Tungsten Catalyst Incorporating a Well‐Defined Tetracoordinated Aluminum Surface Ligand for Selective Metathesis of Propane, [(≡Si−O−Si≡)(≡Si−O−) 2 Al−O−W(≡C t Bu) (H) 2 ]
[1]
- University of Science and Technology 4700 King Abdullah Thuwal 23955-6900 Kingdom of Saudi Arabia
- Department of Chemistry Faculty of Science King Abdulaziz University (KAU) Jeddah 21589 Kingdom of Saudi Arabia
- King Abdullah University of Science and Technology(KAUST) Core Labs Thuwal 23955-6900 Kingdom of Saudi Arabia
- Department of Materials Science and Engineering University of California Davis CA 95616 USA
- Department of Chemical Engineering University of California Davis CA 95616 USA
- Institut Néel UPR 2940 CNRS Université Grenoble Alpes Grenoble F-38000 France
Abstract A well‐defined aluminium‐bound hydroxyl group on the surface of mesoporous SBA‐15, [(≡Si−O−Si≡) (≡Si−O) 2 Al−OH], 3 was obtained by reacting di‐isopropyl aluminium hydride with SBA‐15 treated at 700 °C. The resulting surface [(≡Si−O−Si≡) (≡Si−O) 2 Al (isobutyl) fragment undergoes β‐H elimination at 400 °C leading to [(≡Si−O−Si≡)(≡Si−O−) 2 Al−O) Al−H]. Further oxidation of this Al‐hydride with N 2 O leads to 3 . This acidic support was used to create a well‐defined surface organo‐tungsten fragment [(≡Si−O−Si≡)(≡Si−O−) 2 Al−O−W(≡C t Bu)(CH 2 tBu) 2 ] by reacting 3 with W(≡C‐ t Bu)(CH 2 ‐ t Bu) 3 . A further reaction with hydrogen under mild conditions afforded the tungsten carbyne bis‐hydride [(≡Si−O−Si≡)(≡Si−O−) 2 Al−O−W(H) 2 (≡C‐ t Bu)]. The performance of each of the W‐supported catalysts was assessed for propane metathesis in a flow reactor at 150 °C. [(≡Si−O−Si≡)(≡Si−O−) 2 Al−O−W(≡C t Bu)(H) 2 ] was found to be a single‐site catalyst, giving the highest turnover number (TON=800) and the highest reported selectivity for butane (45 %) vs . ethane (32 %) known for oxide‐supported tungsten complex catalysts (with the supports being silica, silica‐alumina, and alumina). The results demonstrate that modification of the oxide ligands on silica via the creation of Al Lewis acid center as an anchoring site for organometallic complexes opens up new catalytic properties, markedly enhancing the catalytic performance of supported organo‐tungsten species.
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- FG02-04ER15513
- OSTI ID:
- 1488689
- Journal Information:
- ChemCatChem, Journal Name: ChemCatChem Journal Issue: 1 Vol. 11; ISSN 1867-3880
- Publisher:
- Wiley Blackwell (John Wiley & Sons)Copyright Statement
- Country of Publication:
- Germany
- Language:
- English
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