Use of modified clay materials in toluene conversion

Clay materials, montmorillonite from Maghniya deposits (Algeria), were used as an acidic catalyst in toluene conversion. Toluene disproportionation reaction in gaseous phase was used. These clays were modified by ion exchange with uranyl ions UO22+. The surface acidity of catalysts was determined by the stepwise desorption technique (STD) of probe molecules using butylamine and ammonia. Thus, total acidity and distribution of the acidity strength were determined. The results show that materials presented an appreciable total acidity and catalytic activity in studied reaction. The acidity strength of catalysts due to UO22+ ions was kept at a temperature of 550 degrees C. A relationship was found between the catalytic activity and acidity strength generated by the introduction of uranyl ions in the clay structure. (C) 2010 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved.