Special Issue "Molecular Catalysis for Precise Olefin Polymerization"

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A special issue of Catalysts (ISSN 2073-4344).

Deadline for manuscript submissions: closed (25 December 2012)

Special Issue Editors

Guest Editor
Prof. Dr. Kotohiro Nomura (Website)

Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University (TMU), 1-1 Minami Osawa, Hachioji, Tokyo 192-0397, Japan
Phone: +81-42-6772547
Fax: +81 42 6772547
Interests: homogeneous catalysis; organometallics; catalysis and fine chemicals; precise olefin polymerization
Guest Editor
Prof. Dr. Minoru Terano (Website)

School of Material Science, Japan Advanced Institute of Science and Technology (JAIST), Asahidai 1-1, Tatsunokuchi, Ishikawa 923-1292, Japan
Interests: polymers (organic materials); surface science

Special Issue Information

Dear Colleagues,

Polyolefins, produced by metal catalyzed olefin coordination polymerization, are important commercial synthetic polymers in our daily life, and the market capacity still increases every year. Recently, considerable attention has been paid to produce new polymers with specified functions, properties which cannot be prepared by the conventional, ordinary catalysts and/or technology. New polymers can be prepared by incorporation of new comonomers (that cannot be incorporated by ordinary catalysts) in the copolymerization or some new methodology [living (co)polymerization, chain shuttling, tandem catalysts etc.]. It has been known that recent progress for design of the efficient transition metal complex catalysts that precisely control olefin coordination polymerization offers promising possibilities, and the related research attracts considerable attention not only in the field of catalysis, organometallic chemistry, but also in the field of polymer chemistry.

In this special issue, we would like to accept any manuscripts which are aimed to not only concerning design of new (homogeneous and heterogeneous) catalysts and synthesis of (co)polymers, but also the subject concerning polymerization methodologies and mechanistic studies on this good occasion. I personally believe that this should highly contribute to a progress in this research field.

I highly hope that we will be able to receive many submissions, and contribute as a good special issue in this Journal.

Prof. Dr. Kotohiro Nomura
Prof. Dr. Minoru Terano
Guest Editors

Keywords

  • catalyst design
  • homogeneous/heterogeneous catalysts
  • polymerization
  • reaction mechanism
  • catalyst synthesis/preparation
  • polymer synthesis

Published Papers (7 papers)

