Ultrasonic-assisted preparation of Co3O4 and Eu-doped Co3O4 nanocatalysts and their application for solvent-free synthesis of 2-amino-4H-benzochromenes under microwave irradiation

Co3O4 and Eu-doped Co3O4 nanocatalysts were synthesized through an ultrasonic-assisted solvothermal method and were characterized with X-ray diffraction (XRD), Fourier transform infrared (FT-IR), energy-dispersive X-ray (EDX), and field-emission scanning electron microscopy (FESEM) methods. Spinel cubic crystalline system for synthesized nanocatalysts was confirmed with XRD, whereas the spherical morphology of Co3O4 changed to nanorods after Eu3+ doping, which was affirmed with FESEM micrographs. Catalytic performance of the nanomaterials was examined through the synthesis of 2-amino-4H-benzochromenes using aromatic aldehydes, malononitrile, and beta-naphthol condensation under solvent-free conditions and microwave irradiation. Mild reaction conditions, short reaction times, simple setup, using an affordable catalyst, and high-quality products were some of the advantages of this procedure. The efficiency for Eu-doped nanocatalyst was achieved by about 96%.

Automated summary

Co3O4 and Eu-doped Co3O4 nanocatalysts were synthesized using ultrasonic-assisted solvothermal method and characterized using various methods; these nanocatalysts exhibited high efficiency in the synthesis of 2-amino-4H-benzochromenes under solvent-free conditions and microwave irradiation.