Abstract: With Cu²⁺ as the metal center, 2,5-dihydroxyterephthalic acid as the organic ligand and phosphotungstic acid (H₃PW₁₂O₄₀, PTA for short) as the active component, a series of PTA/Cu-MOF-74 catalysts (x%PTA@Cu-MOF-74, x=0, 10, 20, 30, 40）with x% PTA loading (w) were synthesized by one-step hot solvent method. The catalysts were characterized by Fourier transform infrared spectroscopy, powder X-ray diffraction, scanning electron microscopy, nitrogen adsorption-desorption, and the catalytic activity of cyclohexene oxidation to adipic acid was tested. The results showed that the active component of PTA was successfully loaded into the Cu-MOF-74 skeleton, and the skeleton structure of MOF-74 remained intact. Under the reaction temperature of 80 ℃, reaction time of 6 h, the volume of cyclohexene of 1 mL, the volume of 30% H₂O₂ of 4.5 mL, and the dosage of 10%PTA@Cu-MOF-74 catalyst of 0.2 g, the yield of adipic acid was the best (61.96%), and the yield of adipic acid was 59.89% after the catalyst was reused for 4 times under the same test conditions, which was only 3.3% lower than that of using fresh catalyst.

Key words: MOF-74, phosphotungstic acid, catalytic oxidation, cyclohexene, adipic acid