichiometry of the post synthesis reaction mixture. Nearly all of the grafted aluminum was incorporated into tetrahedral sites in the interlayer silica framework. The alumination reagents afforded protonated Al-SPC derivatives with increased acidity in comparison to the initial silica-intercalated SPC precursor, as catalytic reactivity for cumene cracking. (C) 2011 Elsevier B.V. All rights reserved.