A novel copper(II) complex bearing salicylaldimine immobilized on SBA-15 and its catalytic performances in styrene oxidation by hydrogen peroxide

Salicylaldimine functionalized SBA-15 hybrid mesoporous material was synthesized by post-grafting of salicylaldehyde modified 3-aminopropyltriethoxysilane and followed by introducing Cu(II) ions into the hybrid material via a ligand exchange reaction. The prepared catalyst was characterized by means of XRD, N2 adsorption/desorption, SEM, FT-IR, UV–vis spectroscopy, EPR and XPS techniques as well as ICP-AES and elemental analysis measurements. The solid catalyst was evaluated in the oxidation of styrene with H2O2 as the oxidant under mild conditions, and the reaction parameters (the molar ratio of styrene/H2O2, amount of catalyst, temperatures, solvents, alkaline additive) were investigated and optimized for the oxidation of styrene. The optimal conversion (77.1%) and yield of styrene oxide (60.0%) were obtained at 80 °C using CH3CN as the solvent under basic conditions. Moreover, the covalently anchored Cu(II) salicylaldimine complex showed good recoverability and high stability against leaching of active copper(II) species.