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Sio2-Included Cesium Polyoxotungstate Catalysts For Oxidation, W Trakarnpruk, W Kanjina
Sio2-Included Cesium Polyoxotungstate Catalysts For Oxidation, W Trakarnpruk, W Kanjina
Journal of Metals, Materials and Minerals
SiO2-included cesium polyoxotungstate catalysts were synthesized by a sol-gel method and characterizied by FTIR, XRD and N2 adsorption isotherms. XRD patterns prove that the cesium polyoxotungstate is uniformly dispersed in the silica network. The catalysts were used in oxidation of cyclohexane with H2O2. The products are cyclohexanol and cyclohexanone. The catalysts prepared by using a copolymer surfactant show higher surface area and exhibit higher activity. These catalysts are truly heterogeneous and can be reused at least 3 times.
Oxidation Of Cyclohexane And Ethylbenzene By Hydrogen Peroxide Over Co-Substituted Heteropolytungstate Catalyst, W Kanjina, W Trakarnpruk
Oxidation Of Cyclohexane And Ethylbenzene By Hydrogen Peroxide Over Co-Substituted Heteropolytungstate Catalyst, W Kanjina, W Trakarnpruk
Journal of Metals, Materials and Minerals
The tetrabutylammonium salt of Co-substituted heteropolytungstate, [(n-C4H9)4N]4 HPW11Co(H2O)O39.3H2O was synthesized and characterized. It was shown to be an active catalyst for the oxidation of cyclohexane and ethylbenzene. The oxidation reactions were performed using green oxidant hydrogen peroxide and acetonitrile as solvent. The major products of the oxidation of cyclohexane were cyclohexanone (K) and cyclohexanol (A). High selectivity towards K-A oil was achieved. At longer time cyclohexanol was converted to cyclohexanone. Ethylbenzene was also selectively oxidized to acetophenone. These oxidation reactions appear to be radical processes since they were totally inhibited in the presence of radical scavenger.