Synthesis of Fe, Co, and Mn substituted AlPO-5 molecular sieves and their catalytic activities in the selective oxidation of cyclohexane

摘要

Fe, Co, and Mn substituted AIPO-5 molecular sieves, including FeAPO-5, CoAPO-5, MnAPO-5, FeCoAPO-5, FeMnAPO-5, and CoM-nAPO-5 were synthesized by hydrothermal method and characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), nitrogen adsorption, and Fourier transform infrared (FT-IR) spectroscopy. The lattice expansions were observed with Fe, Co, and/or Mn substitution of Al atom in AIPO-5. The selective oxidation of cyclohexane to cyclohexanone and cyclohexanol (K/A oil) with molecular oxygen was studied over these catalysts at the reaction temperature of 403 K. The higher activities of the multi-metal substituted AIPO-5, compared to that of single metal substituted AIPO-5, were observed. The underlying reason for the superior activity of the multi-metal substituted AIPO-5 was analyzed.