Selective Oxidation of Cyclohexane Using Iron, Manganese, Nickel and Vanadium Doped ZrO2 in the Presence of Ozone

Abstract

In this study, 2.5 wt% of iron (Fe), manganese (Mn), nickel (Ni) and vanadium (V) doped zirconium oxide (ZrO₂) were used as catalysts for selective oxidation of cyclohexane in the presence of ozone. The catalysts were prepared using wet impregnation method. The catalysts were characterized using various spectroscopic and microscopic techniques. Cyclohexane (25 mL) was oxidized in an impinger glass reactor using 0.2 g of the catalysts at pH 3, 7 and 11. The reaction products were identified using gas chromatograph-mass spectrometry (GC–MS) and Fourier transform infrared spectroscopy (FT-IR). Fe/ZrO₂ outperformed all the catalysts with conversion of 36%. V/ZrO₂ was the least active catalyst at pH 3 with 14% cyclohexane conversion, whereas Mn/ZrO₂ was the least active catalyst at pH 7 and 11 with conversions of 21 and 28%, respectively. Cyclohexanol and cyclohexanone were only reaction products identified after 30 min at pH 3, 7 and 11. After 60 min only cyclohexanone was identified as reaction product. The results showed that Fe, Mn, Ni and V doped ZrO₂ coupled with ozone is the potential prospect for oxidation of cyclohexane.