Copper(II)imida-salen complexes encapsulated into NaY zeolite for oxidations reactions

Abstract

Oxidation of phenol, cychohexanol and hydroquinone has been screened in the presence of copper(II) complexes with Schiff base Salen ligand, 1,5-bis{[(1E)-(2-hydroxyphenyl)methylene]amino}-1H-imidazole-4-carbonitrile, and encapsulated in the zeolite NaY using two different methods (A and B). The new heterogeneous catalysts were characterized by SEM, XRD, FTIR, EPR, Raman and chemical analysis. The structure of the copper(II) complexes were proposed by theoretical studies (DFT). The catalytic activities of the encapsulated copper(II) complexes in NaY were compared with the homogeneous counterpart. The results show higher or similar substrate conversion when compared with the free complex in all the reactions tested. After their use in catalytic reaction, these catalysts were found to be reusable without loss of activity.