Boosting activity, thermostability, and lifetime of iron ethylene polymerization catalysts through gem-dimethyl substitution and incorporation of ortho-cycloalkyl substituents

Boosting activity, thermostability, and lifetime of iron ethylene polymerization catalysts through gem-dimethyl substitution and incorporation of ortho-cycloalkyl substituents Научная публикация

Журнал

Applied Organometallic Chemistry
ISSN: 0268-2605

Вых. Данные

Год: 2021, Том: 35, Номер: 11, Номер статьи : e6376, Страниц : DOI: 10.1002/aoc.6376

Ключевые слова

ethylene polymerization; gem-dimethyl substitution; iron catalyst; linear polyethylene; ortho-cycloalkyl ring size

Авторы

Zhang Randi ^1,2 , Han Mingyang ^1,2 , Oleynik Irina V. ³ , Solan Gregory A. ^1,4 , Oleynik Ivan I. ³ , Ma Yanping ¹ , Liang T. ¹ , Sun Wen-Hua ^1,2

Организации

1	Key Laboratory of Engineering Plastics and Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China
2	CAS Research/Education Center for Excellence in Molecular Sciences, University of Chinese Academy of Sciences, Beijing, China
3	Vorozhtsov Novosibirsk Institute of Organic Chemistry, Novosibirsk, Russian Federation
4	Department of Chemistry, University of Leicester, Leicester, United Kingdom

Six types of ferrous chloride complex, [2-(ArN=CMe)-8-(ArN)-7,7-Me2C9H6N]FeCl2 (Ar=2-(C5H9)-6-MeC6H3 Fe1, 2-(C6H11)-6-MeC6H3 Fe2, 2-(C8H15)-6-MeC6H3 Fe3, 2-(C5H9)-4,6-Me2C6H2 Fe4, 2-(C6H11)-4,6-Me2C6H2 Fe5, 2-(C8H15)-4,6-Me2C6H2 Fe6), each bearing a gem-dimethyl-substituted N,N,N-chelating ligand that differs in the ortho-cycloalkyl ring size and para-substituent of the N-aryl groups, are disclosed. All complexes have been prepared by a straightforward one-flask route and characterized by FT-IR spectroscopy and elemental analysis. In the case of Fe1, oxidation to form the oxo-bridged diferric species [2-(2-(C5H9)-6-MeC6H3N=CMe)-8-(2-(C5H9)-6-MeC6H3N)-7,7-Me2C9H6N]FeCl(μ-O)FeCl3 (Fe1') has been demonstrated and its structural identity confirmed by single crystal X-ray diffraction. Following treatment with either methylaluminoxane (MAO) or modified methylaluminoxane (MMAO), Fe1–Fe6 exhibited optimal catalytic activities at 60°C for ethylene polymerization [up to 2.35 × 107 g of PE (mol of Fe)−1 h−1 for Fe1/MMAO] producing linear polyethylene; even over prolonged run times, high activities were maintained. Moreover, this family of iron catalysts exhibited remarkable thermostability by displaying appreciable activity at temperatures as high as 100°C [activity up to 7.8 × 106 g of PE (mol of Fe)−1 h−1]. By varying the ring size of the ortho-cycloalkyl and para-R2 group (R2 = H, Me), excellent control over molecular weight of the polyethylenes could be achieved with values in the range 1.4–67.8 kg mol−1 obtainable. In addition, end-group analysis of the polymers generated with Fe/MAO or Fe/MMAO revealed that both β-H elimination and chain transfer to aluminum are competitive processes during chain termination. © 2021 John Wiley & Sons, Ltd.

Zhang R. , Han M. , Oleynik I.V. , Solan G.A. , Oleynik I.I. , Ma Y. , Liang T. , Sun W-H.
Boosting activity, thermostability, and lifetime of iron ethylene polymerization catalysts through gem-dimethyl substitution and incorporation of ortho-cycloalkyl substituents
Applied Organometallic Chemistry. 2021. V.35. N11. e6376 . DOI: 10.1002/aoc.6376 WOS Scopus РИНЦ

Web of science	WOS:000673415100001
Scopus	2-s2.0-85110136682
РИНЦ	46897716
OpenAlex	W3182404970