Préparation et caractérisation des catalyseurs à base de ruthénium supporté sur la bentonite intercalée au chrome. Application à l'oxydation du cyclohexène.

Abstract

Our work deals with the intercalation of a montmorillonite clay (K10) with chromium. These clays were further used as support for ruthenium impregnation. Textural analysis showed that chromium intercalation increased samples surface area, which decreased upon ruthenium impregnation. This decrease may be attributed to pores obstruction by metal particles. XRD showed a delaminated structure. The FT-IR analysis, shows the presence of characteristic bands of the clay. Catalytic performances of our materials were evaluated in the reaction of liquid phase cyclohexene oxidation with tertiobutyl hydroperoxide TBHP. The results indicated that chromium and ruthenium oxides enhanced the catalytic activity and directed the selectivity towards cyclohexenone and cyclohexanone. A parallel between all results obtained at various conditions showed that the best conversion (45%) is obtained at 70°C upon 6 h reaction with 5% Ru/ Cr- (K10) (10 mmol), TBHP as oxidant using heptane as solvent.