Chromium N-phosphinoamidine ethylene tri-/tetramerization catalysts: Designing a step change in 1-octene selectivity

Ogawa, Tetsuya; Lindeperg, Fabien; Stradiotto, Mark; Turculet, Laura; Sydora, Orson L.

doi:10.1016/j.jcat.2020.10.021

Cited by 18 publications

(16 citation statements)

References 36 publications

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“…The most common ligands used in chromium-based catalysts for ethylene tri/tetramerization are PNP and alternative diphosphines including PNNP, PCP, PCCP, PCNCP, or PN(C) n NP scaffolds. − Since the ligands can stabilize the particular oxidation state and regulate the product selectivity, the ligand modification on the structure and electron will affect the catalytic selectivity. , It has been proved that the catalytic performance of chromium-based complexes bearing tridentate PNP, PSP, and SPS ligands with S-substitution can be improved . Furthermore, the PNP ligands with tunable substituents on both N and P atoms are in favor of regulating the electron distribution and the steric bulk of the Cr center, which can produce the CrC 6 or CrC 6 /CrC 8 metallocycles that can promote the selectivity of 1-C 6 and 1-C 8 . , As reported, those Cr-based complexes bridging PNP ligands with the high steric bulks at backbone N (Chart A–D) have shown good catalytic activity and selectivity toward 1-octene and 1-hexene production .…”

Section: Introductionmentioning

confidence: 99%

Chromium-Based Complexes Bearing N-Substituted Diphosphinoamine Ligands for Ethylene Oligomerization

Liu

Yang²,

Li³

et al. 2022

ACS Omega

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A range of novel N-substituted diphosphinoamine (PNP) ligands Ph 2 PN(R)PPh 2 [R = F 2 CHCH 2 (1); R = Me 2 CHCH 2 (2); R = Me 2 CHCH 2 CH 2 (3)] have been synthesized via one-step salt elimination reaction. The ligand-coordinated chromium carbonyls [Ph 2 PN(R)PPh 2 ]Cr(CO) 4 (4−6) were further synthesized, and X-ray crystallography analysis of complex 6 revealed the κ 2 -P,P bidentate binding mode of Cr center and the molecular structure of PNP ligand 3. Then the catalytic ethylene oligomerization behaviors of PNP ligands 1−3 bridging chromium chloride complexes {[Ph 2 PN(R)PPh 2 ]CrCl 2 (μ-Cl)} 2 (7−9) were further discussed in depth. Experimental results showed that complex 7 with the strong electron-withdrawing F 2 CHCH 2 group can promote the nonselective ethylene oligomerization, while both complex 8 and complex 9 with the electron-donating Me 2 CHCH 2 and Me 2 CHCH 2 CH 2 groups can significantly enhance the selective ethylene tri/tetramerization. The good catalytic activity of 198.3 kg/(g Cr•h), the selectivity toward 1-hexene and 1-octene of 76.4%, and the low PE content of 0.2% were simultaneously achieved with the Al/Cr molar ratio of 600 using the complex 8/MMAO system at 45 °C and 45 bar. These excellent results were mainly attributed to the fact that the β-branching of bridging ligand 2 increased the steric bulk of the N-moiety for complex 8.

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Section: Introductionmentioning

confidence: 99%

Chromium-Based Complexes Bearing N-Substituted Diphosphinoamine Ligands for Ethylene Oligomerization

Liu

Yang²,

Li³

et al. 2022

ACS Omega

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“…However, the 1-hexene selectivity (wt % of 1-hexene in the C 6 fraction) decreased from 97.3 to 94.6 wt% upon reducing the reaction temperature from 70 to 50 °C at ethylene pressure of 60 bar, while purity of 1-octene did not change significantly. The ratio of 1-hexene-to-1-octene can be tuned by changing the steric environment around chromium metal [53]. The extensive literature search showed that the catalyst 10 is the one most active catalyst (54,670 kg C/ mol Cr/h, 70 °C, TOF = 560 s −1 ) for chromium catalysed ethylene trimerization reaction.…”

Section: Chevron's Cr-phosphanylamidinate Catalyst Systemmentioning

confidence: 99%

Industrially relevant ethylene trimerization catalysts and processes

2021

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Abstract1-Hexene is one of the comonomers used to produce mainly low linear density polyethylene (LLDPE) and high-density polyethylene (HDPE). The production of 1-hexene by ethylene trimerization method gained much interest in petrochemical industry due to its high selectivity towards 1-hexene in comparison to traditional ethylene oligomerization method. In literature, many catalyst systems are reported for ethylene trimerization reaction, but only few of them qualify for the commercial applications. In the present review, activity and selectivity of commercially viable catalyst systems and amount of polyethylene formed as a by-product on using these catalyst systems were discussed. Special attention is given to Chevron Phillips ethylene trimerization technology which is one of the dominant technologies in the production of 1-hexene. The challenges such as fouling issues at commercial plant due to polyethylene by-product formation were discussed and the progress made to overcome the challenges were also discussed. New generation nontoxic titanium catalysts look promising and challenges involved in commercializing these catalysts were presented in the review. Graphic abstract

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“…In recent years, researchers from academia and industry have paid much attention to the study of ethylene trimerization and tetramerization. [4][5][6][7][8][9] Chromium-based catalysts have been extensively investigated for selective ethylene oligomerization, in comparison to catalysts based on tantalum, 10,11 titanium, [12][13][14] etc. In 2003, Phillips Petroleum Company put the first ethylene trimerization plant into operation for the production of 1-hexene in Qatar.…”

Section: Introductionmentioning

confidence: 99%

“…In recent years, researchers from academia and industry have paid much attention to the study of ethylene trimerization and tetramerization. 4–9…”

Section: Introductionmentioning

confidence: 99%

Cr/PCCP-catalysed selective ethylene oligomerization: analysis of various conformations and the hemilabile methoxy group

Zhong

Liu

Xia

et al. 2022

Catal. Sci. Technol.

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Chromium N-phosphinoamidine ethylene tri-/tetramerization catalysts: Designing a step change in 1-octene selectivity

Cited by 18 publications

References 36 publications

Chromium-Based Complexes Bearing N-Substituted Diphosphinoamine Ligands for Ethylene Oligomerization

Chromium-Based Complexes Bearing N-Substituted Diphosphinoamine Ligands for Ethylene Oligomerization

Industrially relevant ethylene trimerization catalysts and processes

Cr/PCCP-catalysed selective ethylene oligomerization: analysis of various conformations and the hemilabile methoxy group

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