Synthesis, characterization and catalytic activity of a heterogeneous copper Schiff base complex supported on iron oxide nanoparticles for the oxidation of olefins

Initially, iron oxide nanoparticles (Fe3O4) were prepared and modified with tetraethoxysilane (TEOS). (3-Aminopropyl) trimethoxysilane (APTMS) and 2-hydroxybenzophenone were subsequently used to prepare Schiff base ligands on the surface of the nanoparticles. These modified nanoparticles were used in the synthesis of a copper Schiff base complex as a heterogeneous catalyst. The prepared catalyst was characterized using Fourier transform infrared spectrometry (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), inductively coupled plasma optical emission spectrometry (ICP-OES) and vibrating sample magnetometer (VSM) techniques. This catalyst was deployed in styrene, alpha-methyl styrene, cyclohexene and cyclooctene oxidation. In order to determine the optimum conditions, the following factors were investigated: time, solvent, amount of catalyst and oxidant. Under optimized conditions, the 100% conversion of styrene and alpha-methyl styrene with selectivities of benzaldehyde (71.4%) and acetophenone (67.7%) formation was obtained in a short reaction time (2 h).