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Updated: Dec 12, 2025

Chemical Precipitation Method for the Synthesis of Nb2O5 Modified Bulk Nickel Catalysts with High Specific Surface Area
Published on: February 19, 2018
Niobium Oxides as Heterogeneous Catalysts for Biginelli Multicomponent Reaction
Letícia Gomes do Nascimento1, Isabela Milhomem Dias1, Guilherme Botelho Meireles de Souza1
1Institute of Chemistry, Federal University of Goiás, CEP 74690-900 Goiânia, Goiás, Brazil.
Abstract:
This study reports a simple, reusable, and recoverable niobium-based heterogeneous catalysts for Biginelli multicomponent reactions. Different methods of catalysts preparation were investigated. For this purpose, HY-340 (Nb2O5·nH2O) and Nb2O5 were chemically and/or thermally treated and investigated as catalysts for dihydropyrimidinones (DHPMs) production. The catalysts were characterized by scanning electron microscopy, high-resolution transmission electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, temperature-programmed desorption of NH3, adsorption/desorption of N2 at -196 °C, and thermogravimetric and differential thermal analysis. The characterization results showed that niobium oxides have the potential to be used as catalysts because of high crystallinity and large surface area. Among the tested catalysts, Nb2O5 chemically treated (Nb2O5/T) showed the best catalytic performance. In the absence of solvents, 94% yield of DHPMs was achieved. Also, Nb2O5/T can be reused three times without a significant yield decrease. Additionally, a feasible reaction pathway was suggested based on the Knoevenagel mechanism for DHPM synthesis using niobium-based catalysts.
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