Etude : Etude de la réaction de l’oxydation du cyclohexène en présence de X% CeO2/TiO2.

Abstract

Our work was carried out in the LCSCO laboratory of Tlemcen for the preparation of mixed oxides catalysts X% CeO2 / TiO2 with different loading in ceria ie 1%, 2%, 3% and 5% .This preparation is done by the impregnation method.The various catalysts developed are characterized by several physicochemical techniques. An evaluation of the catalytic performances of the materials prepared is carried out in the oxidation reaction of cyclohexene in the liquid phase in the presence of tertbutyl hydroperoxide as oxidant. TiO2 peaks of anatase structure and that of ceria are identified by XRD. The IR analysis made it possible to highlight the characteristic bands of OH hydroxyl groups as well as Ti-OH bands. The textural analysis shows an increase in the specific surface area with the cerium content which is confirmed by the SEM by the particle distribution which becomes more and more homogeneous with the increase of the cerine content. Thermogravimetric analysis TGA revealed two mass losses due to evaporation of adsorbed water and dehydroxylation on the surface. The catalytic performance showed that the CeO2/TiO2 mixed oxide increases the catalytic activity of the catalysts and directs the reaction essentially towards the formation of the allylic oxidation products. Comparing the catalytic activity of the catalysts for the different cerine contents, the best conversion (40%) and the best cyclohexene-1-ol selectivity (86%) respectively are obtained with 5% CeO2 /TiO2 in the presence of TBHP as oxidant.