Enhanced metathesis of ethylene and 2-butene on tungsten incorporated ordered mesoporous silicates

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 degrees C. All catalysts exhibit steady activity and stability during 7 h 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. (C) 2016 Elsevier B.V. All rights reserved.