Supported Copper(II) Arylhydrazone Complex on Synthesized Fe<sub>3</sub>O<sub>4</sub> Nanoparticles Boosted with TiO<sub>2</sub> for the Catalytic Oxidation of Alcohols
Mohamed Shaker S. Adam, M.M. Makhlouf, Amel Taha, Norah Alsadun, Mashael M. Alharbi, Ahmed Khalil
Abstract
For the modified progression of organo-oxidative reactions of alcohols, a monometallic copper(II) diarylhydrazone complex (CuONLCl) was constructed through the coordination of an arylhydrazone ligand (HONL) with a copper(II) ion. Its chemical structure was validated by alternative spectroscopic approaches. The heterogeneity of CuONLCl was constructed through successful surface covering of highly paramagnetic Fe 3 O 4 /TiO 2 nanoparticles (as CuONLCl@Fe 3 O 4 /TiO 2 ). The morphological and internal structure of the CuONLCl@Fe 3 O 4 /TiO 2 nanocomposite were analyzed with alternating microscopic and spectroscopic tools. The catalytic redox activity of CuONLCl (homogeneous) and CuONLCl@Fe 3 O 4 /TiO 2 (heterogeneous) was examined in the selective oxidative system of alcohols, e.g., benzyl alcohol (BZA), converting it to the corresponding carbonyl derivative (benzaldehyde, BZD) using H 2 O 2 . For optimization, the temperature, time, and solvent were adjusted to establish the highest redox activity of CuONLCl and CuONLCl@Fe 3 O 4 /TiO 2 . The mono-oxidative product (benzaldehyde) was contaminated with the overoxidative product, benzoic acid (BZC), and other side products. The homogeneous CuONLCl catalyst adjusted its catalytic oxidative action with lower reaction time for the optimized features compared to the heterogenized CuONLCl@Fe 3 O 4 /TiO 2 catalyst; however, CuONLCl@Fe 3 O 4 /TiO 2 displayed more selective progress in yielding the mono-oxidative product. Both Cu-catalysts showed an amazing reusability with 3 and 7 attempts for CuONLCl and CuONLCl@Fe 3 O 4 /TiO 2, respectively. The Fe 3 O 4 /TiO 2 nanoparticles exhibited enhanced reusability for CuONLCl@Fe 3 O 4 /TiO 2 compared to CuONCl.