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Research

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Open AccessArticle Phosphine-Thiophenolate Half-Titanocene Chlorides: Synthesis, Structure, and Their Application in Ethylene (Co-)Polymerization
Catalysts 2013, 3(1), 261-275; doi:10.3390/catal3010261
Received: 28 December 2012 / Revised: 8 February 2013 / Accepted: 17 February 2013 / Published: 6 March 2013
Cited by 3 | PDF Full-text (369 KB) | HTML Full-text | XML Full-text
Abstract
A series of novel half-titanocene complexes CpTiCl2[S-2-R-6-(PPh2)C6H3] (Cp = C5H5, 2a, R = H; 2b, R = Ph; 2c, R = SiMe3) have been synthesized [...] Read more.
A series of novel half-titanocene complexes CpTiCl2[S-2-R-6-(PPh2)C6H3] (Cp = C5H5, 2a, R = H; 2b, R = Ph; 2c, R = SiMe3) have been synthesized by treating CpTiCl3 with the sodium of the ligands, 2-R-6-(PPh2)C6H3SNa, which were prepared by the corresponding ligands and NaH. These complexes have been characterized by 1H, 13C and 31P NMR as well as elemental analyses. Structures for 2a–b were further confirmed by X-ray crystallography. Complexes 2a–b adopt five-coordinate, distorted square-pyramid geometry around the titanium center, in which the equatorial positions are occupied by sulfur and phosphorus atoms of the chelating phosphine-thiophenolate and two chlorine atoms, and the cyclopentadienyl ring is coordinated on the axial position. The complexes 2a–c were investigated as the catalysts for ethylene polymerization and copolymerization of ethylene with norbornene in the presence of MMAO or Ph3CB(C6F5)4/iBu3Al as the cocatalyst. All complexes exhibited low to moderate activities towards homopolymerization of ethylene. However, they displayed moderate to high activities towards copolymerization of ethylene with norbornene. Full article
(This article belongs to the Special Issue Molecular Catalysis for Precise Olefin Polymerization)
Open AccessArticle A Comparative Study on the Homo-, Co- and Ter-Polymerization Using Ethylene, 1-Decene and p-Methylstyrene
Catalysts 2013, 3(1), 176-188; doi:10.3390/catal3010176
Received: 21 December 2012 / Revised: 1 February 2013 / Accepted: 7 February 2013 / Published: 22 February 2013
PDF Full-text (571 KB) | HTML Full-text | XML Full-text
Abstract
We synthesized polyethylene (PE), poly(ethylene-co-1-decene), poly(ethylene-co-p-methylstyrene) and poly(ethylene-ter-1-decene-ter-p-methystyrene) using a rac-Et(Ind)2ZrCl2 metallocene catalyst and a methylaluminoxane cocatalyst system. The materials were characterized using nuclear magnetic resonance [...] Read more.
We synthesized polyethylene (PE), poly(ethylene-co-1-decene), poly(ethylene-co-p-methylstyrene) and poly(ethylene-ter-1-decene-ter-p-methystyrene) using a rac-Et(Ind)2ZrCl2 metallocene catalyst and a methylaluminoxane cocatalyst system. The materials were characterized using nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy. We compared and studied the kinetics, thermal properties and mechanical ones of these polymers. Tg was related to the amorphous phase of the polymers, whereas the tensile strength and storage modulus (E’) were related to the crystalline phase. We also found that PE has the highest crystallinity through differential scanning calorimetry and wide-angle X-ray scattering analysis. The polymerization rates of poly(ethylene-co-1-decene) and poly(ethylene-ter-1-decene-ter-p-methystyrene) were always higher than that of polyethylene. Full article
(This article belongs to the Special Issue Molecular Catalysis for Precise Olefin Polymerization)
Open AccessArticle Precise Active Site Analysis for TiCl3/MgCl2 Ziegler-Natta Model Catalyst Based on Fractionation and Statistical Methods
Catalysts 2013, 3(1), 137-147; doi:10.3390/catal3010137
Received: 17 December 2012 / Revised: 30 January 2013 / Accepted: 1 February 2013 / Published: 7 February 2013
Cited by 4 | PDF Full-text (573 KB) | HTML Full-text | XML Full-text
Abstract
In heterogeneous Ziegler-Natta catalysts for olefin polymerization, isolation of a single type of active sites is a kind of ambition, which would solve long-standing questions on the relationship between active site and polymer structures. In this paper, polypropylene produced by TiCl3 [...] Read more.
In heterogeneous Ziegler-Natta catalysts for olefin polymerization, isolation of a single type of active sites is a kind of ambition, which would solve long-standing questions on the relationship between active site and polymer structures. In this paper, polypropylene produced by TiCl3/MgCl2 model catalysts with minimum Ti heterogeneity was analyzed by combined solvent fractionation and the two-site statistical model. We found that the active sites of the model catalysts were classified into only three types, whose proportions were dependent on the Ti dispersion state. The addition of external donors not only newly formed highly isospecific sites, but also altered the stereochemical nature of the other active sites. Full article
(This article belongs to the Special Issue Molecular Catalysis for Precise Olefin Polymerization)
Open AccessArticle Ethylene Polymerization Using (Imino)vanadium(V) Dichloride Complexes Containing (Anilido)methyl-pyridine, -quinoline Ligands–Halogenated Al Alkyls Catalyst Systems
Catalysts 2013, 3(1), 148-156; doi:10.3390/catal3010148
Received: 25 December 2012 / Revised: 29 January 2013 / Accepted: 30 January 2013 / Published: 7 February 2013
Cited by 3 | PDF Full-text (251 KB) | HTML Full-text | XML Full-text
Abstract
The effect of ligand and Al cocatalysts in ethylene polymerization, using V(N-1-adamantyl)Cl2(L) [L = 2-(2,6-Me2C6H3)NCH2(C9H6N), 8-(2,6-Me2C6H3)NCH2(C9H [...] Read more.
The effect of ligand and Al cocatalysts in ethylene polymerization, using V(N-1-adamantyl)Cl2(L) [L = 2-(2,6-Me2C6H3)NCH2(C9H6N), 8-(2,6-Me2C6H3)NCH2(C9H6N)] and V(N-2-MeC6H3)Cl2[2-(2,6-R'2C6H3)NCH2(C5H4N)] (R' = Me, iPr), has been explored. The reaction products in the presence of Et2AlCl or Me2AlCl cocatalyst were polyethylene whereas the reaction product of the 2-methylphenylimido analogues in the presence of MAO cocatalyst was 1-butene with high selectivity, suggesting that the catalyst/cocatalyst nuclearity effect plays a role in this catalysis. Full article
(This article belongs to the Special Issue Molecular Catalysis for Precise Olefin Polymerization)
Open AccessArticle Preparation of Thiophene-Fused and Tetrahydroquinoline-Linked Cyclopentadienyl Titanium Complexes for Ethylene/α-Olefin Copolymerization
Catalysts 2013, 3(1), 104-124; doi:10.3390/catal3010104
Received: 17 December 2012 / Revised: 25 January 2013 / Accepted: 29 January 2013 / Published: 6 February 2013
Cited by 3 | PDF Full-text (483 KB) | HTML Full-text | XML Full-text
Abstract
A synthetic scheme was developed for the large-scale preparation of a dimethylthiophene-fused and tetrahydroquinaldine-linked dimethylcyclopentadienyl titanium complex (2), which is a high-performance homogeneous Ziegler catalyst. 2,3,4,5-Tetramethyl-4,5-dihydrocyclopenta[b]thiophen-6-one was prepared without chromatography purification on the 40-g scale in a laboratory [...] Read more.
A synthetic scheme was developed for the large-scale preparation of a dimethylthiophene-fused and tetrahydroquinaldine-linked dimethylcyclopentadienyl titanium complex (2), which is a high-performance homogeneous Ziegler catalyst. 2,3,4,5-Tetramethyl-4,5-dihydrocyclopenta[b]thiophen-6-one was prepared without chromatography purification on the 40-g scale in a laboratory setting, from which the ligand precursor for 2 was obtained in 65% yield on a 50-g scale in a one-pot without the need for chromatography purification. Metallation was achieved in a high yield (78%) through reaction of the dilithiated compound with TiCl4. Many derivatives were prepared by employing the same synthetic scheme as applied for 2. Among them, the titanium complex prepared from 2-methyl-4,5-dimethyl-6-(2-n-butyl-2,3,4,5-tetrahydroquinolin-8-yl)-4H-cyclopenta[b]thiophene exhibited an exceptionally high activity. Under commercially relevant high-temperature polymerization conditions (160 °C), this compound showed a higher activity than 2 (126 × 106 g/molTi∙h versus 72 × 106 g/molTi∙h), albeit with the formation of a polymer of slightly lower molecular weight (Mw, 159,000 versus 218,000) and with a slightly lower 1-octene content (9.3 mol% versus 12 mol%). Full article
(This article belongs to the Special Issue Molecular Catalysis for Precise Olefin Polymerization)
Figures

