Activation of molecular oxygen in trifluoroacetic acid

The possibility of the formation of the H₂O₂^+· cation-radical was determined according to the data from nonempirical calculations for liquid trifluoroacetic acid, which forms a hydroperoxide radical after deprotonation. A catalytic cycle was obtained in which CF₃COOH serves as a catalyst in the oxidation of a substrate by dissolved molecular oxygen.     

Conversion of CO<Subscript>2</Subscript> in a trifluoroacetic acid

It is determined that the conversion of carbon dioxide in anhydrous trifluoroacetic acid (TFA) takes place at room temperature and atmospheric pressure, yielding a resinous product. Activation of CO₂ by the oxygen dissolved in a TFA is investigated.     

Photo-and thermogeneration of singlet oxygen by the metal ions deposited on Al2O3 and SiO2

The specifics of photo-and thermogeneration of singlet molecular oxygen by metal oxides deposited on silica gel and Al₂O₃ were studied. The deposited oxides were observed to generate equilibrium and superequilibrium concentrations of ¹Δ_gO₂. The V₂O₅/SiO₂ and MoO₃/SiO₂ systems were found to be most active in both types of generation. A common mechanism of photo-and thermogeneration was proposed.     

Oxidation of Sulfur Dioxide in Sodium and Calcium Fluorides

Kinetics and Catalysis - It was established that the oxidation reactions of sulfur dioxide occur in aqueous solutions of sodium fluoride and in suspensions of calcium fluoride at room temperature...     

The partial catalytic oxidation of toluene on vanadium and molybdenum oxides

The partial catalytic oxidation of toluene on pure and mixed vanadium and molybdenum oxides was studied over the temperature range 300–500°C. The main reaction products were maleic anhydride (MA), benzaldehyde (BA), and carbon oxides (CO _x ) depending on the catalyst composition and reactor temperature. The samples containing more than 50% vanadium were characterized by conversion and selectivity close to those of pure vanadium oxide V₂O₅. Reaction temperature was found to influence the amount of products formed, primarily the amounts of MA and BA. The role played by the generation of the singlet molecular oxygen form in the samples and its influence on the selectivity of the reaction is considered.     

Transformations of CO<Subscript>2</Subscript> in Two-Phase Systems C<Subscript>8</Subscript>F<Subscript>18</Subscript>–H<Subscript>2</Subscript>O and C<Subscript>6</Subscript>F<Subscript>6</Subscript>–H<Subscript>2</Subscript>O

The transformation of carbon dioxide in aqueous emulsions of perfluorons in the presence of oxygen in the air results in the formation of a mixture of oxalic acid and a minor set of organic compounds C₄–C₈. The maximum CO₂ consumption occurs in the emulsion with the C₈F₁₈: H₂O vol/vol ratio of 1: 0.42 at pH 2.4; the H₂C₂O₄ yield is 11 mol %.     

Oxidation of benzene and thiophene on a nanostructured vanadium-molybdenum mixed oxide

The catalytic oxidation of benzene and thiophene by air oxygen on a nanostructured vanadium-molybdenum mixed oxide with 50 mol % MoO₃ and 50 mol % V₂O₅ prepared by the solvothermal method is studied. It is shown that, in the temperature range 200–350°C, the catalyst efficiently oxidizes thiophene (with a degree of conversion of up to 40 mol %) and poorly oxidizes benzene. This enables to consider nanostructured molybdenum-vanadium oxides as promising for the low-temperature catalytic desulfurization of hydrocarbons. It is demonstrated that the reaction causes a change in the structure and morphology of the oxide system.     

Oxidation of dodecane on vanadium-molybdenum catalysts

The catalytic oxidation of dodecane with air oxygen on individual and mixed vanadium-molybdenum (1 ? x)V₂O₅ · xMoO₃ oxide is studied over a temperature range of 250 to 400°C. It is shown that oxidation of dodecane to organic acids at 250°C produces undecylic acid C₁₁H₂₆COOH and carbon oxides, as products of the subsequent oxidation of formic acid. The most effective catalyst is a mixed oxide containing 75 mol % MoO₃ and 25 mol % V₂O₅. At 275–300°C, this catalyst provides the maximum yield of acids and a relatively low fraction of complete-oxidation products. Above 250°C, a mixture of acids and carbon oxides is formed, the yield of which increases with the temperature up to 300°C. As the temperature is increased still further, the yield of acids decreases due to their subsequent oxidation. The catalytic oxidation is accompanied by changes in the phase composition, morphology, and degree of crystallinity of the mixed-oxide catalysts. A possible mechanism of the catalytic process is considered.     

Infrared spectroscopic studies on interactions in trifluoroacetic acid-sulfur dioxide systems

The method of frustrated multiple internal reflection (FMIR) infrared spectroscopy was used to study the nature of intermediates that formed upon oxidation of sulfur dioxide in trifluoroacetic acid (TFA) of various concentrations at 30°C. It was established that sulfur dioxide bound to a complex with TFA is oxidized by dissolved oxygen in systems that contain 99.9 and 55.5% trifluoroacetic acid.