Catalytic Oxidation of Aniline to Azoxybenzene Over CuCr2O4 Spinel Nanoparticle Catalyst

Cationic surfactant cetyltrimethylammonium chloride-mediated hydrothermal preparation of CuCr2O4 spinel nanoparticles has been reported. This CuCr2O4 spinel nanoparticle catalyst has been characterized by XRD, XPS, SEM, TEM, TGA, and ICP-AES. Characterization results showed the formation of CuCr2O4 spinel nanoparticles with sizes between 25 and SO nm. It was found that the catalyst can selectively convert aniline to azoxybenzene with H2O2 as oxidant. The effect of different reaction parameters like reaction temperature, H2O2 to aniline molar ratio, reaction time, and so forth have been studied in detail. An aniline conversion of 78% with azoxybenzene selectivity of 92% can be achieved over this catalyst at 70 degrees C. The catalyst did not show any leaching up to five reuses, showing the true heterogeneity of the catalyst. However, significant H2O2 decomposition occurs on the catalyst necessitating its usage in five-fold excess.