A new highly active La2O3-CuO-MgO catalyst for the synthesis of cumyl peroxide by catalytic oxidation

Abstract

In this study, different magnesium, copper, lanthanide single metal, and composite multimetal oxide catalysts were prepared via the coprecipitation route for the aerobic oxidation of cumene into cumene hydroperoxide. All catalysts were characterized using several analytical techniques, including XRD, SEM, EDS, FT-IR, BET, CO₂-TPD, XPS, and TG-DTG. La₂O₃-CuO-MgO shows higher oxidation activity and yield than other catalysts. The results of XRD and SEM studies show that the copper and magnesium particles in the catalyst are smaller in size and have a distribution over a larger area due to the introduction of the lanthanum element. The CO₂-TPD results confirmed that the catalyst has more alkali density and alkali strength, which can excite active sites and prevent the decomposition of cumene hydroperoxide. XPS results show that due to the promotional effect of La₂O₃, there are more lattice and active oxygen species in the catalyst, which can effectively utilize the lattice defects under the strong interaction between metal oxides for rapid adsorption and activation, thus improving the oxidation performance. Besides, La₂O₃-CuO-MgO exhibits good stability and crystalline structure due to its high oxygen mobility inhibiting coking during the cycle stability test. Finally, the possible reaction pathway and promotional mechanism on La₂O₃-CuO-MgO in cumene oxidation are proposed. We expect this study to shed more light on the nature of the surface-active site(s) of La₂O₃-CuO-MgO catalyst for cumene oxidation and the development of heterogeneous catalysts with high activity in a wide range of applications.