Iron(II)–ethylene polymerization catalysts bearing 2,6-bis(imino)pyrazine ligands

Beaufort, Laurence; Benvenuti, Federica; Noels, Alfred F.

doi:10.1016/j.molcata.2006.07.005

Cited by 22 publications

(15 citation statements)

References 22 publications

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“…The properties of the central ring were tuned by introduction of additional N-atoms in the heterocycle. [17][18][19][20][21] Less basic heterocycles such as pyrimidine in 1 or pyrazine in 2 led to lower activities of the corresponding iron catalysts in ethylene oligomerization or polymerization compared to the bis(imino)pyridine-based catalysts, with values of 10 5 g (mol h atm) À1 and 10 8 g (mol h atm) À1 , respectively (under 1 to 4 atm and at 25 to 50 1C). 9,11,17 While with a triazine moiety, as in ligands 3 and 4 (Scheme 3), attempts at coordination to iron failed.…”

Section: Modifications Of the Central Ringmentioning

confidence: 99%

Ethylene oligomerization using iron complexes: beyond the discovery of bis(imino)pyridine ligands

et al. 2014

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Since the discovery that bis(imino)pyridine ligands are able to confer high activities in ethylene oligomerization and polymerization to their iron complexes, considerable attention has been focused on catalyst design for these reactions and this research constitutes an ever-growing area in molecular catalysis. The tuning of the ligand structures and properties, and thus of catalysts, generally represents the basis for subsequent work contributing to process development and industrialization. Significant effort is therefore devoted to generate structural diversity in order to access the required catalyst stability and selectivity. This feature article outlines nitrogen-containing ligands that have been developed for the iron-catalyzed oligomerization of ethylene since the seminal discovery of the properties of bis(imino)pyridine ligands.

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Section: Modifications Of the Central Ringmentioning

confidence: 99%

Ethylene oligomerization using iron complexes: beyond the discovery of bis(imino)pyridine ligands

et al. 2014

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“…While the 2,6-bis(imino)pyridine ligand frame has continued to lead the way, the past 10 years has also seen the development of alternative ligand sets that can act as compatible supports for iron and cobalt ethylene oligomerisation/polymerisation catalysts ( Table 4 ) [46,50,181,182,183,184,185,186,187,188,189,190,191,192,193,194,195,196,197,198,199,200,201,202,203,204,205,206,207,208,209] ; active catalysts based on bimetallic iron and cobalt precatalysts have also started to emerge ( Table 5 ) [54,210,211,212,213,214,215] . In the main, these systems show lower activities than the prototype bis(imino)pyridine-based catalysts, although several of these systems have significantly started to approach their catalytic performances (e.g.…”

Section: Alternative Iron and Cobalt Catalystsmentioning

confidence: 99%

Iron-Based and Cobalt-Based Olefin Polymerisation Catalysts

Gibson¹,

Solan²

2008

Topics in Organometallic Chemistry

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This chapter describes the brief history of iron or cobalt catalysts for olefin polymerisation and oligomerisation. Since the discovery in 1998 that 2,6-bis(imino)pyridine iron and cobalt halides, on activation with MAO, can convert ethylene to highly linear polyethylene, numerous reports have been concerned with ligand modification, mechanisms for precatalyst activation, identifying the active species and understanding the mode of propagation/chain transfer. In addition, heterogenisation of this class of catalysts, their incorporation into macrocycles/ polymers and their use in reactor blending/tandem catalysis has seen some important developments; alternative ligand architectures that can support active iron and cobalt catalysts are also discussed as are different types of olefinic monomer.

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“…Therefore, the EIS showed a capacitive loop at IFs. For the large inductive loop at LFs, it originated from the disturbance induced by the redissolution of the oxide layer [36,37]. Model A in Figure 9 could well fit the EIS.…”

Section: Electrochemical Impedance Spectroscopy (Eis) Analysismentioning

confidence: 88%

Influence of Sealing Treatment on the Corrosion Resistance of PEO Coated Al-Zn-Mg-Cu Alloy in Various Environments

et al. 2019

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In the present work, a coating was prepared on an Al alloy substrate by plasma electrolytic oxidation (PEO). To seal the micro defects in the oxide scale, a siloxane layer was prepared on the PEO coating by sol gel method. The polymer sealant was synthesized from Tetraethoxy silane (TEOS) and methacryloxy propyl trimethoxyl silane (MPTES). The chemical structure of the polymer was studied by Fourier transform infrared spectroscopy (FTIR). The morphologies and microstructure of the PEO coating and siloxane coating were investigated by scanning electron microscopy (SEM). The results showed that siloxane formed a continuous layer on the surface and effectively sealed the micro defects. The corrosion behavior of the coatings in three different corrosion solutions (NaCl, HCl, and NaOH) was examined by electrochemical impedance spectroscopy and potentiodynamic polarization. The corrosion resistance of the sealed coatings was superior to that of the PEO coating because it prevented the penetration of corrosive solutions. The corrosion resistance of the sealed coatings was found to decrease with increasing electrolyte concentration. The work demonstrated that siloxane sealing may greatly enhance the corrosion resistance of Al-based PEO coating in acidic, neutral, and alkaline environments.

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Iron(II)–ethylene polymerization catalysts bearing 2,6-bis(imino)pyrazine ligands

Cited by 22 publications

References 22 publications

Ethylene oligomerization using iron complexes: beyond the discovery of bis(imino)pyridine ligands

Ethylene oligomerization using iron complexes: beyond the discovery of bis(imino)pyridine ligands

Iron-Based and Cobalt-Based Olefin Polymerisation Catalysts

Influence of Sealing Treatment on the Corrosion Resistance of PEO Coated Al-Zn-Mg-Cu Alloy in Various Environments

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