Preparation of Pyridylamido Hafnium Complexes for Olefin Polymerization

Author(s)
박경리
Advisor
이분열
Department
일반대학원 분자과학기술학과
Publisher
The Graduate School, Ajou University
Publication Year
2020-08
Language
eng
Keyword
coordinative chain transfer polymerizationdialkylzincpost-metallocenepyridylamido hafnium complex
Alternative Abstract
The pyridylamido hafnium complex (I) discovered at Dow is a flagship catalyst among postmetallocenes, which are used in the polyolefin industry for PO-chain growth from a chain transfer agent, dialkylzinc. In the present work, with the aim to block a possible deactivation process in prototype compound I, the corresponding derivatives were prepared. A series of pyridylamido Hf complexes were prepared by replacing the 2,6-diisopropylphenylamido part in I with various 2,6-R2C6H3N- moieties (R = cycloheptyl, cyclohexyl, cyclopentyl, 3-pentyl, ethyl, or Ph) or by replacing 2-iPrC6H4C(H)- in I with the simple PhC(H)- moiety. The isopropyl substituent in the 2-iPrC6H4C(H)- moiety influences not only the geometry of the structures (revealed by X-ray crystallography) but also catalytic performance. In the complexes bearing the 2-iPrC6H4C(H)- moiety, the chelation framework forms a plane; however, this framework is distorted in the complexes containing the PhC(H)- moiety. The ability to incorporate a-olefin decreased upon replacing 2-iPrC6H4C(H)- with the PhC(H)- moiety. The complexes carrying the 2,6-di(cycloheptyl)phenylamido or 2,6-di(cyclohexyl)phenylamido moiety (replacing the 2,6-diisopropylphenylamido part in I) showed somewhat higher activity with greater longevity than did prototype catalyst I.
URI
https://dspace.ajou.ac.kr/handle/2018.oak/19823
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Graduate School of Ajou University > Department of Molecular Science and Technology > 3. Theses(Master)
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