A Preparation Method for Well‐Defined Crystallites of Mgcl<sub>2</sub>‐Supported Ziegler‐Natta Catalysts and their Observation by AFM and SEM

Andoni, Adelaida; Chadwick, JC John; Niemantsverdriet, J.W.; Thüne, PC Peter

doi:10.1002/marc.200700222

Cited by 50 publications

(50 citation statements)

References 19 publications

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“…The function of the cocatalyst is well known to act as activator to reduce and alkylate the transition metal generating a Ti-C bond, which is responsible for the generation of active sites and essential for monomer insertion. [30][31][32] Alkyl aluminum can also scavenge impurities in the polymerization system. But too large amount of cocatalyst may lead to deactivation of the active sites through over-reduction of the active transition metal and also enhanced the chain transfer reaction to cocatalyst, which was not benefi cial for increasing the catalyst activity.…”

Section: Ethylene Homopolymerization and Characterization Of The Polymentioning

confidence: 99%

Vanadium Modification Effects on the (SiO₂/MgO/MgCl₂)•TiCl_xZiegler-Natta Polyethylene Catalyst

Wang

Cheng

et al. 2016

Macromol. React. Eng.

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MgCl 2 /TiCl 4 catalyst which was fi rst reported by Kashiwa [ 1 ] and Galli [ 2 ] independently in 1968. Anhydrous MgCl 2 was used as Mg-source, and excess amount of TiCl 4 removed the alcohol from MgCl 2 -alcoholate adduct and MgCl 2 was recrystallized simultaneously. This is a signifi cant innovation and greatly promotes the development of industrial polyolefi n processes. Another commercial MgCl 2 / TiCl 4 ZN catalyst was developed by Böhm, [ 3 ] and Mg(OEt) 2 as the Mg-source reacted with TiCl 4 directly to synthesize MgCl 2 support in situ. Later on, Union Carbide Corporation (UCC) also utilized anhydrous MgCl 2 as Mg-source and meanwhile introduced SiO 2 into the titanium-magnesium catalytic (TMC) system to develop a series of MgCl 2 /SiO 2 bi-supported ZN catalysts. The most famous MgCl 2 /SiO 2 ZN catalyst was M-1 catalyst and successfully applied in UNIPOL gas-phase polyethylene process. [ 4,5 ] Chamla [ 6 ] and Stevens [ 7 ] used alkyl magnesium (MgR 2 ) and Grignard reagents (RMgCl) as starting Mg-source, respectively, followed A novel vanadium-modifi ed (SiO 2 /MgO/MgCl 2 )·TiCl x Ziegler-Natta ethylene polymerization catalyst with much better catalytic performance is successfully developed. The catalyst is prepared by co-impregnation of aqueous solution of water-soluble magnesium and vanadium compounds on SiO 2 , and a supported thin layer of magnesium and vanadium oxides is formed over the surface of SiO 2 after high temperature calcination in dry air, followed by further reaction with titanium tetrachloride to synthesize the magnesium dichloride carrier in situ and to support the titanium species simultaneously. By characterization of the catalysts and the polymers and investigation of the polymerization behaviors, it is found that compared with the original (SiO 2 /MgO/MgCl 2 )·TiCl x ZN catalyst, the introduction of vanadium species induce improved catalytic performance with 27% higher activity, 48% higher hydrogen response, and 60% higher 1-hexene incorporation ability with better short chain branch distribution.

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Section: Ethylene Homopolymerization and Characterization Of The Polymentioning

confidence: 99%

Vanadium Modification Effects on the (SiO₂/MgO/MgCl₂)•TiCl_xZiegler-Natta Polyethylene Catalyst

Wang

Cheng

et al. 2016

Macromol. React. Eng.

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“…Due to the heterogeneous nature of the catalysts, the polymerization started at the surface of the PS‐supported catalyst 13. It is well known that the cocatalyst TEA reduced Ti 4+ to Ti 3+ in TiCl 4 and formed Ti‐C bond which is considerably active for ethylene polymerization 11…”

Section: Resultsmentioning

confidence: 99%

“…Interestingly, MgCl 2 ‐supported Ti‐based Ziegler–Natta catalyst shows amazingly high catalyst activity due to significant characteristics of MgCl 2 such as; similar ionic radii of Mg 2+ and Ti 4+ (0.65 and 0.68 ${\acute{\rm{\AA}}}$ , respectively), both belong to the same hexagonal system, highly porous structure, low electronegativity compared to titanium trichloride, and relatively chemical inertness 8, 9. The preparation method of the catalyst is also a key factor for catalyst activity 10–12…”

Section: Introductionmentioning

confidence: 99%

Polymer‐supported heterogeneous titanium‐based Ziegler‐Natta catalyst for ethylene polymerization

