Effect of the pore architecture of Ziegler-Natta catalyst on its behavior in propylene/1-hexene copolymerization

Shams, Arash; Mehdizadeh, Mohammadreza; Teimoury, Hamidreza; Emami, Mehrsa; Mirmohammadi, Seyed Amin; Sadjadi, Samahe; Bardají, Eduard; Poater, Albert; Bahri‐Laleh, Naeimeh

doi:10.1016/j.jiec.2022.09.026

Cited by 28 publications

(18 citation statements)

References 54 publications

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“…The catalytic activity of the two-component Ziegler-Natta catalyst is unstable, so it is necessary to add the third component of the ligand to improve the catalytic activity and stability of the catalyst, and this electron donor is also called the activator of the catalytic system. According to the mechanism analysis of the Ziegler-Natta catalytic system, it can be seen that the catalytic system is multi-active center, [22,[37][38][39][40] and its reaction selectivity is particularly important. Only when the reaction selectivity range is narrow, the polymerization reaction catalyzed by it can be stable.…”

Section: Resultsmentioning

confidence: 99%

Effect of Ligand Steric Hindrance on Catalytic Polymerization of Cycloolefin Polymer (COP)

Zhang

Fang

Huang³

et al. 2023

ChemistrySelect

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The traditional two‐component Ziegler‐Natta catalyst has low catalytic activity when initiating ring‐opening metathesis polymerization (ROMP) and is unstable and easy to generate polymerization gels. Therefore, it is necessary to add a third group of ligands with appropriate steric hindrance to improve the catalytic activity of the catalyst. The effects of ligands′ steric hindrance and other reaction conditions on the catalytic activity of tungsten hexachloride (WCl6) as catalyst and aluminum triethyl (AlEt3) as co‐catalyst were investigated. The results showed that the size of the ligands′ steric hindrance affected the catalytic activity of ROMP, and the small steric hindrance caused the polymerization rate to be too fast, which was easy to produce gels, and when the steric hindrance of the ligands was too large, its solubility was not good, which was not conducive to the normal polymerization. When stearyl alcohol was selected as the ligand, the highest catalytic activity was 3123 mol cycloolefin polymer (COP)/mol W, and the reaction speed of polymerization was also the fastest and the complete transformation only needed 30 min when the ligand/W was 25. It was found that the polymerization reaction was stable without gels and the obtained polymer molecular weight was appropriate, 17.8 kDa, under the conditions of Al/W=80, reaction temperature 60 °C, monomer concentration 10 w/v %, catalyst/monomer 5*10−4 : 1, chain transfer agent/monomer 0.005 : 1.

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Section: Resultsmentioning

confidence: 99%

Effect of Ligand Steric Hindrance on Catalytic Polymerization of Cycloolefin Polymer (COP)

Zhang

Fang

Huang³

et al. 2023

ChemistrySelect

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“…After nearly 70 years of development, current Ziegler–Natta catalysts are mostly heterogeneous catalysts that load metal salts on macroporous supports (such as TiCl 4 /MgCl 2 ). Researchers (Shams et al, 2022) have reported the high activity of this catalyst in propylene/1-hexene copolymerization.…”

Section: Polymer Hydrogenation Catalystsmentioning

confidence: 99%

Advances in the Catalytic Hydrogenation and Properties of Unsaturated Polymers

Yan

Cao

2023

Macromolecules

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Polymer reaction and performance improvement are one of the important contents in the field of polymer materials science and engineering, in which polymer catalytic hydrogenation is an important part of polymer reaction. We reviewed the research achievements on polymer hydrogenation over the past 70 years and studied the mechanism of the hydrogenation reaction from the aspects of performance changes before and after polymer hydrogenation, the catalyst preparation/structure−activity relationship, and polymer hydrogenation kinetics. We pointed out the difficulty in separation and unsatisfactory high-temperature adaptability of traditional homogeneous catalysts and first proposed four effects affecting traditional heterogeneous polymer hydrogenation: scale effect, conformation effect, viscosity effect, and adhesion effect. Based on the structure−activity relationship of polymers, we put forward the application direction of hydrogenated polymers at present. We found that using a new kind of nanometal catalyst (Pd/CNTs@FN) as hydrogenation catalyst can effectively reduce or eliminate the negative effects of these four effects on the polymer hydrogenation reaction, and it is easy to separate from the reaction system. The addition of CNTs can effectively increase the specific surface area of the catalyst and strengthen the interaction between reactants and catalyst. Subsequent research should focus on designing the multiscale structure and improving low-temperature activity of the catalyst, reducing process cost, and using green and efficient separation methods to eliminate adverse effects, create a green and efficient polymer reaction system, accelerate the industrialization of polymer hydrogenation process, and provide theoretical guidance for the research and development of new polymer materials.

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“…In order to incorporate various functions into a single material, the design should have multidimensional character. On the other hand, this multidimensionality leads to the complexation of structure‐properties relationships, especially in catalytic reactions 7–9 …”

Section: Introductionmentioning

confidence: 99%

“…On the other hand, this multidimensionality leads to the complexation of structure-properties relationships, especially in catalytic reactions. [7][8][9] High density and linear low-density polyethylene, HDPE, and LLDPE constitute the highest share of synthetic polymers market in the world. 10,11 These polymers are commercially produced mostly by heterogeneous Ziegler Natta catalysts.…”

Section: Introductionmentioning

confidence: 99%

Effect of adduct synthesis parameters on the ethylene polymerization kinetics of Ziegler Natta catalysts

Nouri-Ahangarani

Bahri‐Laleh

Abedini

et al. 2023

J of Applied Polymer Sci

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Here, it is aimed to clarify the structure-performance relationship in MgCl 2 based Ziegler Natta catalysts toward ethylene polymerizations. In this regard, 11 different adduct precursors were prepared through industrially appreciated melt quenching method employing various: (i) reaction times for dissolving magnesium chloride inside ethanol; (ii) ethanol/MgCl 2 molar ratios in the feed; (iii) heating rates during thermal dealcoholation; (iv) N 2 flows during thermal dealcoholation and (v) alcohol content after thermal dealcoholation. Among the studied parameters, heating rate and N 2 flow during thermal dealcoholation have the most pronounced effect on the porosity and particle size of the resulted adducts. Related Ziegler Natta catalysts were subsequently employed in ethylene polymerizations. According to the kinetic curves, catalyst productivity and form of kinetic curve (as decay or build-up type) can be precisely tailored by proper choosing of the mentioned variables during adduct synthesis. Microstructure analysis of the prepared polyethylenes reveals that alcohol content in the final adduct has the most significant effect on the H 2 response, in terms of molar mass and its distribution, of the related Ziegler Natta catalysts. The overall results help polyethylene producers in choosing proper reaction conditions during adduct synthesis for the production of different polymer grades, when productivity or H 2 response is targeted.

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Effect of the pore architecture of Ziegler-Natta catalyst on its behavior in propylene/1-hexene copolymerization

Cited by 28 publications

References 54 publications

Effect of Ligand Steric Hindrance on Catalytic Polymerization of Cycloolefin Polymer (COP)

Effect of Ligand Steric Hindrance on Catalytic Polymerization of Cycloolefin Polymer (COP)

Advances in the Catalytic Hydrogenation and Properties of Unsaturated Polymers

Effect of adduct synthesis parameters on the ethylene polymerization kinetics of Ziegler Natta catalysts

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