Synthesis, characterization and liquid phase oxidation of cyclohexane with hydrogen peroxide over oxovanadium(IV) Schiff-base tetradendate complex covalently anchored to multi-wall carbon nanotubes (MWNTs)

Abstract

The chemical modification of multi-wall carbon nanotubes (MWNTs) is an emerging area in material science. In the present study, hydroxyl functionalized oxovanadium(IV) Schiff-base; N,N'-bis(4-hydroxysalicylidene)-ethylene-1, 2-diamineoxovanadium(IV), [VO((OH)2-salen)]; has been covalently anchored on modified MWNTs. The new modified MWNTs ([VO((OH)2-salen)]-MWNTs]) have been characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron (XPS), UV-Vis, Diffuse reflectance (DRS), FT-IR spectroscopy and elemental analysis. The analytical data indicated a composition corresponding to the mononuclear complex of tetradentate Schiff-base ligand. The characterization of the data showed the absence of extraneous complex, retention of MWNTs and covalently anchored on modified MWNTs. Liquid-phase oxidation of cyclohexane with H2O2to a mixture of cyclohexanone, cyclohexanol and cyclohexane-1,2-diol in CH3CN have been reported using oxovanadium(IV) Schiff-base complex covalently anchored on modified MWNTs as catalysts. This catalyst is more selective toward cyclohexanol formation.