Oxidation of sulfoxides to sulfones by hydrogen peroxide over Ti-containing zeolites

Moreau, P.; Hulea, Vasile; Gomez, Sylvie; Brunel, Daniel; Renzo, Francesco Di

doi:10.1016/s0926-860x(96)00400-0

Cited by 41 publications

(14 citation statements)

References 15 publications

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“…For sulfoxidation, there also remain questions about the basic mechanism of catalysis. Some reports of sulfoxidation over Ti‐substituted zeolites and polyoxometalates propose homolytic activation of H 2 O 2 with peroxygen transfer to thioether radical cation intermediates, while other reports suggest heterolytic activation pathways akin to classical epoxidation systems…”

Section: Resultsmentioning

confidence: 99%

Rate and Selectivity Control in Thioether and Alkene Oxidation with H₂O₂ over Phosphonate‐Modified Niobium(V)–Silica Catalysts

Thornburg

Notestein

2017

ChemCatChem

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Supported metal oxide catalysts are versatile materials for liquid‐phase oxidations, including alkene epoxidation and thioether sulfoxidation with H2O2. Periodic trends in H2O2 activation was recently demonstrated for alkene epoxidation, highlighting Nb‐SiO2 as a more active and selective catalyst than Ti‐SiO2. Three representative catalysts are studied consisting of NbV, TiIV, and ZrIV on silica, each made through a molecular precursor approach that yields highly dispersed oxide sites, for thioanisole oxidation by H2O2. Initial rates trend Nb>Ti≫Zr, as for epoxidation, and Nb outperforms Ti for a number of other thioethers. In contrast, selectivity to sulfoxide vs. sulfone trends Ti>Nb≫Zr at all conversions. Modifying the Nb‐SiO2 catalyst with phenylphosphonic acid does not completely remove sulfoxidation reactivity, as it did for photooxidation and epoxidation, and results in an unusual material active for sulfoxidation but neither epoxidation nor overoxidation to the sulfone.

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Section: Resultsmentioning

confidence: 99%

Rate and Selectivity Control in Thioether and Alkene Oxidation with H₂O₂ over Phosphonate‐Modified Niobium(V)–Silica Catalysts

Thornburg

Notestein

2017

ChemCatChem

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“…Overall, all substrates could be converted into corresponding sulfoxides or sulfones by adjusting the equivalent of H 2 O 2 , reaction time, and reaction temperature to obtain excellent selectivity (entries 1–7). Obviously, sulfoxides could be produced almost stoichiometrically, and moreover the corresponding sulfones were achieved with excellent selectivity under higher temperatures (50 or 60 °C) and more amounts of H 2 O 2 conditions, which makes the process a good substitute for sulfone production …”

Section: Resultsmentioning

confidence: 99%

“…Obviously,s ulfoxides could be produced almost stoichiometrically,and moreover the corresponding sulfones were achieved with excellent selectivity under higher temperatures (50 or 60 8C) and more amounts of H 2 O 2 conditions, which makes the process ag ood substitute for sulfone production. [29] Subsequently,t he recyclability of the catalystN b ÀOC@[TBA] [LA] was also examined under ah igherl oading condition (0.1 mol %, ca. 120 ppm).…”

Section: Kinetic Studiesmentioning

confidence: 99%

Ionic Liquid Stabilized Niobium Oxoclusters Catalyzing Oxidation of Sulfides with Exceptional Activity

