A Methodology for Estimating Kinetic Parameters and Reactivity Ratios of Multi‐site Type Catalysts Using Polymerization, Fractionation, and Spectroscopic Techniques

Touloupidis, Vasileios; Albrecht, A. C.; Soares, João B. P.

doi:10.1002/mren.201700056

Cited by 32 publications

(5 citation statements)

References 31 publications

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“…The general kinetic scheme proposed by G. Natta [39] for the propylene polymerization over Ziegler-Natta catalysts (Scheme 1) is usually used for the kinetic analysis of catalytic polymerization of olefins. This scheme has been discussed in many papers [39][40][41][42][43][44][45][46][47][48][49][50][51][52][53].…”

Section: Resultsmentioning

confidence: 99%

Heterogeneity of Active Sites in the Polymer Chain Transfer Reactions at Olefin Polymerization over Multisite Supported Ziegler-Natta Catalysts

Matsko,

Zakharov

2023

Polymers

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In this review, we summarize and discuss our experimental data published in a number of papers on the transfer reactions of polymer chains in the polymerization of ethylene, propylene, and hexene-1, and the copolymerization of ethylene with α-olefins over multisite supported titanium–magnesium catalysts (TMC). Three groups of transfer reactions are discussed in the review: (1) transfer reactions with AlEt3 cocatalyst, (2) transfer reactions with hydrogen, and (3) transfer reactions with participation of α-olefins in the case of ethylene copolymerization with α-olefins. We have found polymerization conditions where it is possible to observe heterogeneity of active sites of TMC for all three groups of the indicated reactions. It is shown that (1) the transfer reaction with AlEt3 proceeds with higher reactivity on the active sites that produce polymers with low molecular weight; (2) the transfer reaction with hydrogen, in the case of α-olefin polymerization and copolymerization of ethylene with α-olefins, proceeds with higher reactivity on the active sites which produce polymers with high molecular weight; (3) the transfer reaction with α-olefins proceed with higher reactivity on the active sites that produce high molecular weight polymers.

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Section: Resultsmentioning

confidence: 99%

Heterogeneity of Active Sites in the Polymer Chain Transfer Reactions at Olefin Polymerization over Multisite Supported Ziegler-Natta Catalysts

Matsko,

Zakharov

2023

Polymers

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“…The MWD of the polymer generated by a single-site catalyst conforms to the Schulz–Flory distribution. , Several methodologies for the kinetic parameter estimation and deconvolution have been proposed. Touloupidis introduced an effective methodology capable of estimating all pertinent parameters and reverse engineer experimental results. Feng , carried out parameter estimation centered on a non-standard ethylene/a-olefin gas phase copolymerization reaction mechanism, utilizing MWD and short chain branch distribution (SCBD) as objective functions.…”

Section: Introductionmentioning

confidence: 99%

Kinetic Parameter Estimation of the Polyethylene Process by Bayesian Optimization

Fan,

Zhang,

Hong

et al. 2024

Ind. Eng. Chem. Res.

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The design and optimization of polymerization processes rely on accurate kinetic parameters of polymerization reactions since they have a significant impact on polymer properties. We develop a kinetic parameter estimation methodology for non-steady-state olefin polymerization processes. A dynamic model for olefin polymerization reaction kinetics based on the method of moments and instantaneous distribution method is established, which considers reaction temperature fluctuations and concentration variation during polymerization. Bayesian optimization (BO) algorithm is applied in the parameter estimation framework, where the kinetic model is treated as a black box function. The effectiveness of the method developed in this article was demonstrated through three cases, and the parameter estimation strategies used in other literature studies were compared. Additionally, we conduct a comparison of the fitting and extrapolation results obtained from diverse algorithms. Notably, BO emerges as a favorable alternative to deterministic algorithms, as it circumvents the challenges inherent in utilizing gradient-based optimization methods for complex polymerization dynamics models and is more suitable for scenarios with fast prediction in highthroughput experiments. Furthermore, using a dynamic kinetic model is crucial for kinetic parameter estimation in non-steady-state olefin polymerization, as it can reflect the dynamic changes with reaction temperature and concentrations.

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“…The molecular weight distribution (MWD) and chemical composition distribution (CCD) of ethylene/1-olefin copolymers determine their properties . The MWD is typically quantified by gel permeation chromatography, − while the CCD can be measured by temperature rising elution fractionation, − crystallization elution fractionation, crystallization analysis fractionation, − and high-temperature thermal gradient interaction chromatography. − However, these analytical techniques can only measure the distribution of the 1-olefin fraction in statistical copolymers. They are inadequate to characterize the features of the OBC microstructure such as the distribution of number of blocks in the copolymer population, the distributions of lengths of hard and soft blocks, and the distribution of chains with specific chemical compositions.…”

Section: Introductionmentioning

confidence: 99%

Using Probability Models to Design the Microstructure of Linear Olefin Block Copolymers

Chayrattanaroj,

Anantawaraskul,

Soares

2024

Macromolecules

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Olefin block copolymers (OBCs)�a new type of linear thermoplastic ethylene/1-olefin elastomer�are made via chainshuttling polymerization using two catalysts with different reactivity ratios and a chain-shuttling agent. The microstructure of the OBCs has been analyzed using standard characterization techniques, but these methods cannot reveal the details of their molecular architectures, such as the distribution of the number of blocks in the polymer population; these finer microstructural features fall in the realm of mathematical models. In this article, we developed probability model equations to describe the microstructure of the OBCs and validated our solutions with Monte Carlo simulations. These new equations describe the distributions of molecular weight, chemical composition, number and length of blocks in OBCs made in a continuous stirred-tank reactor operated at steady-state conditions. We also developed a new method to predict the multimodality of the chemical composition distribution of OBCs (which can be experimentally measured) to assist in the design of new OBC materials.

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A Methodology for Estimating Kinetic Parameters and Reactivity Ratios of Multi‐site Type Catalysts Using Polymerization, Fractionation, and Spectroscopic Techniques

Cited by 32 publications

References 31 publications

Heterogeneity of Active Sites in the Polymer Chain Transfer Reactions at Olefin Polymerization over Multisite Supported Ziegler-Natta Catalysts

Heterogeneity of Active Sites in the Polymer Chain Transfer Reactions at Olefin Polymerization over Multisite Supported Ziegler-Natta Catalysts

Kinetic Parameter Estimation of the Polyethylene Process by Bayesian Optimization

Using Probability Models to Design the Microstructure of Linear Olefin Block Copolymers

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