Préparation, caractérisation et réactivité de l'acide 1-vanado-11-molybdo-phosphorique supporté sur des matériaux silicatés mésoporeux dans l'oxydation du propène

The H ₄PMo ₁₁VO ₄₀ heteropolyacid (HPA) was supported at 30 wt.% by the dry impregnation method on HMS, CMI-1 and SBA-15 mesoporous materials. The state of the HPA and those of the supports were examined by nitrogen physisorption, X-ray diffraction, (DR) FT-IR and X-ray photoelectron spectroscopies, thermal analysis (TG-ATD) and scanning electron microscopy (SEM). The effect of support on the catalytic behavior of H ₄PMo ₁₁VO ₄₀ was studied in the propene oxidation at 350 °C. It was shown that the presence of H ₄PMo ₁1VO ₄₀, modifies the textural properties of mesoporous materials (decrease of surface area) without destroying their structure. The interaction support-heteropolyacid leads to the formation of (SiOH ²⁺)(H ₃PMo ₁₁VO ₄₀ ^-) surface species more stable than H ₄PMo ₁₁VO ₄₀ species and that appear to be the active sites in the propene oxidation.