Effects of halogen ligands on 1,3-butadiene polymerization with cobalt dihalides and methylaluminoxane

Nath, Dilip Chandra Deb; Shiono, Takeshi; Ikeda, Tomiki

doi:10.1002/1521-3935(200206)203:9<1171::aid-macp1171>3.0.co;2-u

Cited by 21 publications

(10 citation statements)

References 7 publications

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“…If no other parameters operate the catalytic activity would be expected to increase in the order Cl < Br < I, since the geometry of the ene ‐hydrazone moiety is closer to that of the precursor species. This tendency is opposite to that reported for the effect of the halide on the polymerisation of 1,3‐butadiene by metal halides 29…”

Section: Resultscontrasting

confidence: 99%

Ethylene polymerisation by Ni–diphosphine azine complexes

Carvalho¹,

Čermák

Fernandes

et al. 2007

Polymer International

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The properties of [NiX(PR2CH2C(But)NNC(But)CH2PR2)]+ complexes (where X = Br, and R = cyclohexyl (Cy), isopropyl (Pri), tert‐butyl (But), phenyl (Ph); X = Cl or I, and R = cyclohexyl) as catalysts for the polymerisation of ethylene were evaluated with or without the co‐catalysts methylaluminoxane (MAO), diethylaluminium chloride, trimethylaluminium or tri(isobutyl)aluminium. Their efficiency depends on the characteristics of the halogen (X) and the R group of the diphosphine azine ligand. Bromide (X) strongly enhances the catalytic properties of the complexes within the R order Cy > Pri > Ph > But. Temperature, co‐catalyst ratio (Al/Ni) and complex concentration also influence the catalytic activity. The best results were obtained with [NiBr{PCy2CH2C(But)NNC(But)CH2PCy2}]Br activated by MAO (A = 25.8 kg (mol Ni)−1 bar−1 h−1). The polymers were characterised using NMR and differential scanning calorimetry as branched polyethylenes, the number of branches increasing with the temperature of polymerisation. The molecular weights of the polymers were estimated using NMR. A proposal for the catalyst active precursor is made on the basis of experimental data and molecular orbital calculations. Copyright © 2007 Society of Chemical Industry

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Section: Resultscontrasting

confidence: 99%

Ethylene polymerisation by Ni–diphosphine azine complexes

Carvalho¹,

Čermák

Fernandes

et al. 2007

Polymer International

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“…1 H NMR spectra of the homopolymers and copolymers are shown in Figure 1. Each peak is assigned according to the references 28–31, 33. It was impossible to determine the individual peak intensity of olefinic methine and vinyl protons of 1,3‐butadiene and isoprene because of the overlapping of those protons.…”

Section: Resultsmentioning

confidence: 99%

“…The activity and stereospecificity of the polymer solely depend on the types of cocatalysts and ligands attached to the cobalt species. We previously reported that the use of methylaluminoxane (MAO) instead of AlR 3 –ligand or AlR 2 Cl–Al X 3 ( X = Cl, Br, or I) with Co X 2 conducted the cis ‐1,4‐specific (99%) living polymerization of 1,3‐butadiene 28, 29. However, CoBr 2 (Ph 3 P) 2 –MAO30 gave predominantly 1,2‐sysndiotactic polybutadiene accompanied by a chain‐transfer reaction.…”

Section: Introductionmentioning

confidence: 99%

Copolymerization of 1,3‐butadiene and isoprene with cobalt dichloride/methylaluminoxane in the presence of triphenylphosphine

Nath

Shiono

Ikeda

2002

J. Polym. Sci. A Polym. Chem.

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The homopolymerization and copolymerization of 1,3‐butadiene and isoprene were achieved at 0 °C with cobalt dichloride in combination with methylaluminoxane and triphenylphosphine (Ph3P). For 1,3‐butadiene, highly cis‐specific and 1,2‐syndiospecific polymerization proceeded in the absence or presence of Ph3P, respectively, although the activity with Ph3P was much higher than that without Ph3P. Only a trace of the polymer was, however, obtained in isoprene polymerization when Ph3P had been added. For copolymerization, the polymer yield in the presence of Ph3P was about three times higher than that in its absence. Copolymerization in the presence of Ph3P was, therefore, investigated in more detail. Unimodal gel permeation chromatography elution curves with narrower polydispersity (weight‐average molecular weight/number‐average molecular weight ≈ 1.5) indicated that the propagation reaction proceeded by single‐site active species. Both the yield and molecular weight of the copolymer decreased with an increasing amount of isoprene in the feed, and this was followed by an increase in the isoprene content in the copolymer. The monomer reactivity ratios, r1 (1,3‐butadiene) and r2 (isoprene), were estimated to be 2.8 and 0.15, respectively. Although the 1,3‐butadiene content in the copolymer was strongly dependent on the comonomer composition in the feed, the ratio of 1,2‐inserted units to 1,4‐inserted units of 1,3‐butadiene was constant. Concerning the isoprene unit, the percentage of 1,2‐ and 3,4‐inserted units was increased at the expense of 1,4‐inserted units with an increasing isoprene content in the feed. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3086–3092, 2002

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“…Diverse ancillary ligands, such as N^N^N, N^N^O, N^C^N, N^N, O^P architectures were designed and synthesized. The corresponding Co(II) and Fe(II) complexes were further employed in (co‐)polymerization of dienes . Very recently, Huang and other groups reported Co(II) complexes for isoprene polymerization that offer high activity, precise control over the molecular weight and high cis ‐1,4‐alt‐3,4 microstructures .…”

Section: Introductionmentioning

confidence: 99%

Iminoimidazole‐based Co(II) and Fe(II) complexes: Syntheses, characterization, and catalytic behaviors for isoprene polymerization

Zhang

Zhu

Mahmood

et al. 2019

J. Polym. Sci. Part A: Polym. Chem.

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A stereoselectivity switchable polymerization of isoprene has been developed, which is catalyzed by iminoimidazole‐Co(II) and ‐Fe(II) complexes. The influence of substituents ranging from electron donating to the electron withdrawing on the iminoimidazole‐Co(II) and ‐Fe(II) catalysts is investigated for isoprene polymerization. Two sets of iminoimidazole‐Co(II) and ‐Fe(II) complexes have been prepared and fully characterized. X‐ray crystallography analysis reveals that the complexes Co1 and Fe1 adopt distorted tetrahedral geometries. In the presence of AlEt2Cl as co‐catalyst, all the Co(II) complexes are active and the catalytic activity is highly dependent on the molar ratio of Al/Co. All the Co(II) complexes exhibit higher activities at low Al/Co ratio. Compared with the Co(II) complexes, the Fe(II) complexes are essentially inactive under the identical condition. However, on activation with combination of AlEtCl2 and [Ph3C][B(C6F5)4], both Co(II) and Fe(II) complexes display high activities with good conversions of isoprene (up to >99%). Additionally, low molecular weight and high trans‐1,4‐unit (>96%) selectivity are characteristics of the resultant polyisoprene. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 767–775

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Effects of halogen ligands on 1,3-butadiene polymerization with cobalt dihalides and methylaluminoxane

Cited by 21 publications

References 7 publications

Ethylene polymerisation by Ni–diphosphine azine complexes

Ethylene polymerisation by Ni–diphosphine azine complexes

Copolymerization of 1,3‐butadiene and isoprene with cobalt dichloride/methylaluminoxane in the presence of triphenylphosphine

Iminoimidazole‐based Co(II) and Fe(II) complexes: Syntheses, characterization, and catalytic behaviors for isoprene polymerization

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