Enhanced metathesis of ethylene and 2-butene on tungsten incorporated ordered mesoporous silicates
[Display omitted] •One-pot synthesized W-KIT-5, W-KIT-6, W-SBA-16 promote ethylene+2-butene metathesis.•Tetrahedrally and octahedrally-coordinated W species are active while bulk WO3 is inactive for metathesis.•Delayed addition of W source during synthesis enhances activity of W-KIT-6 catalyst.•XPS...
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Veröffentlicht in: | Applied catalysis. A, General General, 2016-11, Vol.528, p.142-149 |
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Format: | Artikel |
Sprache: | eng |
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•One-pot synthesized W-KIT-5, W-KIT-6, W-SBA-16 promote ethylene+2-butene metathesis.•Tetrahedrally and octahedrally-coordinated W species are active while bulk WO3 is inactive for metathesis.•Delayed addition of W source during synthesis enhances activity of W-KIT-6 catalyst.•XPS results confirm surface enrichment by W species when W addition is delayed.
Tungsten-incorporated 3D mesoporous silicates, W-KIT-6, W-KIT-5, and W-SBA-16 catalysts, outperform supported tungsten oxide catalysts (WO3/SiO2 and WO3/KIT-6) for the metathesis of ethylene and 2-butene to propene at 450°C. All catalysts exhibit steady activity and stability during 7h runs in a fixed-bed reactor. Furthermore, on all mesoporous catalysts, a maximum propylene yield was obtained at an optimum W loading at which the catalyst acidity is also maximum. Slightly delayed addition of the W source during the one-pot synthesis protocol markedly improves the propene yield on W-KIT-6 catalyst. XPS results conclusively show that this enhancement is due to preferential enrichment of active W species on the catalyst surface. Extended runs lasting five days reveal very little loss of activity even which is easily recovered by calcination in air. |
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ISSN: | 0926-860X 1873-3875 |
DOI: | 10.1016/j.apcata.2016.10.004 |