Аннотация

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.

Язык оригиналаанглийский
Номер статьи95
Число страниц20
ЖурналCatalysts
Том8
Номер выпуска3
DOI
СостояниеОпубликовано - 1 мар 2018

Fingerprint Подробные сведения о темах исследования «Tungsten-based mesoporous silicates W-MMM-E as heterogeneous catalysts for liquid-phase oxidations with aqueous H<sub>2</sub>O<sub>2</sub>». Вместе они формируют уникальный семантический отпечаток (fingerprint).

  • Цитировать