Synthesis of vanadium oxides 5 wt.%VO 2 –M x O y by sol–gel process and application in cyclohexene epoxidation
Résumé
A series of Si02, Al203 and TiO2 mixed vanadium materials have been prepared from inorganic precursors via the sol gel process and subsequently dried, calcined and reduced at elevated temperatures. Structural characterization of these materials was carried out by X-ray diffraction (XRD), N2 adsorption at 77K, thermal analysis (TGA/DTA), UV-vis diffused reflectance spectroscopy (DR UV-vis) and scanning electron microscopy (SEM) with energy dispersive X-ray (EDX). Their catalytic activities in the epoxidation of cyclohexene with TBHP as oxidant were also examined. Results of XRD and DR UV-visible diffused revealed that V02 species are predominant in all samples and no formation of V205 was detected. Experimental results indicated that the V02 Si02 catalysts performed excellently for the epoxidation of cyclohexene by tertiobutyl hydroperoxide.