Research output: Contribution to journal › Article › peer-review
Origin of "multisite-like" ethylene polymerization behavior of the single-site nonsymmetrical bis(imino)pyridine iron(II) complex in the presence of modified methylaluminoxane. / Semikolenova, Nina V.; Sun, Wen Hua; Soshnikov, Igor E. et al.
In: ACS Catalysis, Vol. 7, No. 4, 07.04.2017, p. 2868-2877.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - Origin of "multisite-like" ethylene polymerization behavior of the single-site nonsymmetrical bis(imino)pyridine iron(II) complex in the presence of modified methylaluminoxane
AU - Semikolenova, Nina V.
AU - Sun, Wen Hua
AU - Soshnikov, Igor E.
AU - Matsko, Mikhail A.
AU - Kolesova, Olga V.
AU - Zakharov, Vladimir A.
AU - Bryliakov, Konstantin P.
PY - 2017/4/7
Y1 - 2017/4/7
N2 - A detailed study of the effect of reaction temperature, time, and cocatalyst composition on the ethylene polymerization performance of 2-[1-(2,6-dibenzhydryl-4-chlorophenylimino)ethyl]-6-(1-mesityliminoethyl)pyridyliron dichloride (1) is reported. In the presence of modified methylaluminoxane (MMAO), 1 behaves like a highly active, "multisite-like" ethylene polymerization catalyst, with the resulting polyethylenes having time-dependent bimodal-like molecular-weight distributions and featuring saturated (n-propyl- and i-butyl-terminated) chain ends. To readily distinguish between bimodal and bimodal-like molecular-weight distributions, we have proposed the use of the dNf/(d log M) - log M representation further to the mainstream dWf/(d log M) - log M one. The consensus mechanism of chain transfer and chain-end formation in the presence of MMAO has been proposed, which explains the composition and amount of terminal alkyl groups in the polymer, and the apparent "multisite-like" nature of the iron catalyst. A comparison between the catalytic behaviors of the "multisite-like" 1/MMAO catalyst system and the truly multisite catalyst system based on Brookhart's symmetrical bis(imino)pyridine iron catalyst 2 is given. (Graph Presented).
AB - A detailed study of the effect of reaction temperature, time, and cocatalyst composition on the ethylene polymerization performance of 2-[1-(2,6-dibenzhydryl-4-chlorophenylimino)ethyl]-6-(1-mesityliminoethyl)pyridyliron dichloride (1) is reported. In the presence of modified methylaluminoxane (MMAO), 1 behaves like a highly active, "multisite-like" ethylene polymerization catalyst, with the resulting polyethylenes having time-dependent bimodal-like molecular-weight distributions and featuring saturated (n-propyl- and i-butyl-terminated) chain ends. To readily distinguish between bimodal and bimodal-like molecular-weight distributions, we have proposed the use of the dNf/(d log M) - log M representation further to the mainstream dWf/(d log M) - log M one. The consensus mechanism of chain transfer and chain-end formation in the presence of MMAO has been proposed, which explains the composition and amount of terminal alkyl groups in the polymer, and the apparent "multisite-like" nature of the iron catalyst. A comparison between the catalytic behaviors of the "multisite-like" 1/MMAO catalyst system and the truly multisite catalyst system based on Brookhart's symmetrical bis(imino)pyridine iron catalyst 2 is given. (Graph Presented).
KW - Bis(imino)pyridine
KW - Chain transfer
KW - Ethylene polymerization
KW - MMAO
KW - Molecular-weight distribution
KW - Multisite catalysts
KW - bis(imino)pyridine
KW - molecular-weight distribution
KW - ACTIVATION
KW - PRECATALYSTS
KW - 2,6-BIS(IMINO)PYRIDYL COMPLEXES
KW - ethylene polymerization
KW - POLYETHYLENE
KW - FE(II)
KW - multisite catalysts
KW - chain transfer
KW - NEW-GENERATION
KW - CATALYSTS
KW - COBALT
UR - http://www.scopus.com/inward/record.url?scp=85019085389&partnerID=8YFLogxK
U2 - 10.1021/acscatal.7b00486
DO - 10.1021/acscatal.7b00486
M3 - Article
AN - SCOPUS:85019085389
VL - 7
SP - 2868
EP - 2877
JO - Topics in Catalysis
JF - Topics in Catalysis
SN - 1022-5528
IS - 4
ER -
ID: 10193687