Activation Mechanism and Surface Intermediates during Olefin Metathesis by Supported MoOx/Al2O3 Catalysts
The activation of supported MoOx/Al2O3 catalysts and the resulting surface intermediates were examined with in situ DRIFTS during olefin metathesis reaction conditions, aided by C3D6-C3H6 isotopically labeled switching, C2H4-C4H8 titration, and temperature programmed reaction experiments. The studies shows that activation by propylene of the surface MoOx sites on Al2O3 initiates by forming surface isopropoxide species that subsequently dehydrogenate to acetone and surface Mo-OH. Desorption of acetone from the catalyst surface reduces the Mo+6 sites to Mo+4 sites, creating a vacancy for coordination of the next CH2=CHCH3 molecule. Oxidative addition from subsequent adsorption of propylene on the surface Mo+4 sites results in formation of surface Mo=CH2 and Mo=CHCH3 reactive intermediates, oxidizing the reduced surface molybdena sites back to Mo+6. This study demonstrates the activation mechanism and surface intermediates during olefin metathesis by supported MoOx/Al2O3 catalysts under reaction conditions.
- Research Organization:
- Lehigh Univ., Bethlehem, PA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
- Grant/Contract Number:
- SC0014510
- OSTI ID:
- 1510503
- Journal Information:
- Journal of Physical Chemistry. C, Journal Name: Journal of Physical Chemistry. C Journal Issue: XXX Vol. XXXX; ISSN 1932-7447
- Publisher:
- American Chemical SocietyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Similar Records
Identifying the Catalytic Active Site for Propylene Metathesis by Supported ReOx Catalysts
Studies of the mechanism of the olefin metathesis reaction and the process of active site formation on photoreduced molybdenum-silicate catalysts. I. Mechanism of formation of molybdenum-carbene intermediates