Magnesium chloride supported metallocene catalysts in olefin polymerizations

Conte, Anunciata; Marques, Maria de Fátima Vieira

doi:10.1016/s0014-3057(01)00071-4

Cited by 7 publications

(5 citation statements)

References 7 publications

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“…Immobilization of Cp 2 ZrCl 2 was carried out with and without first pretreating the support with MAO, which was also used as cocatalyst in polymerization. 427 Narrow molecular weight distribution was obtained, but catalyst decay during polymerization was apparent, similar to homogeneous polymerization. Very low activity was obtained when a bulkier zirconocene, Et-(Flu) 2 ZrCl 2 , was used.…”

Section: Magnesium Chloridementioning

confidence: 78%

“…MgCl 2 -supported metallocenes have also been prepared using the product of ball milling magnesium chloride with ethyl benzoate, one of the earliest methods used in the preparation of activated MgCl 2 as a support for Ziegler−Natta catalysts. Immobilization of Cp 2 ZrCl 2 was carried out with and without first pretreating the support with MAO, which was also used as cocatalyst in polymerization . Narrow molecular weight distribution was obtained, but catalyst decay during polymerization was apparent, similar to homogeneous polymerization.…”

Section: Magnesium Chloridementioning

confidence: 99%

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“Bound but Not Gagged”Immobilizing Single-Site α-Olefin Polymerization Catalysts

et al. 2005

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Section: Magnesium Chloridementioning

confidence: 78%

Section: Magnesium Chloridementioning

confidence: 99%

“Bound but Not Gagged”Immobilizing Single-Site α-Olefin Polymerization Catalysts

et al. 2005

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“…[15][16][17][18] The majority of these researches studied ethylene (co)polymerization while only a few reported for propylene polymerization. [19][20][21][22][23][24][25][26][27][28][29][30] For example, Satyanarayana and Sivaram [ 19 ] reported that active species derived from titanocene dichloride were stabilized by MgCl 2 during ethylene polymerization. Kaminaka and Soga [ 20 ] reported that a zirconocene catalyst supported on MgCl 2 pre-treated with alkylaluminum was activatable with alkylaluminum, and gave polydisperse polypropylene.…”

Section: Physical Methodsmentioning

confidence: 99%

Dual‐Active‐Site Nature of Magnesium Dichloride‐Supported Cyclopentadienyl Titanium Chloride Catalysts Switched by an Activator in Propylene Polymerization

Goto

Taniike

Terano

2013

Macro Chemistry & Physics

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MgCl 2 -supported metallocene catalysts often show peculiar catalytic aspects, which are partially similar to both non-supported complexes and traditional Ziegler-Natta catalysts. In this study, the active-site natures of various MgCl 2 -supported cyclopentadienyl Ti chloride catalysts are systematically investigated and compared with traditional catalysts in propylene polymerization. The supported titanocene catalysts offer both metallocene-type and ZieglerNatta-type active-site natures according to the details of the preparation and the activation procedures. The observed dualactive-site natures are plausibly correlated with the valence and charge states of the Ti center. concentrated stereoerrors and high regioregularity, generally resulting in a higher melting point. [ 1 ] On the other hand, typical ansa-metallocene catalysts produce monodisperse polypropylene with stereoerrors randomly distributed over the backbone as well as lower regioregularity. [ 2 ] Industrial heterogeneous Ziegler-Natta catalysts consist of TiCl 4 supported on MgCl 2 combined with Lewisbase compounds (called as donors) and trialkylaluminum. Their active species are regarded as neutral Ti(III)-alkyl species, situated in a pseudo-octahedral symmetry. It is well accepted within a three-site model that the isospecifi city is originated from ligands coordinated at metal ions adjacent to an active Ti center. [ 3 , 4 ] Further details on the active sites such as the placement of TiCl 4 on MgCl 2 surfaces and the identity of stereo-regulating ligands are still ambiguous, mainly due to diffi culties in the characterization of active sites and the polydispersity itself in polymer structures. Consequently, the structures of isotactic polypropylene have been empirically controlled in its industrial production, based on different combinations of internal and external donors.

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“…A great number of publications reported inorganic and organic porous materials as metallocene supports. Inorganic supports, represented by SiO 2 , Al 2 O 3 and zeolite with hard surface and massive acidic groups, may cause a problem of deactivation and high cocatalyst costs [8][9][10][11][12][13][14][15][16]. In comparison, kinds of soft organic supports such as polystyrene, polysiloxane and POPs [17][18][19][20][21][22][23] provide an analogous environment to homogeneous polymerization and could be used without complex pre-treatment [24].…”

Section: Introductionmentioning

confidence: 99%

Ionic Liquid-Modified Porous Organic Polymers as Efficient Metallocene Catalyst Supports

et al. 2022

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Porous organic polymers (POPs) are widely used in various areas such as adsorption, separation and catalysis. In the present work, ionic liquid-modified porous organic polymers (IL-POPs) synthesized by dispersion polymerization were applied to immobilize metallocene catalysts for olefin polymerization. The prepared IL-POPs were characterized by Fourier transform infrared spectrometer (FT-IR), nitrogen sorption porosimetry, X-ray photoelectron spectroscopy (XPS), thermal gravimetric analysis (TGA), inductively coupled plasma atomic emission spectrometer (ICP) and scanning electron microscope (SEM) analysis. The IL-POPs obtained pores with surface specific area (SSA) ranging from 16.9 m2/g to 561.8 m2/g, and total pore volume (TPV) ranging from 0.08 cm3/g to 0.71 cm3/g. The supported catalysts Zr/MAO@IL-POPs exhibit great activity (3700 kg PE/mol·Zr·bar·h) in ethylene polymerization, and the GPC-IR results show that the polyethylene has narrow molecular weight distribution (2.2 to 2.8). The DSC results show that the melting point of prepared polyethylene was as high as 138 °C, and the TREF analysis results indicate that they have similar chemical composition distribution with elution temperature at 100.5–100.7 °C.

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Magnesium chloride supported metallocene catalysts in olefin polymerizations

Cited by 7 publications

References 7 publications

“Bound but Not Gagged”Immobilizing Single-Site α-Olefin Polymerization Catalysts

“Bound but Not Gagged”Immobilizing Single-Site α-Olefin Polymerization Catalysts

Dual‐Active‐Site Nature of Magnesium Dichloride‐Supported Cyclopentadienyl Titanium Chloride Catalysts Switched by an Activator in Propylene Polymerization

Ionic Liquid-Modified Porous Organic Polymers as Efficient Metallocene Catalyst Supports

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