Olefin metathesis is used on a large-scale processes such as in Shell’s Higher Olefins Process (SHOP), Phillips’ neohexene process, and ABB Lummus’ Olefins Conversion Technology (OCT).1 The supported Mo and W oxides used as catalysts in these gas-phase applications require elevated reaction temperatures. For example, the SHOP metathesis catalyst, MoO3/g-Al2O3, operates at 100-200 °C, while the WO3/SiO2 catalyst used for OCT and the neohexene process requires at least 400 °C. Although different preparation techniques for these catalysts have been investigated, the final calcination step leads inevitably to a mixture of different surface species being difficult to distinguish. Despite the complexity of the rather simple MO3/SiO2 (M = Mo, W) catalyst, the active site, proposed a couple of decades ago, consisting of a bipodal isolated metal(VI) center bearing an oxo ligand and a carbene fragment (scheme 1) is still well-accepted.2 Surface organometallic chemistry can lead to more specifically tailored heterogeneous catalysts with known structure-activity relationships with improved life times and higher number of active sites. By judicious choice of the precursor and the treatment of the support, the podality, oxidation state and coordination environment around the metal center can be controlled. Following our previous studies, highly active olefin metathesis catalysts, in particularly based on isolated oxo centers have successfully been prepared by this approach (Scheme 2).3 (1) Mol, J. C. J. Mol. Catal. A: Chem. 2004, 213, 39. (2) Grunert, W.; Feldhaus, R.; Anders, K.; Shpiro, E. S.; Minachev, K. M. J. Catal. 1989, 120, 444. (3) i) Mazoyer, E.; Merle, N.; de Mallmann, A.; Basset, J. M.; Berrier, E.; Delevoye, L.; Paul, J. F.; Nicholas, C. P.; Gauvin, R. M.; Taoufik, M. Chem. Commun. 2010, 46, 8944-8946. ii) Merle, N.; Girard, G.; Popoff, N.; De Mallmann, A.; Bouhoute, Y.; Trebosc, J.; Berrier, E.; Paul, J. F.; Nicholas, C. P.; Del Rosal, I.; Maron, L.; Gauvin, R. M.; Delevoye, L.; Taoufik, M. Inorg. Chem. 2013, 52, 10119. iii) Bouhoute, Y.; Garron, A.; Grekov, D.; Merle, N.; Szeto, K. C.; De Mallmann, A.; Del Rosal, I.; Maron, L.; Girard, G.; Gauvin, R. M.; Delevoye, L.; Taoufik, M. ACS Catal. 2014, 4, 4232-4241.

Well-defined group VI oxo derivatives supported on silica by SOMC: Model of industrial olefin metathesis catalyst

251st National Meeting (2016)

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