Gas-phase oxidation of alcohols with dioxygen over Au/TiO2 catalyst: The role of reactive oxygen species

The activity of the (3% Au)/TiO2 catalyst with an average gold particle size of 3.6 ± 1.0 nm in the gas-phase oxidation of lower aliphatic alcohols (ethanol, propanol, isopropanol, and butanol) into the corresponding carbonyl compounds (acetaldehyde, propanal, acetone, and butanal) has been studied. A two-peak profile of the activity of the catalyst as a function of temperature has been observed in all of the reactions. The first peak falls within the temperature range from 120 to 130°C, while the complete conversion of the alcohols is achieved at 200–300°C. It is hypothesized that the low-temperature activity is due to the generation of a thermally unstable reactive oxygen species on the catalyst surface

Gas-phase oxidation of alcohols with O2 and N2O catalyzed by Au/TiO2: A comparative study

Gas-phase oxidation of alcohols (EtOH, PrOH, i-PrOH, BuOH) to their carbonyl derivatives was used as test reaction to elucidate the mechanism of a low-temperature catalytic activity of Au/TiO2. The reactions were carried out in the presence of molecular oxygen, nitrous oxide as well as in the absence of the gas-phase oxidants. The relative contribution of oxidative and non-oxidative dehydrogenation pathways was thus estimated. The presence of oxygen in the feed brought about to a double peak profile of catalytic activity as a function of temperature for all the alcohols. The low-temperature peak fells on 120–130 °C. In contrast, the use of N2O as an oxidant gave rise to usual profile of catalytic activity, which is similar to that of anaerobic dehydrogenation of alcohols. The results obtained allowed to suggest the mechanism of the alcohols oxidation. The low temperature peak is probably related to participation of active oxygen species, generated from O2 on the catalyst surface. Oxidation with N2O is interpreted by preliminary dehydrogenation of alcohols to corresponding carbonyl derivatives followed by H2 oxidation

Gas-phase oxidation of alcohols with O2 and N2O catalyzed by Au/TiO2: A comparative study

Gas-phase oxidation of alcohols (EtOH, PrOH, i-PrOH, BuOH) to their carbonyl derivatives was used as test reaction to elucidate the mechanism of a low-temperature catalytic activity of Au/TiO2. The reactions were carried out in the presence of molecular oxygen, nitrous oxide as well as in the absence of the gas-phase oxidants. The relative contribution of oxidative and non-oxidative dehydrogenation pathways was thus estimated. The presence of oxygen in the feed brought about to a double peak profile of catalytic activity as a function of temperature for all the alcohols. The low-temperature peak fells on 120–130 °C. In contrast, the use of N2O as an oxidant gave rise to usual profile of catalytic activity, which is similar to that of anaerobic dehydrogenation of alcohols. The results obtained allowed to suggest the mechanism of the alcohols oxidation. The low temperature peak is probably related to participation of active oxygen species, generated from O2 on the catalyst surface. Oxidation with N2O is interpreted by preliminary dehydrogenation of alcohols to corresponding carbonyl derivatives followed by H2 oxidation

Gas-phase oxidation of alcohols with dioxygen over Au/TiO2 catalyst: The role of reactive oxygen species

The activity of the (3% Au)/TiO2 catalyst with an average gold particle size of 3.6 ± 1.0 nm in the gas-phase oxidation of lower aliphatic alcohols (ethanol, propanol, isopropanol, and butanol) into the corresponding carbonyl compounds (acetaldehyde, propanal, acetone, and butanal) has been studied. A two-peak profile of the activity of the catalyst as a function of temperature has been observed in all of the reactions. The first peak falls within the temperature range from 120 to 130°C, while the complete conversion of the alcohols is achieved at 200–300°C. It is hypothesized that the low-temperature activity is due to the generation of a thermally unstable reactive oxygen species on the catalyst surface

Oxidative dehydrogenation of 1-butene to 1,3-butadiene over a multicomponent bismuth molybdate catalyst: influence of c3–c4 hydrocarbons

The influence of light hydrocarbons, such as n-butane, isobutane, propylene, cis- and trans-2-butenes, and isobutene on the oxidative dehydrogenation of 1-butene to 1,3-butadiene over BiMoKNiCoFePOx/SiO2 catalyst has been studied using a gas flow reactor. The inhibition effect of the listed hydrocarbons on the target reaction increased in the order of n-butane ~ isobutane < propylene < 2-butenes < isobutene. In addition, in contrast to 1-butene, isobutene has shown significant contribution to coke formation. It was suggested, that the coke formation and therefore the rate of the catalyst regeneration exercise a significant influence on the efficiency of 1-butene transformation into 1,3-butadiene in the concurrent presence of other hydrocarbons

Oxidative dehydrogenation of 1-butene to 1,3-butadiene over a multicomponent bismuth molybdate catalyst: influence of c3–c4 hydrocarbons

The influence of light hydrocarbons, such as n-butane, isobutane, propylene, cis- and trans-2-butenes, and isobutene on the oxidative dehydrogenation of 1-butene to 1,3-butadiene over BiMoKNiCoFePOx/SiO2 catalyst has been studied using a gas flow reactor. The inhibition effect of the listed hydrocarbons on the target reaction increased in the order of n-butane ~ isobutane < propylene < 2-butenes < isobutene. In addition, in contrast to 1-butene, isobutene has shown significant contribution to coke formation. It was suggested, that the coke formation and therefore the rate of the catalyst regeneration exercise a significant influence on the efficiency of 1-butene transformation into 1,3-butadiene in the concurrent presence of other hydrocarbons