Zhou

et al. 2019

Chemistry A European J

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We present here a new class of niobium oxoclusters that are stabilized effectively by carboxylate ionic liquids. These functionalized ILs are designated as [TBA][LA], [TBA][PA], and [TBA][HPA] in this work, in which TBA represents tetrabutylammonium and LA, PA, and HPA refer to lactate, propionate, 3‐hydroxypropionate anions, respectively. The as‐synthesized Nb oxoclusters have been characterized by use of elemental analysis, NMR, IR, XRD, TGA, HRTEM. It was found that [TBA][LA]‐stabilized Nb oxoclusters (Nb−OC@[TBA][LA]) are uniformly dispersed with an average particle size of 2–3 nm and afforded exceptionally high catalytic activity for the selective oxidation of various thioethers. The turnover number with Nb−OC@[TBA][LA] catalyst was over 56 000 at catalyst loading as low as 0.0033 mol % (1 ppm). Meantime, the catalyst also showed the high activity for the epoxidation of olefins and allylic alcohols by using only 0.065 mol % of catalyst (50 ppm). The characterization of 93Nb NMR spectra revealed that the Nb oxoclusters underwent structural transformation in the presence of H2O2 but regenerated to their initial state at the end of the reaction. In particular, the highly dispersed Nb oxoclusters can absorb a large amount of polar organic solvents and thus were swollen greatly, which exhibited “pseudo” liquid phase behavior, and enabled the substrate molecules to be highly accessible to the catalytic center of Nb oxocluster units.

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“…oxidation with DMSO) 70 and the reverse process, the oxidation of sulfides to sulfoxides and further to sulfones (Scheme 4). [71][72][73] Sulfoxides are only weak oxidizing agents, based on the redox potential of the R 2 SO/R 2 S system, but their reactivity changes considerably by coordination via the S or O atom. The scope of synthetic methods involving DMSO as a mild and selective oxidant is very broad.…”

Section: Dimethyl Sulfoxide the ''Sacrificial'' Solventmentioning

confidence: 99%

Reactions in “sacrificial” solvents

Mallát

Baiker

2011

Catal. Sci. Technol.

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The involvement of organic solvents in redox reactions and their influence on the efficiency and ''greenness'' of the desired chemical transformation are critically reviewed. Some representative examples are presented on the co-oxidation and co-reduction of widely used solvents (alcohols, ethers, nitriles, amides, sulfoxides, hydrocarbons, dense CO 2 ), and on the impact of these frequently hidden reactions. The transformation of the solvent may be limited to its unintended consumption leading to an increase in the E-factor, but it may also play a critical role in the reaction investigated and lead to false interpretation of reaction mechanisms. In fact, the approach of using a ''sacrificial'' solvent as a part of the oxidizing system may be an attractive-but surely not a green-alternative in synthetic chemistry. Finally, the crucial but often unrecognized role of the solvent in stabilizing or destabilizing catalytic metal nanoparticles is discussed. Surface redox reactions involving the solvent can be decisive for switching between heterogeneous and homogeneous catalytic pathways.

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Oxidation of sulfoxides to sulfones by hydrogen peroxide over Ti-containing zeolites

Cited by 41 publications

References 15 publications

Rate and Selectivity Control in Thioether and Alkene Oxidation with H₂O₂ over Phosphonate‐Modified Niobium(V)–Silica Catalysts

Rate and Selectivity Control in Thioether and Alkene Oxidation with H₂O₂ over Phosphonate‐Modified Niobium(V)–Silica Catalysts

Ionic Liquid Stabilized Niobium Oxoclusters Catalyzing Oxidation of Sulfides with Exceptional Activity

Reactions in “sacrificial” solvents

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Oxidation of sulfoxides to sulfones by hydrogen peroxide over Ti-containing zeolites

Cited by 41 publications

References 15 publications

Rate and Selectivity Control in Thioether and Alkene Oxidation with H2O2 over Phosphonate‐Modified Niobium(V)–Silica Catalysts

Rate and Selectivity Control in Thioether and Alkene Oxidation with H2O2 over Phosphonate‐Modified Niobium(V)–Silica Catalysts

Ionic Liquid Stabilized Niobium Oxoclusters Catalyzing Oxidation of Sulfides with Exceptional Activity

Reactions in “sacrificial” solvents

Contact Info

Product

Resources

About

Rate and Selectivity Control in Thioether and Alkene Oxidation with H₂O₂ over Phosphonate‐Modified Niobium(V)–Silica Catalysts

Rate and Selectivity Control in Thioether and Alkene Oxidation with H₂O₂ over Phosphonate‐Modified Niobium(V)–Silica Catalysts