Nióbia sintética modificada como catalisador na oxidação de corante orgânico: utilização de H2O2 e O2 atmosférico como oxidantes

Carvalho, Kele T. G.; Silva, Adilson C.; Oliveira, Luiz C.A.; Gonçalves, Maraísa; Magriotis, Zuy M.

doi:10.1590/s0100-40422009000600002

Cited by 14 publications

(5 citation statements)

References 6 publications

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“…The later catalysts have an appreciable number of defects on their surface, as demonstrated by Raman spectroscopy, which efficiently promote the hydrogen peroxide decomposition. On the other hand, the slower hydrogen peroxide suppression observed in the case of HY340-700, HY340-900, UP, UP-400, UP-500, UP-700 and UP-900 must be due the almost total absence of NbO 8 defects as well as the small amount of type NbO 7 defects thus allowing only the formation of η 1 dioxygen-type complexes (hydroperoxo or superoxo) [21,69].…”

Section: Go Set: After H2o2 Additionmentioning

confidence: 95%

New Insights on the Oxidation of Unsaturated Fatty Acid Methyl Esters Catalyzed by Niobium(V) Oxide. A Study of the Catalyst Surface Reactivity

et al. 2018

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Abstract:The catalytic properties of niobium(V) oxide (Nb 2 O 5 -CBMN) of different grades: amorphous, optical and ultra-pure, untreated or heat-treated at 400, 500, 700 and 900 • C were studied, before and after interaction with H 2 O 2 , by in situ Raman, FTIR-ATR and diffuse reflectance UV-Visible spectroscopy. The presence of different reaction sites for NbO 7 and NbO 8 type systems, which are directly related to surface defects present in different states of crystallization, were fully characterized. The reactivity of different catalysts obtained from niobium(V) oxide was investigated, using the oxidation of methyl linoleate in the presence of hydrogen peroxide as probe reaction. The reaction was followed by GC-MS, as well as by 1 H and 13 C NMR spectrometry and the dominant product was 9-oxo-nonanoic acid methyl ester. A reaction mechanism related to an auto-oxidation process must be occurring, leading initially to the formation of hydroperoxides, which decompose rapidly via Hock-type rearrangement, leading to the formation of aldehydes.

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Section: Go Set: After H2o2 Additionmentioning

confidence: 95%

New Insights on the Oxidation of Unsaturated Fatty Acid Methyl Esters Catalyzed by Niobium(V) Oxide. A Study of the Catalyst Surface Reactivity

et al. 2018

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“…The catalytic technology target in this work using hydrogen peroxide as a surface modifier is developing large active sites, which can be applied for the oxidation of larger molecules. For niobia (N b 2 O 5 ) bulk, it is possible to improve the oxidizer properties just with a simple modification of N b 2 O 5 surface by treatment the solid with hydrogen peroxide (H 2 O 2 ) [8][9][10][11]. The modified niobia shows high activity in the oxidation of cyclohexene [12], geraniol [13], and during the oxidation/dehydration of methanol to obtain dimethoxymethane [14].…”

Section: Introductionmentioning

confidence: 99%

Oxidation of geraniol using niobia modified with hydrogen peroxide

Lobo

Martínez

Rojas

et al. 2019

Rev.Fac.Ing.Univ.Antioquia

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Nb2O5 bulk and Nb2O5 modified with H2O2 were studied in the epoxidation of geraniol at 1 bar and room temperature. The structural and morphological properties for both catalysts were very similar, indicating that the peroxo-complex species were not formed. The order of the reaction was one respect to geraniol and close to zero respect to H2O2, these values fit well with the kinetic data obtained. The geraniol epoxidation is favored by the presence of peroxo groups, which is reached using an excess of H2O2. Moreover, the availability of the geraniol to adopt the three-membered-ring transition state was found as the best form for this type of compound.

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“…Mixed oxides containing niobium have been studied as catalysts and supports in several heterogeneous reactions [24,25]. Niobium oxides have a tendency to form structural defects and to present acid properties.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the Na/Nb2O5 system in the transesterification of soybean oil for biodiesel production

et al. 2016

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Biodiesel is considered an important substitute of diesel oil. Traditionally, it is obtained by the transesterification of vegetable oils with methanol or ethanol, catalyzed by NaOH or KOH. Heterogeneous catalysts have been studied with the aim at facilitating and diminishing costs with purification stages. In the present work, the Na/Nb2O5 system was evaluated on the reaction of soybean oil with ethanol. It was verified, by DRX and IR, that the niobia calcined at 500ºC and impregnated with sodium underwent greater structural alterations than that treated at 300°C. These modifications allowed the generation of basic properties on niobia surface (Hammett and CO2 adsorption /IR). This catalyst showed the highest conversion (30%) among the used materials. The method chosen for evaluating the catalysts yield was the 1H NMR spectroscopy.

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Nióbia sintética modificada como catalisador na oxidação de corante orgânico: utilização de H2O2 e O2 atmosférico como oxidantes

Cited by 14 publications

References 6 publications

New Insights on the Oxidation of Unsaturated Fatty Acid Methyl Esters Catalyzed by Niobium(V) Oxide. A Study of the Catalyst Surface Reactivity

New Insights on the Oxidation of Unsaturated Fatty Acid Methyl Esters Catalyzed by Niobium(V) Oxide. A Study of the Catalyst Surface Reactivity

Oxidation of geraniol using niobia modified with hydrogen peroxide

Evaluation of the Na/Nb2O5 system in the transesterification of soybean oil for biodiesel production

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