Asymmetric carbon-bridged diphosphine based chromium complexes for selective ethylene tri-/tetramerization with high thermal stability

Ma, Jing; Fan, Haonan; Hao, Biao‐Biao; Jiang, Yan; Wang, Libo; Wang, Xun; Zhang, Jingyi; Jiang, Tao

doi:10.1016/j.jcat.2022.06.008

Cited by 17 publications

(9 citation statements)

References 40 publications

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“…Therefore, multinuclear ligands are worthy of further exploration for industrialization. (180)(181)(182)(183). 85 Minor changes in the structure and reaction conditions led to the tetramerization of ethylene, rather than its trimerization.…”

Section: Dual/multinuclear Pnp Ligandsmentioning

confidence: 99%

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Selective ethylene tetramerization: an overview

Hao

Alam

Jiang

et al. 2023

Inorg. Chem. Front.

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Section: Dual/multinuclear Pnp Ligandsmentioning

confidence: 99%

“…28) and tested them for ethylene oligomerization. 183 Steric interactions in these ligands significantly impacted the activity and product distribution. Because of their steric bulk, the ligands 253 and 254 (R = Et/ i Pr) formed only small amounts of C 6 byproducts-a significant feature for potential industrialization.…”

Section: Dual/multinuclear Pnp Ligandsmentioning

confidence: 99%

Selective ethylene tetramerization: an overview

Hao

Alam

Jiang

et al. 2023

Inorg. Chem. Front.

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“…Catalyst development for selective olefin oligomerization remains a hot research topic in both academia and industry. [35][36][37][38][39][40][41][42][43][44][45] Cr complexes with privileged ligands are instrumental in numerous catalytic processes. 46,47…”

Section: Introductionmentioning

confidence: 99%

Preparation of chromium complexes for ethylene tetramerization catalyst

Park,

Baek

et al. 2024

Bulletin Korean Chem Soc

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One of the remaining challenges in the commercialization of a highly efficient ethylene tetramerization catalyst, [1‐CrCl2][B(C6F5)4] (1=iPrN[P(C6H4Si(Octyl)3)2]2), is the generation of small amounts of polyethylene (PE). To address this issue, we explored different activator options and found that (Octyl)3Al was the most effective choice. Building on the observation that [iPrN(PPh2)2]CrCl3(THF) was not completely alkylated by the action of excess Me3Al to form ([iPrN(PPh2)2]Cr(μ2‐Cl)(ClMe2AlClAlMe3))2, we synthesized [ortho‐(MeO)C6H4CH2‐η1C:κO]3Cr, developing a catalytic system comprising this precursor, PNP ligand 1, and [MeN(H)(C18H37)2][B(C6F5)4]. However, this catalytic system exhibited a long induction time (~30 min) and generated a significant amount of PE. Returning to the catalytic system of [1‐CrCl2][B(C6F5)4], we successfully achieved the conversion of [(EtOH)4CrCl2][B(C6F5)4] to [(CH3CN)4CrCl2][B(C6F5)4] at a large scale by designing a specialized glass apparatus. Finally, we discovered that the generation of PE could be reduced by adjusting the reaction conditions during the synthesis of [1‐CrCl2][B(C6F5)4].

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“…The first selective ethylene tri/tetramerization system with Cr-based catalysts containing bis(diphenylphosphino)-amine (PNP), bis(diphenylphosphino) hydrazine (PNNP), or 1,2-bis(diphenylphosphino)ethane (dppe) ligand was discovered by Sasol in 2004. , A selectivity of 68.3% for 1-octene was obtained at 45 bar and 45 °C, along with the remaining products, which include 1-hexene, C 6 impurities, oligomers with higher carbon number, and polyethylene. Subsequently, in order to further improve the ethylene tri/tetramerization performance, typical PCCP, − PCN, PC 2 NCN, PCNP, PCSiNP, PNCN, , PNCNP, and PNPN , backbone ligands have been studied. Results show that multidentate ligands containing P and N donors have great potential to catalyze the selective ethylene oligomerization, yielding 1-hexene and 1-octene with high selectivities. , In a previous work, Yang and co-workers introduced the pyridine–phosphine (PNCN) ligand variations by modifying the phosphine substituents, which affected the ligand bite angles and flexibility .…”

Section: Introductionmentioning

confidence: 99%

Chromium-Based Complexes Bearing Aminophosphine and Phosphine–Imine–Pyrryl Ligands for Selective Ethylene Tri/Tetramerization

Liu

Liu²,

Yang³

et al. 2023

ACS Omega

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A series of Cr-based complexes 6−10 bearing aminophosphine (P,N) ligands Ph 2 P−L−NH 2 [L = CH 2 CH 2 (1), L = CH 2 CH 2 CH 2 (2), and L = C 6 H 4 CH 2 (3)] and phosphine−imine− pyrryl (P,N,N) ligands 2-(Ph 2 P−L−N�CH)C 4 H 3 NH [L = CH 2 CH 2 CH 2 ( 4) and L = C 6 H 4 CH 2 (5)] were prepared, and their catalytic properties were examined for ethylene tri/tetramerization. Xray crystallographic analysis of complex 8 indicated the κ 2 -P,N bidentate coordination mode at the Cr(III) center and the distorted octahedral geometry of monomeric P,N−CrCl 3 . Upon activation by methylaluminoxane (MAO), complexes 7−8 bearing P,N (PC 3 N backbone) ligands 2−3 showed good catalytic reactivity for ethylene tri/tetramerization. On the other hand, complex 6 bearing the P,N (PC 2 N backbone) ligand 1 was found active for non-selective ethylene oligomerization, while complexes 9−10 bearing P,N,N ligands 4−5 only produced polymerization products. In particular, the high catalytic activity of 458.2 kg/(g•Cr•h), excellent selectivity of 90.9% (1-hexene and 1-octene combined), and extremely low PE content of 0.1% were obtained with complex 7 in toluene at 45 °C and 45 bar. These results suggest that rational control of P,N and P,N,N ligand backbones, including a carbon spacer and rigidity of a carbon bridge, can lead to the high-performance catalyst for the ethylene tri/tetramerization process.

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Asymmetric carbon-bridged diphosphine based chromium complexes for selective ethylene tri-/tetramerization with high thermal stability

Cited by 17 publications

References 40 publications

Selective ethylene tetramerization: an overview

Selective ethylene tetramerization: an overview

Preparation of chromium complexes for ethylene tetramerization catalyst

Chromium-Based Complexes Bearing Aminophosphine and Phosphine–Imine–Pyrryl Ligands for Selective Ethylene Tri/Tetramerization

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