Alkane metathesis by a tungsten carbyne complex grafted on gamma alumina: Is there a direct chemical role of the support?

Joubert, Jérôme; Delbecq, Françoise; Sautet, Philippe

doi:10.1016/j.jcat.2007.07.035

Cited by 27 publications

(46 citation statements)

References 33 publications

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“…Surprisingly, the results showed even better activity than pre-catalyst 1 (see Figure S3). 20 However, these findings are not consistent with our experimental studies because 3 is also active for cyclooctane metathesis. The product distribution showed shorter cyclic alkanes (cyclopentane, cyclohexane and cycloheptane) for precatalyst 3. n-Decane is also transformed into metathesis products by 3 with TONs of 136 (see Figure S4).…”

Section: Introductioncontrasting

confidence: 82%

Simple addition of silica to an alkane solution of a Wilkinson WMe₆ or Schrock W alkylidyne complex gives an active complex for saturated and unsaturated hydrocarbon metathesis

et al. 2015

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The addition of partially dehydroxylated silica (PDS) to a solution of the Wilkinson WMe6 as well as the Schrock W neopentylidyne tris neopentyl complex catalyzes linear or cyclic alkanes to produce respectively a distribution of linear alkanes from methane up to triacontane or a mixture of cyclic and macrocyclic hydrocarbons. This single catalytic system transforms also linear α-olefins into higher and lower homologues via an isomerization/metathesis mechanism (ISOMET). This complex is also efficient towards functionalized olefins. Unsaturated fatty acid esters (FAEs) are converted into diesters corresponding to self-metathesis products.

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Section: Introductioncontrasting

confidence: 82%

Simple addition of silica to an alkane solution of a Wilkinson WMe₆ or Schrock W alkylidyne complex gives an active complex for saturated and unsaturated hydrocarbon metathesis

et al. 2015

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“…Al-OH on c-Al 2 O 3 is 4/nm 2[50]. Because there are also Al-O-Al groups in addition to Al-OH groups on c-Al 2 O 3 , the surface coverage of Ti species in our case is well below one monolayer.…”

mentioning

confidence: 63%

Novel Au/TiO2/Al2O3 · xH2O catalysts for CO oxidation

Yan

Mahurin

et al. 2007

Catal Lett

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Á xH 2 O (x = 0-3) catalysts were prepared by assembling gold nanoparticles on neat and TiO 2 -modified Al 2 O 3 , AlOOH, and Al(OH) 3 supports, and their catalytic activity in CO oxidation was tested either as synthesized or after on-line pretreatment in O 2 -He at 500°C. A promotional effect of TiO 2 on the activity of gold catalysts was observed upon 500°C-pretreatment. The catalyst stability as a function of time on stream was tested in the absence or presence of H 2 , and physiochemical characterization applying BET, ICP-OES, XRD, TEM, and 27 Al MAS NMR was conducted.

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“…34 Sautet and co-workers computationally studied the C–H activation of methane and propane on γ-Al 2 O 3 (110) on several catalytic sites (e.g Al III –O II and Al III –O III ) through the polar pathway. 31,32,35,36 The authors also investigated the effect of surface hydration on methane activation on these sites. C–H activation of methane can potentially occur through the polar 16−18 or radical mechanism.…”

Section: Introductionmentioning

confidence: 99%

Computational Study of Methane Activation on γ-Al₂O₃

2018

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The C–H activation of methane remains a longstanding challenge in the chemical industry. Metal oxides are attractive catalysts for the C–H activation of methane due to their surface Lewis acid–base properties. In this work, we applied density functional theory calculations to investigate the C–H activation mechanism of methane on various sites of low-index facets of γ-Al 2 O 3 . The feasibility of C–H activation on different metal–oxygen (acid–base) site pairs was assessed through two potential mechanisms, namely, the radical and polar. The effect of surface hydroxylation on C–H activation was also investigated to examine the activity of γ-Al 2 O 3 under realistic catalytic surface conditions (hydration). On the basis of our calculations, it was demonstrated that the C–H activation barriers for polar pathways are significantly lower than those of the radical pathways on γ-Al 2 O 3 . We showed that the electronic structure (s- and p-band center) for unoccupied and occupied bands can be used to probe site-dependent Lewis acidity and basicity and the associated catalytic behavior. We identified the dissociated H 2 binding and final state energy as C–H activation energy descriptors for the preferred polar pathway. Finally, we developed structure–activity relationships for the C–H activation of methane on γ-Al 2 O 3 that account for surface Lewis acid–base properties and can be utilized to accelerate the discovery of catalysts for methane (and shale gas) upgrade.

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Alkane metathesis by a tungsten carbyne complex grafted on gamma alumina: Is there a direct chemical role of the support?

Cited by 27 publications

References 33 publications

Simple addition of silica to an alkane solution of a Wilkinson WMe₆ or Schrock W alkylidyne complex gives an active complex for saturated and unsaturated hydrocarbon metathesis

Simple addition of silica to an alkane solution of a Wilkinson WMe₆ or Schrock W alkylidyne complex gives an active complex for saturated and unsaturated hydrocarbon metathesis

Novel Au/TiO2/Al2O3 · xH2O catalysts for CO oxidation

Computational Study of Methane Activation on γ-Al₂O₃

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Alkane metathesis by a tungsten carbyne complex grafted on gamma alumina: Is there a direct chemical role of the support?

Cited by 27 publications

References 33 publications

Simple addition of silica to an alkane solution of a Wilkinson WMe6 or Schrock W alkylidyne complex gives an active complex for saturated and unsaturated hydrocarbon metathesis

Simple addition of silica to an alkane solution of a Wilkinson WMe6 or Schrock W alkylidyne complex gives an active complex for saturated and unsaturated hydrocarbon metathesis

Novel Au/TiO2/Al2O3 · xH2O catalysts for CO oxidation

Computational Study of Methane Activation on γ-Al2O3

Contact Info

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Simple addition of silica to an alkane solution of a Wilkinson WMe₆ or Schrock W alkylidyne complex gives an active complex for saturated and unsaturated hydrocarbon metathesis

Simple addition of silica to an alkane solution of a Wilkinson WMe₆ or Schrock W alkylidyne complex gives an active complex for saturated and unsaturated hydrocarbon metathesis

Computational Study of Methane Activation on γ-Al₂O₃