Pillared montmorillontes from unusual antiperspirant aqueous solutions: Characterization and catalytic tests

Abstract

Pillared clays (PILCs) based on montmorillonite clay were obtained using antiperspirant solution with different mmol of aluminum/g clay ratios at 80°C or at room temperature. The physico-chemical characterization of the intercalated clays and their pillared counterparts were performed by the following techniques: XRD, TGA/DTA, solid magic angle NMR, elemental analysis and nitrogen adsorption. The acidity of the pillared clays was estimated by the desorption of cyclohexylamaine and FTIR of pyridine desorption. The pillaring led to changes in the basal spacing of montmorillonite and stabilization of the smectite structure at higher temperature about 700°C. The total and micropore surface areas were improved with a creation of mesopores. The intercalated aluminum species were easily exchanged with decylamine, which was not the case of the aluminum oxide in the pillared clays after calciantion. The acidity of the pillared clays depended on the aluminum contents and to the outgassing temperatures, with strong Bronsted and Lewis acid sites up to 300°C. These acid sites played an important role in the hydro-isomerization of n-heptane. © 2012 Elsevier Inc. All rights reserved.