Representation of an Efficient Method for Improving Catalytic Activity of Zeolite Y as a Heterogeneous Catalyst in Synthesis of Some Schiff Bases Based on Azo Compounds

M/Y zeolites (M = Cu (II), Ni (II) and Co (II)) were synthesized by microwave solid state and aqueous solution ion-exchange methods. Then, these compounds were prepared in nano scale. Copper(II) nitrate, cobalt(II) nitrate, zeolite Y, nano-sized zeolite Y and all of nano-sized M/Y zeolites were used as acidic catalysts for the synthesis of 2-[(5-Chloro- 2-hydroxy-phenylimino)-methyl]-4-(4-nitro-phenylazo)-phenol (2a) as a model reaction and homogenous catalysts were compared to heterogeneous catalysts. The solid state ion-exchanged zeolites showed higher activity in comparison to aqueous solution ion-exchanged zeolites and Co was selected as the best metal. The amount of catalyst was optimized and nano-sized solid state ion-exchanged Co/Y zeolite was reused for three times. Finally, other derivatives of Schiff bases based on azo were synthesized by nano-sized solid state ion-exchanged Co/Y zeolite and yields were reported. The structure of 2a-j was confirmed using elemental analysis, 1H-NMR and FT-IR spectroscopy.