Nickel and molybdenum containing mesoporous catalysts for ethylene oligomerization and metathesis
Résumé
An original Ni-AlSiO2 mesoporous catalyst (Si/Al = 6.5, 2.0 wt% Ni) was prepared using a commercial
mesoporous non-ordered silica as a support. It exhibited notable catalytic behaviour for the oligomerization
of ethylene in both batch and flow mode. Thus, at 150 1C and 3.5 MPa, the catalyst was
highly active (up to 130 g of oligomers per gram of the catalyst per hour), selective (C4, C6, C8, and
C10 olefins, no cracking products) and stable (high conversion for 9 h on-stream). However, the
catalytic performances were slightly lower compared to those obtained with the catalyst prepared using
a mesostructured SBA-15 silica as a model support. When nickel-catalyzed oligomerization was coupled
with a metathesis reaction catalyzed by MoOx/(Al)SiO2 or MoOx/(Al)SBA-15, ethylene was efficiently
converted into propylene. To determine the physico-chemical properties of catalysts, various techniques
were used, such as powder X-ray diffraction, N2 sorption, 27Al MAS NMR, Raman spectroscopy and X-ray
photoelectron spectroscopy.