Preparation of W-modified Fe[sbnd]Mo catalyst and its applications in the selective oxidization of p-xylene to terephthalaldehyde

Abstract

FeMoW catalysts were prepared by a sol–gel method and used in the catalytic selective oxidation of p-xylene (PX) to prepare terephthalaldehyde (TPAL). The results showed that Mo, Fe, and W exist as oxides in the composite, and the FeMo and FeMoW catalysts were stable between 400 and 600°C. The FeMoW catalyst was more easily reduced to a lower valence state, and the lattice oxygen of the FeMoW catalyst was higher than that of the FeMo catalyst. These phenomena demonstrated a higher oxidation performance than the FeMo catalyst. The FeMoW catalyst calcined at 550°C was reacted at 500°C for 3h with a catalyst dosage of 0.5g, an air flow rate of 1000mLmin−1, and a PX liquid hourly space velocity of 1.2mLgcat-1h-1, the conversion of PX, the selectivity and the yield of TPAL was 99.5%, 74.0%, and 73.6%, respectively, and the FeMoW catalyst was stable after 50h.