Kalita

Kamrupi

Pokhrel

et al. 2012

J of Applied Polymer Sci

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Reported here in, is the synthesis of polystyrene (PS)-supported Ziegler-Natta catalyst (PS-TiCl 4 ) by the reaction of PS and titanium tetrachloride (TiCl 4 ). PS was synthesized by emulsion polymerization using super critical CO 2 (sc-CO 2 ) as a medium. Three catalysts were synthesized by varying the TiCl 4 /PS weight ratio in hexane medium. The resulting catalysts were characterized by Fourier transformed-infrared spectroscopy, UV-visible spectroscopy, scanning electron microscope and energy dispersive X-ray detector, X-ray diffraction analysis. The acidity of the catalysts in an acetone/water solution was measured by pH meter. The thermogravimetric analysis reveals that catalysts are stable upto 150-180 C. Due to their higher degree of thermal stability these catalysts may potentially be used as a support in conventional Ziegler-Natta catalyst for ethylene polymerization. These catalysts also showed good storability and its overall catalytic productivity are found to be 3720 g PE/g Ti. The productivity of the catalysts also depended on the titanium concentration in the polymer matrix.

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“…The polymerization of ethylene proceeded in a heterogeneous system because the catalyst is dispersed in hexane. It is well known that the cocatalyst TEA reduces Ti 4 + to Ti 3 + in TiCl 4 , which is considerably active for ethylene polymerization 30…”

Section: Resultsmentioning

confidence: 99%

Poly(amic acid)‐Supported Heterogeneous Titanium‐Based Ziegler‐Natta Catalyst for Ethylene Polymerization in a Slurry Process

Kalita¹,

Konwer²,

Dolui³

2012

Adv Polym Technol

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ABSTRACT:The synthesis of a poly(amic acid) (PAA)-supported Ziegler-Natta catalyst (PAA-TiCl 4 ) by the reaction of PAA and titanium tetrachloride (TiCl 4 ) is reported. For ethylene polymerization, three catalysts were synthesized by varying the TiCl 4 /PAA weight ratio in a hexane medium. The resulting catalysts were characterized by Fourier-transformed infrared (FT-IR), ultraviolet (UV), scanning electron microscopy and energy dispersive x-ray detector (SEM-EDX), and x-ray diffraction analysis (XRD). The acidity of the catalysts in an acetone/water solution was measured by a pH meter. Thermogravimetric analysis reveals that catalysts are stable up to 110-125• C. Because of their higher degree of thermal stability, these catalysts may potentially be used as a support in a conventional Ziegler-Natta catalyst for ethylene polymerization. Furthermore, because of the extensive reaction between the functional groups of PAA and TiCl 4 , the chain structure of the PAA was destroyed. The newly synthesized catalysts showed good storability, and the Correspondence to: Swapan K. Dolui;

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A Preparation Method for Well‐Defined Crystallites of Mgcl₂‐Supported Ziegler‐Natta Catalysts and their Observation by AFM and SEM

Cited by 50 publications

References 19 publications

Vanadium Modification Effects on the (SiO₂/MgO/MgCl₂)•TiCl_xZiegler-Natta Polyethylene Catalyst

Vanadium Modification Effects on the (SiO₂/MgO/MgCl₂)•TiCl_xZiegler-Natta Polyethylene Catalyst

Polymer‐supported heterogeneous titanium‐based Ziegler‐Natta catalyst for ethylene polymerization

Poly(amic acid)‐Supported Heterogeneous Titanium‐Based Ziegler‐Natta Catalyst for Ethylene Polymerization in a Slurry Process

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A Preparation Method for Well‐Defined Crystallites of Mgcl2‐Supported Ziegler‐Natta Catalysts and their Observation by AFM and SEM

Cited by 50 publications

References 19 publications

Vanadium Modification Effects on the (SiO2/MgO/MgCl2)•TiClxZiegler-Natta Polyethylene Catalyst

Vanadium Modification Effects on the (SiO2/MgO/MgCl2)•TiClxZiegler-Natta Polyethylene Catalyst

Polymer‐supported heterogeneous titanium‐based Ziegler‐Natta catalyst for ethylene polymerization

Poly(amic acid)‐Supported Heterogeneous Titanium‐Based Ziegler‐Natta Catalyst for Ethylene Polymerization in a Slurry Process

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A Preparation Method for Well‐Defined Crystallites of Mgcl₂‐Supported Ziegler‐Natta Catalysts and their Observation by AFM and SEM

Vanadium Modification Effects on the (SiO₂/MgO/MgCl₂)•TiCl_xZiegler-Natta Polyethylene Catalyst

Vanadium Modification Effects on the (SiO₂/MgO/MgCl₂)•TiCl_xZiegler-Natta Polyethylene Catalyst