Highly Efficient Ultrasound-assisted Green Epoxidation with H2O2 over a Structured Ni–CeO2–Al2O3–SiO2 Catalyst

Abstract

A study was performed to evaluate the application of a heterogeneous ceria-based structured catalyst (Ni–CeO₂–Al₂O₃–SiO₂) in the epoxidation of colza oil while reinforcing the process with ultrasonic irradiations. The prepared catalyst was characterized by XRD, FTIR, N₂ physisorption, SEM and DTA analyses. By optimizing reaction and sonication conditions, CzO conversion, epoxide yield and epoxidation reaction selectivity reached maximum values of 98, 96, and 97.96%, respectively. In addition to the iodine number and oxirane content, the formation of the oxirane group in ECzO synthesized under the optimized parameters was confirmed by the disappearance of the peaks corresponding to the C=C double bonds and by the appearance of a new peak at 825 cm^–1 in the FTIR spectrum of ECzO. The catalyst reuse study revealed that the activity of the NiCeX catalyst in the ultrasonic epoxidation of CzO decreased significantly only after 3 reaction cycles carried out under optimized parameters.