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Ethene Dimerization on Zeolite-Hosted Ni Ions: Reversible Mobilization of the Active Site.

ABSTRACT: The active site in ethene oligomerization catalyzed by Ni-zeolites is proposed to be a mobile Ni(II) complex, based on density functional theory-based molecular dynamics (DFT-MD) simulations corroborated by continuous-flow experiments on Ni-SSZ-24 zeolite. The results of the simulations at operating conditions show that ethene molecules reversibly mobilize the active site as they exchange with the zeolite as ligands on Ni during reaction. Microkinetic modeling was conducted on the basis of free-energy profiles derived with DFT-MD for oligomerization on these mobile [(ethene)₂-Ni-alkyl]⁺ species. The model reproduces the experimentally observed high selectivity to dimerization and indicates that the mechanism is consistent with the observed second-order rate dependence on ethene pressure.

SUBMITTER: Brogaard RY

PROVIDER: S-EPMC6559053 | biostudies-literature | 2019 Jun

REPOSITORIES: biostudies-literature

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Ethene Dimerization on Zeolite-Hosted Ni Ions: Reversible Mobilization of the Active Site.

Brogaard Rasmus Yding RY Kømurcu Mustafa M Dyballa Michael Martin MM Botan Alexandru A Van Speybroeck Veronique V Olsbye Unni U De Wispelaere Kristof K

ACS catalysis 20190522 6

The active site in ethene oligomerization catalyzed by Ni-zeolites is proposed to be a mobile Ni(II) complex, based on density functional theory-based molecular dynamics (DFT-MD) simulations corroborated by continuous-flow experiments on Ni-SSZ-24 zeolite. The results of the simulations at operating conditions show that ethene molecules reversibly mobilize the active site as they exchange with the zeolite as ligands on Ni during reaction. Microkinetic modeling was conducted on the basis of free- ...[more]

PMID: 31205799

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