Accessing Realistic Models for the WO 3 –SiO 2 Industrial Catalyst through the Design of Organometallic Precursors

Y. Bouhoute (1) , D. Grekov (2) , K. Szeto (1) , N. Merle (1) , A. de Mallmann (1) , Fabrice Lefebvre (1) , G. Raffa (3) , Iker Del rosal (4) , Laurent Maron (4) , Régis M. Gauvin (2) , Laurent Delevoye (2) , M. Taoufik (1)

1 C2P2 - Laboratoire de Chimie, Catalyse, Polymères et Procédés, R 5265
2 UCCS - Unité de Catalyse et Chimie du Solide - UMR 8181
3 IRCELYON - Institut de recherches sur la catalyse et l'environnement de Lyon
4 LPCNO - Laboratoire de physique et chimie des nano-objets

In order to access realistic models to the industrial olefin metathesis catalyst WO3/SiO2, which is the bigrafted tungsten oxo alkylidene species [(≡SiO)2WO(═CHR)], we targeted the parent bis-alkyl oxo derivative [(≡SiO)2WOR2] prone to carbene formation. Thus, grafting of [WO(CH2EMe3)3Cl] (E = C, 1-Np; E = Si, 1-Ns) onto silica dehydroxylated at 200 °C was performed. While 1-Np affords the monopodal species [(≡SiO)WO(CH2CMe3)3] (2-Np), the neosilyl derivative 1-Ns reacts to yield the well-defined bipodal species [(≡SiO)2WO(CH2SiMe3)2] (2-Ns), via consecutive HCl and SiMe4 release. This was demonstrated by mass balance analysis, elemental analysis, IR, advanced solid-state NMR (1D and 2D 1H, 13C, 29Si, and 17O), and EXAFS. Furthermore, DFT calculations allowed understanding and rationalizing the experimental results regarding grafting selectivity. The material 2-Ns proved to lead to the most stable and efficient supported tungsten oxo catalyst for propene metathesis under dynamic conditions at 80 °C.

Domaines: Chimie

Y. Bouhoute, D. Grekov, K. Szeto, N. Merle, A. de Mallmann, et al.. Accessing Realistic Models for the WO 3 –SiO 2 Industrial Catalyst through the Design of Organometallic Precursors. ACS Catalysis, 2015, ACS Catalysis, 6 (1), pp.1-18. ⟨10.1021/acscatal.5b01744⟩. ⟨hal-01968734⟩