Heterogeneous catalysis for thioanisole oxidation using hydrogen peroxide and Copper, Nickel and Zinc tungstates prepared by the polymeric precursor method

Abstract The oxidation of sulfides to sulfoxides and sulfones provides valuable sulfur-containing chemical compounds that are used in the pharmaceutical agrochemical industry. Although some tungsten catalytic systems have been applied to sulfide oxidation, the most desirable heterogeneous catalytic protocols have not been described. The copper, nickel and zinc tungstates powders obtained by the polymeric precursor method and the evaluation of their catalytic activity in thioanisole oxidation were investigated. Thioanisole was oxidized by hydrogen peroxide to sulfoxides and sulfones and the presence of catalyst accelerates the conversion. Of the three catalysts, copper tungstate was the most efficient in the conversion process followed by nickel tungstate and finally zinc tungstate. The copper tungstate has higher hydrogen consumption, indicating a higher oxygen content on the surface and the ability to increase surface mobility, which increases the conversion and selectivity of the process. The addition of 0.1 mL of hydrogen peroxide enhanced the conversion and increased the amount of sulfone produced. The ideal reaction time was 12 hours and the optimum temperature was 75 °C.

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Hydrogen peroxide decomposition on a two-component CuO-Cr2O3 catalyst

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19881636 ◽

1988 ◽

Vol 53 (8) ◽

pp. 1636-1646 ◽

Cited By ~ 8

Author(s):

Viliam Múčka ◽

Kamil Lang

Keyword(s):

Hydrogen Peroxide ◽

Catalytic Activity ◽

Extreme Values ◽

Catalytic Properties ◽

Active Components ◽

Catalytic Systems ◽

Heterogeneous Catalytic ◽

Peroxide Decomposition ◽

Two Component ◽

Catalytically Active

Some physical and catalytic properties of the two-component copper(II)oxide-chromium(III)oxide catalyst with different content of both components were studied using the decomposition of the aqueous solution of hydrogen peroxide as a testing reaction. It has been found that along to both basic components, the system under study contains also the spinel structure CuCr2O4, chromate washable by water and hexavalent ions of chromium unwashable by water. The soluble chromate is catalytically active. During the first period of the reaction the equilibrium is being established in both homogeneous and heterogeneous catalytic systems. The catalytic activity as well as the specific surface area of the washed solid is a non-monotonous function of its composition. It seems highly probable that the extreme values of both these quantities are not connected with the detected admixtures in the catalytic system. The system under study is very insensitive with regard to the applied doses of gamma radiation. Its catalytic properties are changed rather significantly after the thermal treatment and particularly after the partial reduction to low degree by hydrogen. The observed changes of the catalytic activity of the system under study are very probably in connection with the changes of the valence state of the catalytically active components of the catalyst.

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