Nanosized TiO2 as a Recyclable Heterogeneous Catalyst for the Synthesis of Tetrahydrobenzo[b]pyran Derivatives

An electrochemical reduction method was used for the preparation of TiO 2 nanoparticles in which agglomeration with formation of undesired metal powders is prevented by the presence of ammonium stabilizers. These synthesized nanoparticles were characterized by UV–Visible, XRD, SEM–EDS and TEM analysis techniques. These synthesized nanoparticles of TiO 2 were tested as heterogeneous catalyst for the synthesis of tetrahydrobenzo[ b ]pyran derivative using three components reaction of aromatic aldehyde, dimedione and malononitrile by simply stirring at room temperature in a solvent free condition.