Steady state rate expressions can be derived to distinguish the Cossee–Arlman and metallacycle mechanisms postulated for propylene oligomerization on nickel-based catalysts based on product selectivities, where product selectivities for the former are a function of olefin pressure because sequential coordination and insertion steps lead to independent mechanistic pathways for different hexene isomers. In contrast, the metallacycle mechanism presents pressure-independent product selectivities due to successive coordination prior to the kinetically relevant steps in each mechanism. In this work, steady state propylene oligomerization rates and selectivities were measured in the absence of an activator on nickel functionalized UiO-66 metal organic framework (MOF), Ni/UiO-66, to validate the Cossee–Arlman mechanism for light olefin oligomerization. In situ NO titrations reveal that ~5% of nickel sites were active during the reaction, and thus, not all nickel sites are relevant for catalysis. Propylene dimerization was first order in propylene pressure from 5 to 500 kPa with an apparent activation energy of ~20 kJ mol-1 from 453 to 493 K. Calculated apparent activation energies with density functional theory (DFT) calculations on cluster models of Ni/UiO-66 are in agreement with experiment to corroborate the Cossee–Arlman mechanism. Selectivities of hexene products and the ratio of hexene product selectivities on Ni/UiO-66 are in accordance with selectivity expressions derived from the Cossee–Arlman mechanism. In conclusion, analysis of product selectivities can be used more extensively to demarcate the Cossee–Arlman and metallacycle mechanisms for olefin oligomerization on metal-based catalysts.
Yeh, Benjamin, et al. "Validation of the Cossee–Arlman mechanism for propylene oligomerization on Ni/UiO-66." Catalysis Science and Technology, vol. 13, no. 14, Jun. 2023. https://doi.org/10.1039/d3cy00570d
Yeh, Benjamin, Chheda, Saumil, Zheng, Jian, Schmid, Julian, Löbbert, Laura, Bermejo-Deval, Ricardo, Gutiérrez, Oliver Y., Lercher, Johannes A., Gagliardi, Laura, & Bhan, Aditya (2023). Validation of the Cossee–Arlman mechanism for propylene oligomerization on Ni/UiO-66. Catalysis Science and Technology, 13(14). https://doi.org/10.1039/d3cy00570d
Yeh, Benjamin, Chheda, Saumil, Zheng, Jian, et al., "Validation of the Cossee–Arlman mechanism for propylene oligomerization on Ni/UiO-66," Catalysis Science and Technology 13, no. 14 (2023), https://doi.org/10.1039/d3cy00570d
@article{osti_2000728,
author = {Yeh, Benjamin and Chheda, Saumil and Zheng, Jian and Schmid, Julian and Löbbert, Laura and Bermejo-Deval, Ricardo and Gutiérrez, Oliver Y. and Lercher, Johannes A. and Gagliardi, Laura and Bhan, Aditya},
title = {Validation of the Cossee–Arlman mechanism for propylene oligomerization on Ni/UiO-66},
annote = {Steady state rate expressions can be derived to distinguish the Cossee–Arlman and metallacycle mechanisms postulated for propylene oligomerization on nickel-based catalysts based on product selectivities, where product selectivities for the former are a function of olefin pressure because sequential coordination and insertion steps lead to independent mechanistic pathways for different hexene isomers. In contrast, the metallacycle mechanism presents pressure-independent product selectivities due to successive coordination prior to the kinetically relevant steps in each mechanism. In this work, steady state propylene oligomerization rates and selectivities were measured in the absence of an activator on nickel functionalized UiO-66 metal organic framework (MOF), Ni/UiO-66, to validate the Cossee–Arlman mechanism for light olefin oligomerization. In situ NO titrations reveal that ~5% of nickel sites were active during the reaction, and thus, not all nickel sites are relevant for catalysis. Propylene dimerization was first order in propylene pressure from 5 to 500 kPa with an apparent activation energy of ~20 kJ mol-1 from 453 to 493 K. Calculated apparent activation energies with density functional theory (DFT) calculations on cluster models of Ni/UiO-66 are in agreement with experiment to corroborate the Cossee–Arlman mechanism. Selectivities of hexene products and the ratio of hexene product selectivities on Ni/UiO-66 are in accordance with selectivity expressions derived from the Cossee–Arlman mechanism. In conclusion, analysis of product selectivities can be used more extensively to demarcate the Cossee–Arlman and metallacycle mechanisms for olefin oligomerization on metal-based catalysts.},
doi = {10.1039/d3cy00570d},
url = {https://www.osti.gov/biblio/2000728},
journal = {Catalysis Science and Technology},
issn = {ISSN 2044-4753},
number = {14},
volume = {13},
place = {United States},
publisher = {Royal Society of Chemistry},
year = {2023},
month = {06}}
Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences & Biosciences Division (CSGB); National Science Foundation (NSF)
Grant/Contract Number:
AC05-76RL01830; SC0012702; SC0023383
OSTI ID:
2000728
Alternate ID(s):
OSTI ID: 1987971
Report Number(s):
PNNL-SA--186936
Journal Information:
Catalysis Science and Technology, Journal Name: Catalysis Science and Technology Journal Issue: 14 Vol. 13; ISSN 2044-4753