Heterogenized Acetylacetonates Palladium As Catalysts Of Hydrogen And Carbon Monoxide Reaction Oxidation
Heterogenized acetylacetonates palladium as catalysts of hydrogen and carbon monoxide reaction oxidation
V. K. Yatsimirsky, O. Yu. Boldyreva, L. P. Oleksenko, E. S. Yanovskaya
Shevchenko Kiev University Vladimirskaya Str. 64, 252033 Kiev,
Ukraine, Kiev, Ukrain
е-mail: yats@chem.univ.kiev.ua
It was earlier shown, that immobilized on the silica surface acetylacetone complexes of platinum show higher catalytic activity in hydrodgen and carbon monoxide oxidation , than platinum containing catalysts obtained by impregnation.
The results of catalytic activity investegation of fixed palladium acetylacetones with the different contents of metal (0.024 and 0.6 %) in H2 and CO oxidation are submitted.
It has been established, that heterogenized palladium complexes are more active in these reactions, than suported one Pd/SiO2 catalysts with the same metal content.
The total hydrogen conversion in a reaction mixture with oxygen excess (О2/ H2 = 25) occurs at temperature 800C on grafted catalysts with 0.024 % Pd content, while on suported Pd/SiO2 in curent conditions the transformation degree is equal to 27%.
The metal content reached leads to activity increasing. The similar regulariteis are found for carbon monoxide oxidation.
Not or any catalytic activity is found for acetylacetonate complex, which palladium content - 0.024 wt%. On immobillized Pd (acac) 2 with 0.6 % Pd at gaseues mixture with oxygen excess (О2/СО=20) a completely СО convertion has been observed at 140 0C, thus for Pd/SiO2 15 %, only. The hysteresis phenomena has been observed on plots of dependence of reaction speeds vs temperature for both reactions.
It has been revealed, that in hydrogen oxidation on heterogenized palladium complexs the catalysts surface shows "effect of a surface memory to
the earlier carried out reaction", that was earlier observed on platinum samples immobilized by Pt (acac)2.
The generaly shows, that immobillized on silica surface acetylacetone complexes can be perspective catalysts in small molecules oxidation at low temperatures.
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