First order activation‐ second order deactivation kinetics applied to the polymerization with supported Ziegler‐Natta catalysts

Abstract. X-ray studies revealed a strong trans-influence in titanium tetrachloride-ethyl benzoate complexes. From FTIR spectra, a very strong complexation is found in a 2:1 complex and in a surface complex on magnesium chloride supported Ziegler-Natta catalysts. In both cases the ester is proposed to be trans to a bridging chlorine. Key words:Ziegler-Natta, ethyl benzoate, titanium tetrachloride, transinfluence, complex.A recent important development in Ziegler-Natta catalysis is the development of the magnesium chloride supported highly active catalyst for the polymerization of olefins. The complexity and the excellent activity of the catalysts challenged our understanding of the system. We therefore initiated a basic research of the compounds which constitute the catalysts in order to obtain a more reliable comprehension of the structure of the active center, In this context the combination of IR-spectroscopy and single crystal X-ray scattering measurements proved to be a powerful tool to elucidate structural information of possible catalyst precursors.Accurate X-ray scattering measurements on single crystals of the 1:2 and 2:2 complexes between titanium tetrachloride and ethyl benzoate revealed important trends in bonding behaviour [1]. A significant transinfluence is observed. Terminal Ti-C1 bonds (2.31 A) trans to another terminal Ti-C1 are significantly longer than terminal Ti-C1 bonds (2.22--2.24 ,~) trans to an ester group or a bridging chlorine. A cis influence is also seen, as the ester complexation through carbonyl is enhanced by an increasing number of weakly bonded neighbours in the octahedral Ti-entity.

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“…This correlation indicates that the MgC12-surface bound TiCI4. EB-complex is a precursor of the active site of the catalyst [4,5].…”

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confidence: 99%

FTIR spectroscopy of ethyl benzoate-titanium tetrachloride complexes with application to supported Ziegler-Natta catalysts

et al. 1988

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“…Activation is the reaction through which a potential site is converted into a reactive vacant site. Several mechanisms are proposed in the literature . The present work considers the following four ways for the catalyst to become activated: by hydrogen, by co‐catalyst, by monomer, and spontaneous. …”

Section: General Catalytic Olefin Polymerization Kinetic Schemementioning

confidence: 99%

“…Site deactivation is the reaction step generally accepted as the explanation for the activity loss experienced during polymerization . Both occupied and vacant sites are assumed to deactivate: by hydrogen, by co‐catalyst, by by‐product, by poison, by monomer j , and spontaneous deactivation. …”

Section: General Catalytic Olefin Polymerization Kinetic Schemementioning

confidence: 99%

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Catalytic Olefin Polymerization Process Modeling: Multi‐Scale Approach and Modeling Guidelines for Micro‐Scale/Kinetic Modeling

Touloupidis

2014

Macro Reaction Engineering

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The scope of this work is to explain the multi‐scale polymerization process modeling framework, comprising of polymerization kinetics (micro‐scale), system thermodynamics (meso‐scale), and reactor performance (macro‐scale) as well as to present the methodology for developing a mathematical model for catalytic olefin polymerization. Guidelines for tuning the kinetic model parameters are proposed. This review aims to provide basic knowledge and understanding regarding catalytic olefin polymerization kinetics and offers the starter‐kit tools for developing similar works.

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Modelling Complex Kinetic Systems

Lemos

Costa

Lopes

et al. 2000

Combinatorial Catalysis and High Throughput Catalyst Design and Testing

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First order activation‐ second order deactivation kinetics applied to the polymerization with supported Ziegler‐Natta catalysts

Cited by 5 publications

References 10 publications

FTIR spectroscopy of ethyl benzoate-titanium tetrachloride complexes with application to supported Ziegler-Natta catalysts

FTIR spectroscopy of ethyl benzoate-titanium tetrachloride complexes with application to supported Ziegler-Natta catalysts

Catalytic Olefin Polymerization Process Modeling: Multi‐Scale Approach and Modeling Guidelines for Micro‐Scale/Kinetic Modeling

Modelling Complex Kinetic Systems

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