A Kinetic Investigation of the Initialization of Catalyzed Chain Growth of Styrene: The Reaction of Cp*<sub>2</sub>ZrCl<sub>2</sub> with Dibenzylmagnesium

Primpke, Sebastian; Deinert, Adrian; Ehlers, Florian; Vana, Philipp

doi:10.1002/macp.201300710

Cited by 3 publications

(20 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Under polymerization conditions, the same species are initially formed as in the absence of monomer, as reported in ref . Consequently, all reactions of Scheme also occur in the polymerization system.…”

Section: Resultsmentioning

confidence: 99%

“…Having the kinetic simulation model at hand, simulations of CCG polymerizations could be performed and used for modeling experimental species concentration traces in order to derive kinetic coefficients. NMR‐data evaluation shown in our previous study ref., which gives access to k alkyl1 and k alkyl2 , via assuming pseudo‐first‐order kinetics for the alkylation reaction, and to the equilibrium constants K 1 = k ex0 / k act0 and K 2 = k ex1 / k act1 , via evaluating species concentration ratios, was also applied in the present study. The respective results are given in Table and compared to the already reported values for the monomer free model system .…”

Section: Resultsmentioning

confidence: 99%

“…Time‐resolved NMR experiments were performed on a VARIAN Unity 300. The synthesis of dibenzyl magnesium was reported before …”

Section: Methodsmentioning

confidence: 99%

“…We thus decided recently to investigate a Zr/Mg system, which is also suited for polymerizing styrene, which is much easier to study by online methods. In a recent publication, we reported about the initialization kinetics of Cp* 2 ZrCl 2 ( A ) with dibenzyl magnesium (BzMgBz) as a model system for the initiation of this type of CCG . BzMgBz was chosen as the model CTA, as Bz cannot undergo β‐hydride elimination, which greatly reduces the complexity of the system.…”

Section: Introductionmentioning

confidence: 98%

“…Based on this previous findings, we expanded the system in the present study to a real CCG system by adding monomer (see Scheme ). In order to identify different species concentrations as function of time, we chose fully deuterated styrene (styrene‐ d 8) as monomer, which is basically invisible in online NMR measurements that were used to obtain time‐dependent concentration profiles.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Modeling of Catalyzed Chain Growth (CCG) Polymerization of Styrene-d 8 using Cp*₂ ZrCl₂ and Dibenzylmagnesium

Primpke

Vana

2015

Macromol. Theory Simul.

Self Cite

View full text Add to dashboard Cite

A kinetic scheme describing Catalytic Chain Growth (CCG) polymerization was developed and implemented into the computer program PREDICI, by which experimental concentration versus time traces of the participating individual species obtained from online NMR spectroscopy as well as full molecular weight distributions could successfully be modeled. The obtained kinetic coefficients are of high statistical significance. The method was demonstrated on the CCG of styrene‐d8 in toluene‐d8 using Cp*2ZrCl2 as the catalyst precursor and dibenzyl magnesium as the transfer agent. The quality of the modeling increased dramatically when assuming a chain‐length dependent propagation. The extraordinarily good quality of the simulation for all participating species proves that the underlying kinetic model is very likely to be correct. The simulations also demonstrate that this CCG system is a controlled process and that increasing the concentration of the catalyst precursor may lead to a reduced overall polymerization rate.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

“…Time‐resolved NMR experiments were performed on a VARIAN Unity 300. The synthesis of dibenzyl magnesium was reported before …”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Modeling of Catalyzed Chain Growth (CCG) Polymerization of Styrene-d 8 using Cp*₂ ZrCl₂ and Dibenzylmagnesium

Primpke

Vana

2015

Macromol. Theory Simul.

Self Cite

View full text Add to dashboard Cite

show abstract

Coordinative Chain Transfer and Chain Shuttling Polymerization

Mundil,

Bravo,

Merle

et al. 2023

Chem. Rev.

View full text Add to dashboard Cite

Coordinative chain transfer polymerization, CCTP, is a degenerative chain transfer polymerization process that has a wide range of applications. It allows a highly controlled synthesis of polyolefins, stereoregular polydienes, and stereoregular polystyrene, including (stereo)block as well as statistical copolymers thereof. It also shows a green character by allowing catalyst economy during the synthesis of such polymers. CCTP notably allows the end functionalization of both the commodity and stereoregular specialty polymers aforementionned, control of the composition of statistical copolymers without adjusting the feed, and quantitative formation of 1-alkenes from ethene. A one-pot one-step synthesis of the original multiblock microstructures and architectures by chain shuttling polymerization (CSP) is also an asset of CCTP. This methodology takes advantage of the simultaneous presence of two catalysts of different selectivity toward comonomers that produce blocks of different composition/microstructure, while still allowing the chain transfer. This affords the production of highly performant functional polymers, such as thermoplastic elastomers and adhesives, among others. This approach has been extended to cyclic esters' and ethers' ring-opening polymerization, providing new types of multiblock microstructure. The present Review provides the state of the art in the field with a focus on the last 10 years.