Open AccessArticle Oligomerization of Ethylene to Produce Linear α-Olefins Using Heterogeneous Catalyst Prepared by Immobilization of α-Diiminenickel(II) Complex into Fluorotetrasilicic Mica Interlayer
Catalysts 2013, 3(1), 125-136; doi:10.3390/catal3010125
Received: 13 December 2012 / Revised: 29 January 2013 / Accepted: 29 January 2013 / Published: 6 February 2013
Cited by 3 | PDF Full-text (327 KB) | HTML Full-text | XML Full-text
Abstract
Heterogeneous catalysts for production of linear α-olefins from ethylene were prepared by the direct reaction of the α-diimine ligand [L: R-N=C(R')-C(R')=N-R; R' = Me and R = 2,6-Me2Ph (L5), 2,5-Me2Ph (L1), 2-MePh [...] Read more.
Heterogeneous catalysts for production of linear α-olefins from ethylene were prepared by the direct reaction of the α-diimine ligand [L: R-N=C(R')-C(R')=N-R; R' = Me and R = 2,6-Me2Ph (L5), 2,5-Me2Ph (L1), 2-MePh (L2), or Ph (L3); R' = 1,8-naphth-diyl and R = Ph (L4)] and Ni2+ ion-exchanged fluorotetrasilicic mica. Only high molecular weight polyethylene was obtained in the reaction using the L5/Ni2+-Mica procatalyst activated by AlEt3 (TEA) as an activator, whereas the TEA-activated L1- and L2/Ni2+-Mica procatalysts afforded a mixture of a large amount of low-molecular weight polyethylene and a small amount of oligomers having 4-22 carbons. The procatalyst consisting of Ni2+-Mica and the L3 ligand that possesses non-substituted phenyl groups on the iminonitrogen atoms effectively promoted the oligomerization of ethylene after its activation with TEA, resulting in the fact that the ethylene oligomers were produced with a moderate catalytic activity (101 g-ethylene g-cat−1 h−1 at 0.7 MPa-ethylene) in the presence of TEA. When the backbone was varied from the butane moiety (L3) to acenaphthene (L4), the solid product dramatically increased. The weight percentage of the oligomers in the total products increased with the increasing reaction temperature; however, an insignificant increase in the oligomers was observed when the ethylene pressure was decreased. Full article
(This article belongs to the Special Issue Molecular Catalysis for Precise Olefin Polymerization)

Review

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Open AccessReview Half-Titanocenes Containing Anionic Ancillary Donor Ligands: Effective Catalyst Precursors for Ethylene/Styrene Copolymerization
Catalysts 2013, 3(1), 157-175; doi:10.3390/catal3010157
Received: 25 December 2012 / Revised: 21 January 2013 / Accepted: 25 January 2013 / Published: 18 February 2013
Cited by 4 | PDF Full-text (476 KB) | HTML Full-text | XML Full-text
Abstract
This review summarizes recent results for ethylene/styrene copolymerization using half-titanocenes containing anionic donor ligands, Cp’TiX2(Y) (X = halogen, alkyl; Y = aryloxo, ketimide etc.)–cocatalyst systems. The product composition, the styrene incorporation and microstructures in the resultant copolymers are highly [...] Read more.
This review summarizes recent results for ethylene/styrene copolymerization using half-titanocenes containing anionic donor ligands, Cp’TiX2(Y) (X = halogen, alkyl; Y = aryloxo, ketimide etc.)–cocatalyst systems. The product composition, the styrene incorporation and microstructures in the resultant copolymers are highly influenced by the anionic donor employed. A methodology for an exclusive synthesis of the copolymers even under high temperature and high styrene concentrations has been introduced on the basis of a proposed catalytically-active species in this catalysis. Full article
(This article belongs to the Special Issue Molecular Catalysis for Precise Olefin Polymerization)

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