Synthesis of Hierarchical MeAPO-5 Molecular Sieve and Optimization of Its Catalytic Oxidation of Benzene to Phenol Based on Response Surface Method

Abstract

This study reports the hydrothermal synthesis of hierarchical aluminum phosphate molecular sieves doped with V, Cu, Fe, and Ni. The catalysts were characterized by XRD, SEM, EDS, XPS, NH₃-TPD, and N₂ adsorption-desorption from the perspectives of structure, morphology, acidity pore size, etc., which confirmed that the metals successfully infiltrated the molecular sieve skeleton. The synthesized D-MeAPO-5 molecular sieve was applied to the oxidation of benzene to the preparation of phenol. It was found that the catalytic effect of the D-VAPO-5 molecular sieve was superior to other catalysts. The conversion rate of benzene and selectivity of phenol were 27.0% and 80.4%, respectively, indicating that the activation ability of the C-H bond on the V-benzene ring was stronger. For optimal experimental design, the response surface method was carried out using D-VAPO-5 as the catalyst and phenol yield as the response value. In addition, a quadratic model was established for four influencing factors and phenol yield, and the significance of the factors was found to be as follows: reaction temperature>H₂O₂ dosage>catalyst dosage>reaction time.