show abstract

Mechanism and Kinetics of Catalyzed Chain Growth

Primpke¹

Self Cite

View full text Add to dashboard Cite

In this work, the activation and polymerization mechanism of Catalyzed Chain Growth (CCG) polymerization of ethylene and styrene was studied. On the basis of two metallocene catalysts (Cp* 2 ZrCl 2 and Cp* 2 NdCl 2 Li(OEt 2 ) 2 ) and dibenzyl magnesium (BzMgBz) and n-butyloctyl magnesium (BuMgOct) as co-catalysts the mechanism was determined via a model reaction and afterwards transferred to a typical CCG system. The model system consisting of Cp* 2 ZrCl 2 and BzMgBz cannot perform β-hydride elimination and was first studied via Nuclear Magnetic Resonance (NMR). A mechanistic scheme was proposed and kinetic coefficients were successfully derived via modeling in PREDICI TM . Data analysis was simplified due to direct calculation of the coefficients from NMR data. The analytical toolbox was extended to Ultra-Violet/Visible (UV/Vis) spectroscopic studies. Based on this method the influence of di-n-butyl ether (DBE) on the catalyst/co-catalyst system was studied and a strong lowering of rate coefficients was found. The co-catalyst was switched to BuMgOct, where β-hydride elimination of the alkyl chains was found to be fast at 70 • C and dominating the activation mechanism. This hinders the system to perform ethylene polymerization. The UV/Vis method was applied to the reaction of Cp* 2 NdCl 2 Li(OEt 2 ) 2 with BzMgBz. Equilibrium constants between a monoalkylated complex and the benzyl brigded bimetallic Nd-Mg complex were determined in dependence of temperature. The reaction turned out to be strongly dependent on the presence of other coordinating molecules like DBE. The activation mechanism of Cp* 2 ZrCl 2 and BzMgBz was successfully utilized for modeling the polymerization of styrene-d8 by NMR studies. It was found that the basic steps of the exchange reactions are similar to those of activation. The model was successfully extended to the introduction of polymeric species, and kinetic parameters were derived. The process of monomer addition was found to be chain-length dependent and the influence of the single rate coefficients on the reaction were screened. It was found that a low catalyst precursor concentration can lead to a rate enhancement. Addition of tetrahydrofurane was found to be disadvantageous for the polymerization reaction. BuMgOct as co-catalyst leads to a process where the termination reaction of the alkyl Scheme 2.2: Transfer reaction scheme for magnesium derivatives. Adapted with permission from S. Bogaert et al. [21] Copyright 2000 WILEY-VCH Verlag GmbH, D-69451 WeinheimIn contrast to neodymium and iron-based catalysts, the chosen Cp * 2 ZrCl 2 (A)/ BzMgBz model system is non-paramagnetic. Initialization is a critical phase during polymerization in CCG. If the chains from the CTA are not transferred fast and the first monomer addition is slow the MMD will be broadened or the process goes over into a CCTP like polymerization. Results of this section were already published in literature [269] .

show abstract

A Kinetic Investigation of the Initialization of Catalyzed Chain Growth of Styrene: The Reaction of Cp*₂ZrCl₂ with Dibenzylmagnesium

Cited by 3 publications

References 40 publications

Modeling of Catalyzed Chain Growth (CCG) Polymerization of Styrene-d 8 using Cp*₂ ZrCl₂ and Dibenzylmagnesium

Modeling of Catalyzed Chain Growth (CCG) Polymerization of Styrene-d 8 using Cp*₂ ZrCl₂ and Dibenzylmagnesium

Coordinative Chain Transfer and Chain Shuttling Polymerization

Mechanism and Kinetics of Catalyzed Chain Growth

Contact Info

Product

Resources

About

A Kinetic Investigation of the Initialization of Catalyzed Chain Growth of Styrene: The Reaction of Cp*2ZrCl2 with Dibenzylmagnesium

Cited by 3 publications

References 40 publications

Modeling of Catalyzed Chain Growth (CCG) Polymerization of Styrene-d 8 using Cp*2 ZrCl2 and Dibenzylmagnesium

Modeling of Catalyzed Chain Growth (CCG) Polymerization of Styrene-d 8 using Cp*2 ZrCl2 and Dibenzylmagnesium

Coordinative Chain Transfer and Chain Shuttling Polymerization

Mechanism and Kinetics of Catalyzed Chain Growth

Contact Info

Product

Resources

About

A Kinetic Investigation of the Initialization of Catalyzed Chain Growth of Styrene: The Reaction of Cp*₂ZrCl₂ with Dibenzylmagnesium

Modeling of Catalyzed Chain Growth (CCG) Polymerization of Styrene-d 8 using Cp*₂ ZrCl₂ and Dibenzylmagnesium

Modeling of Catalyzed Chain Growth (CCG) Polymerization of Styrene-d 8 using Cp*₂ ZrCl₂ and Dibenzylmagnesium