Preparation of MgCl2-supported Ziegler–Natta catalyst systems with new electron donors

Marques, Maria de Fátima Vieira; Cardoso, Renata da Silva; Silva, Micheli Galvão da

doi:10.1016/j.apcata.2009.11.027

Cited by 25 publications

(8 citation statements)

References 24 publications

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“…MgCl 2 -Z-Ns are composed of an internal electron donor (ID) added during catalyst preparation and an external electron donor (ED) added during polymerization simultaneously with alkylaluminium cocatalyst [1].…”

Section: Introductionmentioning

confidence: 99%

Effect of internal electron donor on the active center distribution in MgCl2-supported Ziegler–Natta catalyst

Zhang

et al. 2015

Catalysis Communications

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Section: Introductionmentioning

confidence: 99%

Effect of internal electron donor on the active center distribution in MgCl2-supported Ziegler–Natta catalyst

Zhang

et al. 2015

Catalysis Communications

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“…Since the discovery of TiCl 4 /Di/MgCl 2 –AlR 3 /De type propylene polymerization catalysts, great efforts have been paid to mechanistic studies on electron donor effects . The main role of Di has been proposed as to influence the support structure and control the amount and spacial distribution of TiCl 4 adsorbed on the surface of MgCl 2 crystallites .…”

Section: Introductionmentioning

confidence: 99%

Mechanism of internal and external electron donor effects on propylene polymerization with MgCl₂‐supported Ziegler–Natta catalyst: New evidences based on active center counting

Weng

Jiang

et al. 2018

J of Applied Polymer Sci

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Two TiCl 4 /Di/MgCl 2 type supported Ziegler-Natta catalysts were prepared by loading dibutylphthalate or dicyclopentyldimethoxysilane (DCPDMS) (internal donor, Di) and TiCl 4 on activated d-MgCl 2 in sequence, and a blank catalyst was prepared by loading TiCl 4 on the same d-MgCl 2 without adding Di. These catalysts have similar specific surface area and pore size distribution, thus form a suitable base for comparative studies. Propylene polymerization with the catalysts was conducted in n-heptane slurry using triethylaluminum (TEA) as cocatalyst, and the effects of Di as well as De (external donor, in this work it was DCPDMS) on the number of active centers, the distribution of active centers among three polypropylene (PP) fractions (isotactic, medium isotactic, and atactic PP chains), and chain propagation rate constants of the PP fractions were studied by counting the number of active centers in the PP fractions using a method based on selective quench-labeling of the propagation chains by 2-thiophenecarbonyl chloride. When De was not added in the polymerization, introducing a phthalate type Di in the catalyst evidently changed the active center distribution by enhancing the proportion of active centers producing isotactic PP (iPP) (C Ã i ), but scarcely changed reactivities of the three groups of active centers forming the three fractions. When the De was added in the polymerization system with TiCl 4 / phthalate/MgCl 2 catalyst, further shifting of active center distribution in favor of C Ã i took place, meanwhile reactivities of the three groups of active centers also remarkably changed in favor of C Ã i . Mutual effects of these changes led to overwhelming dominance of iPP production in the TiCl 4 /Di/MgCl 2 -TEA/De system (Di 5 phthalate, De 5 alkoxysilane). In contrast, though using alkoxysilane as Di also caused shifting of active center distribution in favor of C Ã i when De was not added, addition of alkoxysilane De caused reverse shifting of active center distribution in favor of those producing PP of lower stereoregularity. This unfavorable change largely counteracted the reactivity changes in favor of C Ã i caused by the De, rendering the catalytic system rather poor isospecificity. V C 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46605.

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“…Successful commercial classes of catalyst systems are based on monoester, diester, diether type of internal donors 9. Studies on other types on internal donors such as triethers,10 ethyl propionate,11 and mixed donors12, 13 are also reported. Donors have a profound impact on polymerization kinetics and product properties for example ethyl benzoate (monoester)‐based catalyst systems provide decay type of kinetics14, 15 and broad molecular weight distribution of the product where as diisobutyl phthalate (diester)‐based catalysts show steady‐state polymerization kinetics and produce polymer with narrower molecular weight distribution 16–18…”

Section: Introductionmentioning

confidence: 99%

Propylene polymerization using supported Ziegler–Natta catalyst systems with mixed donors

Makwana

Singala

Patankar

et al. 2011

J of Applied Polymer Sci

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Magnesium dichloride supported titanium catalyst incorporated with varying concentration of ethylbenzoate and diisobutyl phthalate together as internal donor are synthesized. The synthesized catalysts are characterized and compared with respect to composition, phase characteristics, crystallite size, and particle morphology. Performance of catalysts containing mixed donors is compared with the conventional single donor-based catalysts. The polymerization studies of the catalysts for propylene polymerization show dependence of polymerization kinetics on relative concentration of diisobutyl phthalate and ethylbenzoate. Molecular weight characteristics of polypropylene obtained from these catalysts are studied and correlated with the nature and concentration of donors present in the catalyst. Morphology replication from catalyst precursor to polymer is observed irrespective of the nature of donor being incorporated in the synthesized catalyst.

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Preparation of MgCl2-supported Ziegler–Natta catalyst systems with new electron donors

Cited by 25 publications

References 24 publications

Effect of internal electron donor on the active center distribution in MgCl2-supported Ziegler–Natta catalyst

Effect of internal electron donor on the active center distribution in MgCl2-supported Ziegler–Natta catalyst

Mechanism of internal and external electron donor effects on propylene polymerization with MgCl₂‐supported Ziegler–Natta catalyst: New evidences based on active center counting

Propylene polymerization using supported Ziegler–Natta catalyst systems with mixed donors

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Preparation of MgCl2-supported Ziegler–Natta catalyst systems with new electron donors

Cited by 25 publications

References 24 publications

Effect of internal electron donor on the active center distribution in MgCl2-supported Ziegler–Natta catalyst

Effect of internal electron donor on the active center distribution in MgCl2-supported Ziegler–Natta catalyst

Mechanism of internal and external electron donor effects on propylene polymerization with MgCl2‐supported Ziegler–Natta catalyst: New evidences based on active center counting

Propylene polymerization using supported Ziegler–Natta catalyst systems with mixed donors

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Mechanism of internal and external electron donor effects on propylene polymerization with MgCl₂‐supported Ziegler–Natta catalyst: New evidences based on active center counting