Silica coated magnetic NiFe2O4 nanoparticle supported phosphomolybdic acid; synthesis, preparation and its application as a heterogeneous and recyclable catalyst for the one-pot synthesis of tri- and tetra-substituted imidazoles under solvent free conditions

Abstract

In this research, a magnetically-recoverable catalyst (NiFe₂O₄@SiO₂–H₃PMo₁₂O₄₀) was prepared by supporting phosphomolybdic acid (H₃PMo₁₂O₄₀) onto silica-coated NiFe₂O₄ nanoparticles. The prepared sample was characterized by FT-IR, TEM, SEM and VSM techniques and then the catalytic activity of this catalyst was investigated in the synthesis of tri- and tetra-substituted imidazole derivatives. More importantly, the catalyst was easily isolated from the reaction mixture by a magnetic bar and reused at least ten times without significant degradation in its activity.