Journal of Polymer Science, Part A: Polymer Chemistry, Volume (51), Year (2013-1) , Pages (1520-1532)

Title : ( Synthesis and Structural Characterization of a Nickel(II) Precatalyst Bearing a b-Triketimine Ligand and Study of Its Ethylene Polymerization Performance Using Response Surface Methods )

Authors: Nona Ghasemi Hamedani , Hassan Arabir , Gholamhossein Zohuri , F. S. Mair , A. Jolleys ,

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ABSTRACT: The reaction of N-(4-(mesitylamino)pent-3-en-2-ylidene)- 2,4,6-trimethylbenzenamine (1) with n-butyl lithium and then with N-(2,4,6-trimethyl-phenyl)-acetimidoyl chloride yields a new b-triketimine ligand, N-(4-(mesitylamino)-3-(1-(mesitylimino) ethyl)pent-3-en-2-ylidene)-2,4,6-trimethylbenzenamine, 2. The addition of 2 to nickel (II) dibromide 1,2-dimethoxyethane (NiBr2(DME)) in the presence of [Na]þ[3,5-(CF3)4C6H3]4B]_ (NaBAr’4) gives a five-coordinate dimeric complex [(2.NiBr)2].2 [(BAr’4)], 3. The structure of 3 has been determined by single crystal X-ray diffraction. This complex generates catalytically active species for the homopolymerization of ethylene in combination with methylaluminoxane to produce elastomeric, branched polyethylene. The effect of factors (temperature, pressure, and cocatalyst to catalyst molar ratio (CC)) on the polymerization process has been investigated using regression models of responses (catalyst activity, crystallinity, and weight-average molecular weight of polymer (Mw)) and visualized via the response surface method (RSM). Activity and Mw responses show a second-order variation with temperature and vary linearly with pressure. Conversely, crystallinity follows a secondorder model while varying temperature, pressure, and CC. Furthermore, a set of polymerization conditions for reaching desirable responses was predicted and then experimentally verified. The activities achieved challenge the best reported activities for Ni(II) catalysts with b-connected imine ligand supports, but fall short of those for a-diimines. VC 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 1520–1532. KEYWORDS: b-triketimine ligand; Ni polymerization catalysts; polyethylene (PE); response surface method

Keywords

, KEYWORDS: b, triketimine ligand; Ni polymerization catalysts; polyethylene (PE); response surface
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@article{paperid:1034681,
author = {Nona Ghasemi Hamedani and Hassan Arabir and Zohuri, Gholamhossein and F. S. Mair and A. Jolleys},
title = {Synthesis and Structural Characterization of a Nickel(II) Precatalyst Bearing a b-Triketimine Ligand and Study of Its Ethylene Polymerization Performance Using Response Surface Methods},
journal = {Journal of Polymer Science, Part A: Polymer Chemistry},
year = {2013},
volume = {51},
month = {January},
issn = {0887-624x},
pages = {1520--1532},
numpages = {12},
keywords = {KEYWORDS: b-triketimine ligand; Ni polymerization catalysts; polyethylene (PE); response surface method},
}

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%0 Journal Article
%T Synthesis and Structural Characterization of a Nickel(II) Precatalyst Bearing a b-Triketimine Ligand and Study of Its Ethylene Polymerization Performance Using Response Surface Methods
%A Nona Ghasemi Hamedani
%A Hassan Arabir
%A Zohuri, Gholamhossein
%A F. S. Mair
%A A. Jolleys
%J Journal of Polymer Science, Part A: Polymer Chemistry
%@ 0887-624x
%D 2013

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