Preparation of W-modified FeMo catalyst and its applications in the selective oxidization of p-xylene to terephthalaldehyde

• W-modified FeMo catalyst was prepared by sol–gel method.
• FeMoW catalyst exhibited a higher activity stable.
• FeMoW exhibite higher oxidation performance than FeMo catalyst.
• Selective oxidation of PX on FeMoW catalyst is a Mars and van Krevelen type.

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 3 h with a catalyst dosage of 0.5 g, an air flow rate of 1000 mL min−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 50 h.