Chlorinated alumina. Acidic properties and catalytic activity towards n-butane isomerization

Abstract

γ-Al₂O₃ has been chlorinated by CCl₄ at 573 K in order to increase its acidity. Different physical methods, including infrared spectroscopy, thermogravimetry and thermodesorption of pyridine, have been used to calculate the actual number of acidic sites, according to their strength. Comparison with samples treated with HCl or AlCl₃ leads to the conclusion that stronger Lewis sites are in the form of grafted AlCl₃. n-Butane isomerization has been performed on such solids. Reaction occurs without the presence of metal and the higher the acidity the higher the activity and selectivity.