On the nature of oxygen particles in the low-temperature desorption from vanadium oxides

The nature of oxygen particles produced in low-temperature desorption from V₂O₅ and V₂O₅ · MoO₃ was studied. It was found that there was no low-temperature desorption from samples in the presence of a quartz trap cooled to −195°C, which was evidence of the absence of possible desorption of O₃ and the presence of ¹Δ_g O₂. Under these conditions, the latter was frozen completely, and ozone was not.     

Oxidation of dodecane on transition metal oxides

The catalytic oxidation of dodecane on individual and mixed vanadium and molybdenum oxides is studied. Products of the oxidation of alkane are studied qualitatively and quantitatively. The activities of the samples of the catalysts with various ratios of vanadium and molybdenum oxides are compared. One possible scheme for the activation of reagents on a catalyst is given.     

The oxidation of toluene on transition metal oxides

The oxidation of toluene on pure vanadium and molybdenum oxides was found to follow independent paths; it was benzene ring oxidation on V₂O₅ and side chain oxidation on MoO₃. On mixed xV₂O₅ · yMoO₃ oxides, the main reaction was the addition at the double bond preferably positioned meta rather than one-electron oxidation.     

Emission of active oxygen forms from a deposited bismuth oxide

The specific features of the emission of singlet oxygen from deposited bismuth oxide were examined. It was established how the rate of the emission of singlet oxygen depends on the concentration of deposited bismuth oxide. The largest amount of singlet oxygen was emitted from the sample with a crystalline structure. It was shown that only singlet molecular oxygen is emitted from deposited bismuth oxide.     

Superacids as catalysts of the oxidation of inorganic substrates

The oxidation of sulfur dioxide, nitrogen dioxide, carbon monoxide, etc., in anhydrous trifluoroacetic acid (TFA) at room temperature was observed. The oxidative ability of anhydrous TFA in reactions with inorganic substances was shown to be related to molecular oxygen dissolved in it. The dissolved molecular oxygen endowed TFA with the properties of a superacid with pK _a ? ?12. Mechanisms of active oxygen reactions with inorganic substrates were suggested.     

The selective catalytic oxidation of toluene

It was found for the first time that the selectivity of toluene transformations into benzaldehyde and benzoic acid decreased and into maleic anhydride and deep oxidation products increased as the ability of vanadium-containing catalysts of toluene oxidation to generate the singlet form of molecular oxygen grew. A scheme of the formation of the products of toluene oxidation with oxygen was suggested. Quinones were shown to be final rather than intermediate oxidation products. The selectivity of the reaction with respect to mild oxidation products in the presence of V₂O₅, MoO₃, and V₂O₅ · MoO₃ could be increased by changing the temperature of catalyst preparation from 400 to 500°C.     

Oxidative desulfurization of benzene fraction on transition metal oxides

It is established that molecular oxygen is able to oxidize thiophene selectively in a mixture with benzene on V₂O₅ · MoO₃. The introduction of thiophene inhibits the oxidation of benzene. It is shown that the conversion of thiophene during operation of the catalyst is reduced at first and then increases until it reaches its initial value.     

Oxidation of sulfites on vanadium-molybdenum oxides

The low temperature emission of ¹O₂ singlet oxygen from xV₂O₅ · yMoO₃ binary oxides is investigated by means of flash desorption. Conditions for the generation of ¹O₂ on their surfaces are determined, along with the correlation between the amount of ¹O₂ and the degree of NaHSO₃ conversion in the oxidation reaction. It is shown that on the surface of oxides there are oxygen species that upon decomposition produce ¹O₂ involved in the oxidation of HSO ₃ ^? .     

Chemical transformations of CO2 in trifluoroacetic acid solutions

It is established that a conversion reaction of carbon dioxide takes place at room temperature and atmospheric pressure in aqueous solutions of trifluoroacetic acid (TFA), which leads to the formation of oxalic acid and heavier polymerized products.     

The oxidation of dodecane on a vanadium-molybdenum catalyst

The catalytic oxidation of dodecane by air oxygen on a mixed vanadium-molybdenum oxide (V₂O₅ · MoO₃, 40 mol % MoO₃) was studied over the temperature range 300–350°C. The reaction at 300–330°C occurred on oxygen vacancies with the rupture of C-H bonds and formation of α-acid. Oxidation above 350°C occurred with the splitting of the C-C bond and formation of two and more acids. Singlet oxygen ¹O₂ generated in the oxidation of oxide catalyst lattice oxygen participated in the reaction. A possible mechanism of the process was considered.