Co(II) Schiff base complexes encapsulated in the zeolite-Y as efficient and reusable nanocatalysts for epoxidation of styrene in mild conditions

However, most of such epoxidation reactions are still using homogeneous catalysts. From the sustainable and green chemistry point of view, heterogeneous catalysts would be interesting since they offer the benefits of possible catalyst recycling, easy catalyst separation and sometimes high selectivity and activity [1]. In this respect, encapsulation of transition metal complex in zeolite-Y gained much interest in the last decade [2]. Cobalt (II) macrocyclic complexes synthesized inside the nanocavity of zeolite-Y were characterized by FT-IR, DRS, AAS, XRD, molar conductance, magnetic moment data, thermal and elemental analysis (Scheme 1).These complexes (neat and encapsulated) were used for epoxidation of styrene with O2 as oxidant in different solvents. Reaction parameters including temperature, catalyst amount and solvent were screened by reaction time. The supported Co[L2]2+-Y exhibited a moderate 62.8 % selectivity for epoxidation with 86.2 % conversion. The recycling experiment results indicated that the catalysts were highly stable and maintained activity and selectivity even after being used for five cycles