Inhibitory effect of 2,6-di-tert-butylphenol groups in iron and manganese porphyrins on the catalytic activity in the oxidation of hydrocarbons by hydrogen peroxide

The catalytic properties of two-component catalyst nickel oxide-cadmium oxide with the proportions of the components covering the whole composition region 0-100% were examined by studying the decomposition of hydrogen peroxide in aqueous solution on it. In the range 0-25 mol.% CdO, cadmium oxide is found to affect infavourably the ability of nickel oxide to chemisorb oxygen. The amount of the chemisorbed oxygen increases several times on gamma irradiation of the samples. The effect of cadmium oxide on the catalytic activity of the system shows up in fresh samples only indirectly via the changed amount of the oxygen chemisorbed. In older samples the initial catalytic activity of the system is changed, which can be explained based on the concept of bivalent catalytic centres in terms of the co-action of the catalytic centres of the two oxides, which are in equilibrium. The irradiation of the system under study speeds up the processes leading to the establishing of this equilibrium which is thermally very stable, and results in a substantial increase of the catalytic activity of the samples investigated.

Download Full-text

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.

Download Full-text

Decoloration of Azo Dyes by Hydrogen Peroxide Catalyzed by Water-Soluble Manganese Porphyrins

Textile Research Journal ◽

10.1177/004051759906901212 ◽

1999 ◽

Vol 69 (12) ◽

pp. 956-960 ◽

Cited By ~ 18

Author(s):

J. Tokuda ◽

R. Ohura ◽

T. Iwasaki ◽

Y. Takeuchi ◽

A. Kashiwada ◽

...

Keyword(s):

Hydrogen Peroxide ◽

Azo Dyes ◽

Water Soluble ◽

Manganese Porphyrins

Download Full-text

Hormetic Concentrations of Hydrogen Peroxide but Not Ethanol Induce Cross-Adaptation to Different Stresses in Budding Yeast

International Journal of Microbiology ◽

10.1155/2014/485792 ◽

2014 ◽

Vol 2014 ◽

pp. 1-5 ◽

Cited By ~ 18

Author(s):

Halyna M. Semchyshyn

Keyword(s):

Hydrogen Peroxide ◽

Dose Response ◽

Budding Yeast ◽

Regulatory Protein ◽

Colony Growth ◽

Inhibitory Effect ◽

Cross Resistance ◽

Mild Stress ◽

Low Concentrations ◽

Cross Adaptation

The biphasic-dose response of microorganisms to hydrogen peroxide is a phenomenon of particular interest in hormesis research. In different animal models, the dose-response curve for ethanol is also nonlinear showing an inhibitory effect at high doses but a stimulatory effect at low doses. In this study, we observed the hormetic-dose response to ethanol in budding yeastS. cerevisiae. Cross-protection is a phenomenon in which exposure to mild stress results in the acquisition of cellular resistance to lethal stress induced by different factors. Since both hydrogen peroxide and ethanol at low concentrations were found to stimulate yeast colony growth, we evaluated the role of one substance in cell cross-adaptation to the other substance as well as some weak organic acid preservatives. This study demonstrates that, unlike ethanol, hydrogen peroxide at hormetic concentrations causes cross-resistance ofS. cerevisiaeto different stresses. The regulatory protein Yap1 plays an important role in the hormetic effects by low concentrations of either hydrogen peroxide or ethanol, and it is involved in the yeast cross-adaptation by low sublethal doses of hydrogen peroxide.

Download Full-text