Polymerization of ethylene using high-activity Ziegler-type catalysts: Active center determination

Marques, M. Manuel B.; Tait, Peter J. T.; Mejzlík, Jiří; Dias, Alberto R.

doi:10.1002/(sici)1099-0518(199803)36:4<573::aid-pola7>3.0.co;2-q

Cited by 27 publications

(17 citation statements)

References 6 publications

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“…The 14 CO radio-tagging method was first applied for heterogeneous Ziegler-Natta catalysts [70][71][72][73][74][75] and later extended to homogeneous α-olefin polymerization catalyst systems [38,65,76,77].…”

Section: Quench-labelling With 14 Comentioning

confidence: 99%

Quantification of active sites in single-site group 4 metal olefin polymerization catalysis

Desert

Carpentier

Kirillov

2019

Coordination Chemistry Reviews

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This review gives an overview of approaches and techniques used for the assessment of active sites count in homogeneous group 4 metal single-site α-olefin polymerization. The main advantages and limitations of these methods, in particular their ability to selectively and quantitatively discern the catalytic sites effectively at work, leaving aside dormant sites and other metal species not directly involved in propagation, as well as the results of their application onto some important single-site olefin polymerization catalyst systems are exemplified. The associated mechanistic information is of interest for engineering more efficient catalytic systems reluctant towards side reactions.

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Section: Quench-labelling With 14 Comentioning

confidence: 99%

Quantification of active sites in single-site group 4 metal olefin polymerization catalysis

Desert

Carpentier

Kirillov

2019

Coordination Chemistry Reviews

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“…[10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] The method using CH 3 OT as a quenching agent to tag the active centers has been proved to be a reliable one for both homogeneous and heterogeneous catalyst systems. 10,11 However, this method suffers from the limitation that only an average value of C p can be estimated. The methods based on quenching the propagating chains with 14 CO or CS 2 are complicated by possible reversibility of the quenching reactions and presence of side reactions.…”

Section: Introductionmentioning

confidence: 99%

“…The methods based on quenching the propagating chains with 14 CO or CS 2 are complicated by possible reversibility of the quenching reactions and presence of side reactions. 10,13,17,19,22,25 We have previously used acetyl chloride as a quenching agent to react with the active centers in heterogeneous Ziegler-Natta catalysts. 9,26,27 The reaction of acetyl chloride with TiCl 3 -AlR 3 catalyzed 1-octene polymerization system was found to be very fast and irreversible.…”

Section: Introductionmentioning

confidence: 99%

A new method of active center determination for olefin polymerization with supported Ziegler-Natta catalysts

Zhang

Fan

2010

Macromol. Res.

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A novel method based on a reaction between the growing polymer chain and cinnamoyl chloride (CC) was developed to determine the number of active centers (C p ) in olefin polymerization with supported Ziegler-Natta catalysts. The reaction of titanium-polymeryl bonds in the active centers of MgCl 2 /ID/TiCl 4 -AlR 3 type catalysts with CC was very fast at 20~80 o C. Cinnamoyl labeled polymer chains were formed, which were stable in the reaction system for at least 10 min when the CC/Al molar ratio was > 1. The number of active centers was determined by measuring the number of carbonyl groups in the polymer with the UV-vis method. The C p values of the 1-hexene polymerization systems with the addition of hydrogen were also measured.

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“…A large variety of solid materials were studied as support for the metallocene compounds, and some of them are magnesium dichloride, silica, alumina, zeolites (inorganic solids), or polymers (organic solids), etc. Magnesium dichloride was the best support for the conventional Ziegler–Natta catalyst, which is considered the fourth generation catalyst 3, 4. In addition, when the metallocenes are supported on magnesium dichloride, high catalytic activity is achieved,4–6 and also, in general, polymers with broad polydispersion are produced, indicating a multiplicity of active sites 7.…”

Section: Introductionmentioning

confidence: 99%

“…Magnesium dichloride was the best support for the conventional Ziegler–Natta catalyst, which is considered the fourth generation catalyst 3, 4. In addition, when the metallocenes are supported on magnesium dichloride, high catalytic activity is achieved,4–6 and also, in general, polymers with broad polydispersion are produced, indicating a multiplicity of active sites 7. Alumina is an inorganic oxide studied often as support for the metallocene catalysts and γ‐alumina is the type that is most frequently used 8–12.…”

Section: Introductionmentioning

confidence: 99%

The influence of the preparing conditions of SiO₂ supported Cp₂ZrCl₂ catalyst on ethylene polymerization

Marques

Conte

2002

J of Applied Polymer Sci

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ABSTRACT:In this work, ethylene was polymerized by using Cp 2 ZrCl 2 supported on silica pretreated with methylaluminoxane (MAO) as the catalyst system. The influence of the conditions for the preparation of the heterogeneous catalyst, such as temperature, washing method of the catalytic solid, MAO and metallocene concentration in the support treatment, time of MAO, and metallocene immobilization on the support, type of alkylaluminum used in the support pretreatment, and calcination temperature of the support were investigated. Aluminum and zirconium content fixed on the silica surface were determined by inductively coupled plasma emission spectroscopy. Polymer characteristics were determined by gel permeation chromatography and differential scanning calorimetry. According to the results, the activity of some supported catalysts were far higher than with the homogeneous system. Moreover, polyethylene with very high molecular weights were also obtained and with molecular weight distribution larger than those produced with the homogeneous precursor.

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Polymerization of ethylene using high-activity Ziegler-type catalysts: Active center determination

Cited by 27 publications

References 6 publications

Quantification of active sites in single-site group 4 metal olefin polymerization catalysis

Quantification of active sites in single-site group 4 metal olefin polymerization catalysis

A new method of active center determination for olefin polymerization with supported Ziegler-Natta catalysts

The influence of the preparing conditions of SiO₂ supported Cp₂ZrCl₂ catalyst on ethylene polymerization

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Polymerization of ethylene using high-activity Ziegler-type catalysts: Active center determination

Cited by 27 publications

References 6 publications

Quantification of active sites in single-site group 4 metal olefin polymerization catalysis

Quantification of active sites in single-site group 4 metal olefin polymerization catalysis

A new method of active center determination for olefin polymerization with supported Ziegler-Natta catalysts

The influence of the preparing conditions of SiO2 supported Cp2ZrCl2 catalyst on ethylene polymerization

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The influence of the preparing conditions of SiO₂ supported Cp₂ZrCl₂ catalyst on ethylene polymerization