Highly Selective Heterogeneous Ethylene Dimerization with a Scalable and Chemically Robust MOF Catalyst

Abstract

Metal-organic frameworks (MOFs) hold great promise as structurally tunable catalysts capable of high selectivity in the solid state, yet their comparatively high cost and often limited stability remain significant concerns for their commercialization as heterogeneous catalysts. Here, we report detailed X-ray absorption spectroscopy studies of Co-and Ni-MFU-4l, a class of highly selective MOF catalysts for olefin upgrading, and reveal mechanisms that lead to their deactivation. We further show that Ni-CFA-1, a more scalable and economical alternative to Ni-MFU-4l, reproduces both the local coordination structure and the high selectivity of the latter in ethylene dimerization catalysis. Under optimal conditions, Ni-CFA-1 activated by MMAO-12 achieves a turnover frequency of 37,100 per hour and a selectivity of 87.1% for 1-butene, a combination of activity, selectivity, and affordability that is unmatched among heterogeneous ethylene dimerization catalysts. Ni-CFA-1 retains its high activity for at least 12 hours in a oneliter semi-batch reactor, offering a strategy toward robust and scalable MOFs for industrial catalysis.

Gas reactions under intrapore condensation regime within tailored metal–organic framework catalysts

“…However, there are several challenges to render these materials into practice in large-scale processes. For instance, remarkable ethylene dimerization turnovers were obtained using Ni-containing MOFs 12–20 , but they still require large amounts of activators (up to 500 equivalents per active metal) to generate the active species. Moreover, the Ni-MOF catalysts undergo fast deactivation 12 .…”

Influence of linkers on the Kuratowski-type secondary building unit in nickel single-site MOFs for ethylene oligomerization catalysis: a computational study

“…The Dinca group used a low loading of Ni (<7.5%) to exchange only one site of the four peripheral Zn environments behaving as a single-site platform catalytically active for ethylene coordination. 15 However, there is no experimental evidence on the exact location of the exchanged metal ions on this MOF, and thus which site is most favored for a metal ion exchange. According to Li and co-workers, some important aspects to consider are; the first coordination sphere in which the metal ion is weakly bound to a ligand, the reaction conditions, and the diffusibility of the metal ions entering the MOF.…”

“…18 A similar trend is observed for Ni-CFA-1. 15 Therefore, increasing the temperature increases the probability of getting higher chain growth, although 1-butene is still the main product. Based on this experimental evidence, we evaluate the effect of temperature on activity and selectivity.…”

Theoretical Insight into the Effect of Fluorine‐Functionalized Metal‐Organic Framework Supported Palladium Single‐Site Catalyst in the Ethylene Dimerization Reaction

“…Single-point energies were computed at the same level of theory with the SMD model in toluene as solvent according to the experimental reports for Ni-CFA-1 and Co-CFA-1 MOF catalysts. [16] On the other hand, it is known that Ni-CFA-1 can efficiently catalyze the ED reaction upon activation with MMAO, [16] which, together with the pore channel, may significantly affect the catalytic properties in ED on this MOF. Notwithstanding, the effect of the co-catalyst will not be the focus of this study.…”