Abstract
Ethylene carbonylation to propionic acid is a powerful route to the synthesis of oxygenates. Mo(CO)6 is a known homogenous catalyst for this reaction. When supported on HY zeolite, prepared by incipient wetness impregnation from pentane or by vapor deposition, turnover numbers dramatically increase to over 40,000 in 5 h of reaction, particularly for the supports with lower Si/Al ratios. Diffuse reflectance UV-visible spectra and thermogravimetric analysis indicate that lower Si/Al ratios promote more and stronger interactions between Mo(CO)6 and the support, leading to higher reactivity under liquid-phase reaction conditions. Although some leaching occurs under these conditions, the active catalyst is the supported Mo(CO)x/HY, and the recovered catalysts are still stable and active for ethylene carbonylation with turnover numbers exceeding 30,000 mol propionic acid/mol of Mo over 5 h at 190 °C. FTIR provides evidence for the formation and stabilization of under-coordinated carbonyl species during heat treatment, and such sub-carbonyls are known to be relevant in previously-established catalytic mechanisms.
Original language | English (US) |
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Pages (from-to) | 313-320 |
Number of pages | 8 |
Journal | Journal of Catalysis |
Volume | 338 |
DOIs | |
State | Published - Jun 1 2016 |
Funding
The authors acknowledge the financial support of The Dow Chemical Company . The CleanCat Core facility acknowledges funding from the Department of Energy ( DE-AC02-06CH11357 ) used for the purchase of the gas chromatography equipment and NH 3 -TPD. XRD characterization was done at the J.B. Cohen X-Ray Diffraction Facility supported by the MRSEC program of the National Science Foundation ( DMR-1121262 ) at Northwestern University. ICP-OES and Solid State NMR were performed at the Northwestern University Integrated Molecular Structure Education and Research Center with funding provided by NSF ( DMR-0521267 ). The authors thank Yuyang Wu at IMSERC for his technical assistance for solid state 27 Al NMR.
Keywords
- Carbonylation
- Ethylene
- Heterogeneous catalysis
- Impregnation
- Metal carbonyl
- Molybdenum
- Promotion
- Y-type zeolite
ASJC Scopus subject areas
- Catalysis
- Physical and Theoretical Chemistry