SYNTHESIS, CHARACTERIZATION OF ZEOLITE Y-ENCAPSULATED COBALT SCHIFF BASE COMPLEXES AND THEIR CATALYTIC PERFORMANCE IN EPOXIDATION OF STYRENE

A series of zeolite Y encapsulated Co-X_2-salicyhexen complex catalysts, where salicyhexen represents salicylaldehyde-1,2-cyclohexanediamine and X represents H, OCH_3, Cl, Br or NO_2, were prepared by flexible ligand method and characterized by XRD, FTIR, UV-vis and thermal analysis. The results indicated that the complexes could form and be encapsulated in the supercages without affecting the zeolite framework structure. The effects of substituents on encapsulation and catalytic activity of the encapsulated complexes were also investigated. The prepared catalysts exhibitted high activity and stability in the epoxidation of styrene with molecular oxygen. Substitution of the aromatic hydrogen atom of the Schiff base ligand with electron withdrawing group decreased the amount of the complex encapsulated in the zeolite cavities, but could improve the catalytic activity of the encapsulated complex.