A Cis-dioxomolybdenum(VI) Schiff Base Nanoparticles and the Multiwalled Carbon Nanotube-Supported Compound: Heterogeneous Epoxidation of Olefins and Green Oxidation of Sulfides

Two cis-dioxomolybdenum(VI) complexes involving Schiff-base ligands bis (2,4-dihydroxy acetophenone)-1,2-cyclohexyl diimine (H2L1) and bis (2,4-dihydroxy acetophenone)-1,2-propyl diimine (H2L2) and their six-coordinated cis-dioxomolybdenum(VI) complexes [MoO2LX (X=1,2)] were obtained under ultrasonic irradiation. Then MoO2L1,2 complexes were covalently grafted to the multiwalled carbon nanotubes which is chemically modified (MoO2L1,2@MWCNT) and were characterized by elemental analyses and spectroscopic technique (IR, (1H,13C{1H}) NMR and UV–vis). The size distribution of the nanoparticles was measured by Scanning Electron Microscope (SEM) and Dynamic Light Scattering (DLS) and MoO2L1,2@MWCNT also were characterized by IR spectroscopy, Transmission Electron Microscopy (TEM) and X-ray diffraction (XRD). Heterogeneous selective oxidation of olefins with tert-butyl hydroperoxide (TBHP) catalyzed by MoO2L1 and MoO2L2 led to the formation of corresponding epoxides as the sole product with a yield of 75% and 100% respectively. Also green and heterogeneous oxidation of sulfides catalyzed by MoO2L1,2 and MoO2L1,2@MWCNT nanocatalysts are studied in one hour at room temperature. The MoO2L1,2@MWCNT catalysts represent higher selectivity and recycling towards sulfides which indicated that immobilization of catalysts on MWCNTs can enhance the stability and consequently reusability of them.

Keywords:

Cyclooctene Epoxidation , Green oxidation , Heterogeneous Catalysis , Molybdenum Schiff base , Nanocatalyst , Sulfides