Determination of active centers in heterogeneous Ziegler‐Natta catalytic systems using carbon oxides

Mejzlík, Jiří; Lesná, Marie

doi:10.1002/macp.1977.021780127

Cited by 46 publications

(11 citation statements)

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“…The terminated polymer is radioactive when CH 3 O 3 H is used, while termination by 14 CH 3 OH yields a nonradioactive polymer [Burfield and Savariar, 1979;Zakharov et al, 1977]. Additional verification comes from experiments with 14 CO and 14 CO 2 [Mejzlik and Lesna, 1977].…”

Section: -4b Chemical Nature Of Propagating Speciesmentioning

confidence: 96%

Stereochemistry of Polymerization

Odian

2004

Principles of Polymerization

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Constitutional (formerly: structural) isomerism is encountered when polymers have the same overall chemical composition (i.e., same molecular formula) but differ in connectivitythe order in which the atoms are connected to each other. Polyacetaldehyde, poly(ethylene oxide), and poly(vinyl alcohol) are constitutional isomers. The first two polymers are CH CH 3 O C H 2 CH OH CH 2 CH 2 O n n Polyacetaldehyde Poly(ethylene oxide) Poly(vinyl alcohol) n obtained from isomeric monomers, acetaldehyde and ethylene oxide. The third is obtained by hydrolysis of poly(vinyl acetate) since vinyl alcohol does not exist (it is the enol form of acetaldehyde). Poly(methyl methacrylate) and poly(ethyl acrylate) are isomeric polymers CH 2 C CH 3 CO 2 CH 3 CH 2 CH CO 2 C 2 H 5 n n Poly (methyl methacrylate) Poly (ethyl acrylate) formed from isomeric monomers. Poly(E-caprolactam) and poly(hexamethylene adipamide) are isomeric even though the monomers are not isomeric. Similarly, the 1 : 1 copolymer of Principles of Polymerization, Fourth Edition.

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Section: -4b Chemical Nature Of Propagating Speciesmentioning

confidence: 96%

Stereochemistry of Polymerization

Odian

2004

Principles of Polymerization

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“…Zakharov et al, and others [105,188,189,326,352,353)) reacting selectively with the transition metal-carbon bonds (e.g. Ti-C) present only in the polymer chains still bound to active sites.…”

Section: Concentration and Location Of Catalytic Centres In Heterogenmentioning

confidence: 95%

“…Ti-C) present only in the polymer chains still bound to active sites. These methods too, however, provide results susceptible to criticism [326,353,354].…”

Section: Concentration and Location Of Catalytic Centres In Heterogenmentioning

confidence: 99%

Catalytic Olefin Polymerization

Pasquon

Giannini²

1984

Advances in Comparative and Environmental Physiology

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“…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%

“…In the past decades, several methods have been developed for the determination of active center concentration. [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.…”

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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Determination of active centers in heterogeneous Ziegler‐Natta catalytic systems using carbon oxides

Cited by 46 publications

References 7 publications

Stereochemistry of Polymerization

Stereochemistry of Polymerization

Catalytic Olefin Polymerization

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

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