Tungsten-based mesoporous silicates W-MMM-E as heterogeneous catalysts for liquid-phase oxidations with aqueous H2O2

Nataliya Maksimchuk, Irina Ivanchikova, Olga Zalomaeva, Yurii Chesalov, Alexandr Shmakov, Vladimir Zaikovskii, Oxana Kholdeeva

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

Mesoporous tungsten-silicates, W-MMM-E, have been prepared following evaporation-induced self-assembly methodology and characterized by elemental analysis, XRD, N2 adsorption, STEM-HAADF (high angle annular dark field in scanning-TEM mode), DRS UV-vis, and Raman techniques. DRS UV-vis showed the presence of two types of tungsten oxo-species in W-MMM-E samples: isolated tetrahedrally and oligomeric octahedrally coordinated ones, with the ratio depending on the content of tungsten in the catalyst. Materials with lower W loading have a higher contribution from isolated species, regardless of the preparation method. W-MMM-E catalyzes selectively oxidize of a range of alkenes and organic sulfides, including bulky terpene or thianthrene molecules, using green aqueous H2O2. The selectivity of corresponding epoxides reached 85–99% in up to 80% alkene conversions, while sulfoxides formed with 84–90% selectivity in almost complete sulfide conversions and a 90–100% H2O2 utilization efficiency. The true heterogeneity of catalysis over W-MMM-E was proved by hot filtration tests. Leaching of inactive W species depended on the reaction conditions and initial W loading in the catalyst. After optimization of the catalyst system, it did not exceed 20 ppm and 3 ppm for epoxidation and sulfoxidation reactions, respectively. Elaborated catalysts could be easily retrieved by filtration and reused several times with maintenance of the catalytic behavior.

Original languageEnglish
Article number95
Number of pages20
JournalCatalysts
Volume8
Issue number3
DOIs
Publication statusPublished - 1 Mar 2018

Keywords

  • Alkene
  • Epoxidation
  • Evaporation-induced self-assembly
  • Heterogeneous catalysis
  • Hydrogen peroxide
  • Mesoporous tungsten-silicate
  • SELECTIVE OXIDATION
  • heterogeneous catalysis
  • hydrogen peroxide
  • COMPLEXES
  • evaporation-induced self-assembly
  • OXIDE CATALYSTS
  • EPOXIDATION
  • epoxidation
  • alkene
  • OLEFINS
  • mesoporous tungsten-silicate
  • HYDROGEN-PEROXIDE
  • EFFICIENT
  • NIOBIUM-SILICATES
  • METATHESIS
  • GREEN APPROACH

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