Characterization of a bentonitic clay and its application as catalyst in the preparation of benzyltoluenes and oligotoluenes

The preparation of oligomeric toluenes catalyzed with a bentonitic clay, using thermal energy and ultrasound, was performed and evaluated. When ortho and para benzyltoluenes were studied, the oligomerization reaction was found to be dependent of the catalyst amount, reaction time, temperature and the presence of pyridine as competitive inhibitor. A proposal for the molecular structure calculation analysis at semiempirical AM1 level was proposed based on the regioselectivity and in the oligomerization pathway. Furthermore, a detailed study to characterize the clay was performed, thus several physicochemical properties of the clay were determinated by means of: Si-29 and Al-27 MAS-NMR, X-ray diffraction, X-ray fluorescence, scanning electron microscopy, IR spectrophotometry, thermal analysis (DTA, TG-DTG), and adsorption techniques (N-2-BET). (C) 2002 Elsevier Science B.V. All rights reserved.