Chemical structure–stereospecificity relationship of internal donor in heterogeneous Ziegler–Natta catalyst for propylene polymerization by DFT and MM calculations

Lee, Jin Woo; Jo, Won Ho

doi:10.1016/j.jorganchem.2009.05.030

Cited by 36 publications

(22 citation statements)

References 47 publications

(68 reference statements)

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“…The results of Table S2 indicated a strong preference (∼11–15 kcal/mol) of DMDOMe for chelate binding to four-coordinated Mg sites (clu_27u_110) over pentacoordinated ones (clu_24u_104); this is in line with previous literature claims. 11 , 16 , 17 , 20 , 29 , 69 , 70 Moreover, conformer Do1 A binds stronger to both surfaces than conformer Do1 C (3–4 kcal/mol), as opposed to the relative stability of the isolated molecule (see Table S1 ).…”

Section: Resultsmentioning

confidence: 99%

Structural Characterization of Electron Donors in Ziegler–Natta Catalysts

et al. 2018

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Ziegler–Natta catalysis is a very important industrial process for the production of polyolefins. However, the catalysts are not well-understood at the molecular level. Yet, atomic-scale structural information is of pivotal importance for rational catalyst development. We applied a solid-state NMR/density functional theory tandem approach to gain detailed insight into the interactions between the catalysts’ support, MgCl2, and organic electron donors. Because of the heterogeneity of the samples, large line widths are observed in the carbon spectra. Despite this, good agreement between experimental and computational values was reached, and this shows that 1,3-diether based donors coordinate at (110) surface sites, while phthalates are less selective and coordinate at both (104) and (110) surface sites.

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Section: Resultsmentioning

confidence: 99%

Structural Characterization of Electron Donors in Ziegler–Natta Catalysts

et al. 2018

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“…There have been several theoretical studies on roles of electron donors such as malonates [17], succinates [18,19], 1,3-diethers [19][20][21], phthalates [22,23], methyl benzoates [14,24], ethyl benzoates [25,26], alkoxysilanes [27][28][29], and dibenzoyl sulfide in ZN-catalyzed PP polymerization [23]. Since salicylate compounds are the newest electron donors, no theoretical study on this topic has been reported.…”

Section: Sidmentioning

confidence: 99%

“…We have made a plot between the experimental PP activity and the adsorption energy (E ads ) of the five salicylate donors (SID-1-SID-5), together with that of diisobutyl phthalate (DIBP), as shown in Figure 4. Lee et al [20] found the relationship between adsorption energies of 1,3-diether donors to the MgCl2 surface and the isotacticity and the productivity of polypropylene. Moreover, Ratanasak et al [56] have studied the relation between the adsorption energies of various classes of electron donors to the catalyst surface and activities.…”

Section: Adsorption Energies Of Five Salicylate Donorsmentioning

confidence: 99%

Roles of Salicylate Donors in Enhancement of Productivity and Isotacticity of Ziegler–Natta Catalyzed Propylene Polymerization

2020

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Roles of internal salicylate donors (SID) in enhancing activity and stereoselectivity of Ziegler–Natta catalyzed propylene (PP) polymerization were examined using DFT calculations. Five salicylate donors were studied. The chelate mode is the preferred adsorption mode. The linear relationship (R2 = 0.96) between calculated adsorption energies (Eads) of five SIDs and the experimental PP activities was observed. Thus, the SID with the strongest adsorption energy will provide the highest activity in agreement with our previous studies. Compared with diisobutyl phthalate (DIBP), which is the industrial electron donor, SID has stronger Eads. The insertion step, which involves the π-complex formation (∆Eπ) and the insertion activation or intrinsic activation energy (Ea) for PP polymerization was also examined. The relation between ln(activity) and apparent activation energy (Ea(app)), which is ∆Eπ + Ea for the primary(1,2)-re insertion with R2 = 0.99, was observed. The salicylate donor also has a lower Ea(app) than that of DIBP. This explains the better catalytic performance of SID. Our results also demonstrated that the size and the type of hydrocarbon substituents play a key role in controlling stereoselectivity and activity. In addition, we found a good relationship between Eads and both intrinsic (Ea) and apparent (Ea(app)) activation energies of five salicylate donors with R2 of 0.90 and 0.97, respectively.

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“…There are other donors with two oxygen sites, each of which can donate electron density to the titanium center. [8,[10][11][12]57] These donors have not been considered in the current study because of the added computational complexity that is entailed for such donors because of their ability to coordinate not only to the titanium center but also to the MgCl 2 support in different conformations through the oxygen atoms. Studies with such bidentate donor cases will be taken up and reported soon.…”

Section: (B) Insertion and Termination Studies With The Mgcl 2 Modelmentioning

confidence: 99%

The Nature of the Active Site in Ziegler–Natta Olefin Polymerization Catalysis Systems – A Computational Investigation

2014

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Full quantum chemical calculations with density functional theory (DFT) show that a principal role of donors in ZieglerNatta (ZN) olefin polymerization catalysts is to coordinate to the metal center at the active sites on the MgCl 2 surface. Thereby, the behavior of the catalyst is modulated to favor insertion over termination and, thus, polymerization occurs. This is shown to be true for a range of different donors. The calculations indicate that active sites that feature anionic

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Chemical structure–stereospecificity relationship of internal donor in heterogeneous Ziegler–Natta catalyst for propylene polymerization by DFT and MM calculations

Cited by 36 publications

References 47 publications

Structural Characterization of Electron Donors in Ziegler–Natta Catalysts

Structural Characterization of Electron Donors in Ziegler–Natta Catalysts

Roles of Salicylate Donors in Enhancement of Productivity and Isotacticity of Ziegler–Natta Catalyzed Propylene Polymerization

The Nature of the Active Site in Ziegler–Natta Olefin Polymerization Catalysis Systems – A Computational Investigation

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