Construction of novel Mg Fe2O4/MgO composite: A high performer Photocatalyst for the cyclization of 1,3,4-oxadiazoles under Sunlight Irradiation

Abstract

Magnesium ferrite nanoparticles were synthesized by a solid-state reaction of Mg (NO₃)₂.6H₂O, Fe (NO₃)₃.9H₂O, NH₄OH, and an optimum amount of distilled water and then calcined at high temperatures. In order to enhance the catalytic properties of magnesium ferrite particles, magnesium oxide as support was added, and thus catalysts MgFe₂O₄/MgO was successfully obtained in alkaline medium. The structure of the synthesized MgFe₂O₄/MgO catalyst was identified using FT-IR, XRD, SEM, BET, XPS, ICP-OES, EDX, and TGA techniques. Thus, MgFe₂O₄/MgO catalyst is employed as heterogeneous photocatalyst for the synthesis of substituted 1,3,4-oxadiazole derivatives using 2-amino-5-chloroanthanilic acid hydrazide and aldehydes as substrates in semi-aqueous conditions. The material had better photoactivity than bare MgO. It could make a wide range of oxadiazoles in as little as 30 min, and it was stable and could be recycled again and again. The best conditions for making model compounds (3b) with a 97 % yield were 30 min, 10 mg catalyst, and 100 mW cm⁻² light for photocatalysis and 80 °C for thermocatalysis. The photocatalytic technique improved yield and reaction time under optimal conditions. Photocatalytic synthesis saves ≈70 % more energy than thermal method. Even after four runs on recycled materials, the MgFe₂O₄/MgO photocatalyst showed outstanding stability. Nevertheless, the recycled catalyst showed unchanged behavior after repeated characterization, confirming the material's integrity. Moreover, the substrate condensation is due to light interaction ability, which is able to photocatalyze the cyclization to the final 1,3,4-oxadiazoles, demonstrating the optimal performance of this photocatalytic MgFe₂O₄/MgO material.