Mechanism of n-butane hydrogenolysis promoted by Ta-hydrides supported on silica

Handle URI:
http://hdl.handle.net/10754/563592
Title:
Mechanism of n-butane hydrogenolysis promoted by Ta-hydrides supported on silica
Authors:
Pasha, Farhan Ahmad; Cavallo, Luigi ( 0000-0002-1398-338X ) ; Basset, Jean-Marie ( 0000-0003-3166-8882 )
Abstract:
The mechanism of hydrogenolysis of alkanes, promoted by Ta-hydrides supported on silica via 2 ≡ Si-O- bonds, has been studied with a density functional theory (DFT) approach. Our study suggests that the initial monohydride (≡ Si-O-)2Ta(III)H is rapidly trapped by molecular hydrogen to form the more stable tris-hydride (≡ Si-O-) 2Ta(V)H3. Loading of n-butane to the Ta-center occurs through C-H activation concerted with elimination of molecular hydrogen (σ-bond metathesis). Once the Ta-alkyl species is formed, the C-C activation step corresponds to a β-alkyl transfer to the metal with elimination of an olefin. According to these calculations, an α-alkyl transfer to the metal to form a Ta-carbene species is of higher energy. The olefins formed during the C-C activation step can be rapidly hydrogenated by both mono- and tris-Ta-hydride species, making the overall process of alkane cracking thermodynamically favored. © 2014 American Chemical Society.
KAUST Department:
KAUST Catalysis Center (KCC); Physical Sciences and Engineering (PSE) Division; Chemical Science Program
Publisher:
American Chemical Society (ACS)
Journal:
ACS Catalysis
Issue Date:
6-Jun-2014
DOI:
10.1021/cs5001703
Type:
Article
ISSN:
21555435
Sponsors:
This work was supported by King Abdullah University of Science and Technology (KAUST) Saudi Arabia.
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division; Chemical Science Program; KAUST Catalysis Center (KCC)

Full metadata record

DC FieldValue Language
dc.contributor.authorPasha, Farhan Ahmaden
dc.contributor.authorCavallo, Luigien
dc.contributor.authorBasset, Jean-Marieen
dc.date.accessioned2015-08-03T11:55:13Zen
dc.date.available2015-08-03T11:55:13Zen
dc.date.issued2014-06-06en
dc.identifier.issn21555435en
dc.identifier.doi10.1021/cs5001703en
dc.identifier.urihttp://hdl.handle.net/10754/563592en
dc.description.abstractThe mechanism of hydrogenolysis of alkanes, promoted by Ta-hydrides supported on silica via 2 ≡ Si-O- bonds, has been studied with a density functional theory (DFT) approach. Our study suggests that the initial monohydride (≡ Si-O-)2Ta(III)H is rapidly trapped by molecular hydrogen to form the more stable tris-hydride (≡ Si-O-) 2Ta(V)H3. Loading of n-butane to the Ta-center occurs through C-H activation concerted with elimination of molecular hydrogen (σ-bond metathesis). Once the Ta-alkyl species is formed, the C-C activation step corresponds to a β-alkyl transfer to the metal with elimination of an olefin. According to these calculations, an α-alkyl transfer to the metal to form a Ta-carbene species is of higher energy. The olefins formed during the C-C activation step can be rapidly hydrogenated by both mono- and tris-Ta-hydride species, making the overall process of alkane cracking thermodynamically favored. © 2014 American Chemical Society.en
dc.description.sponsorshipThis work was supported by King Abdullah University of Science and Technology (KAUST) Saudi Arabia.en
dc.publisherAmerican Chemical Society (ACS)en
dc.subjectalkanesen
dc.subjectdensity functional theoryen
dc.subjecthydrogenolysisen
dc.subjectsilicaen
dc.subjectsurface organometallic chemistryen
dc.subjecttantalumen
dc.titleMechanism of n-butane hydrogenolysis promoted by Ta-hydrides supported on silicaen
dc.typeArticleen
dc.contributor.departmentKAUST Catalysis Center (KCC)en
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.contributor.departmentChemical Science Programen
dc.identifier.journalACS Catalysisen
kaust.authorCavallo, Luigien
kaust.authorBasset, Jean-Marieen
kaust.authorPasha, Farhan Ahmaden
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