Catalysis of cyclohexane oxidation with heteropolyacid salts of SiO_2-supported cobalt substitution for phosphorus,molybdenum,and vanadium

Heteropolyacid salts of series supporter-type Dawson cobalt substitution for phosphorous,molybdenum,and vanadium were prepared with ultrasonic immersion method and the catalysts so obtained were characterized by using methods such as Fourier transform infrared spectroscopy,X-ray diffraction,and specific surface area determination.And these catalysts were used in the reaction of catalysis of cyclohexane selective oxidation to get cyclohexanol and cyclohexanon.The effect of different catalyst amount,reaction temperature,reaction time and the amount of H2O2 on reaction activity was investigated.The result showed that the silica gel processed with 3 mol/L HCl solution and ultrasonic immersion could make CoH7P2Mo15V3O62/SiO2 have better activity.The conversion of cyclohexane was 56.22% and the total yield of cyclohexanol and cyclohexanone was 17.19% under following conditions: the amount of cyclohexane was 0.1 mol,35%CoH7P2Mo15V3O62/SiO2 was 0.2 g,H2O2 with w(H2O2) being 50% was 13.6 g(0.2 mol),reaction time was 10 h,and the temperature was 75 ℃.