Dynamic simulation and experimental evaluation of EPDM terpolymerization with vanadium-based catalyst

Haag, M.; Santos, João Henrique Zimnoch dos; Dupont, Jaı̈rton; Secchi, Argimiro Resende

doi:10.1002/(sici)1097-4628(19981107)70:6<1173::aid-app15>3.0.co;2-0

Cited by 11 publications

(23 citation statements)

References 16 publications

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“…Interestingly, the materials formed at lowest ENB concentrations, EPDM-1 and EPDM-2, were unimodal, high molecular weight polymers with M -w higher than was observed for the EP copolymer prepared under the same conditions; indeed, M -w was higher in EPDM-2 (8.2 6 10 5 ) than in EPDM-1 (7.7 6 10 5 ). In contrast, the material from experiment EPDM-3 was predominantly a unimodal polymer (M The apparent increase in M -w as the incorporation of ENB increases is noteworthy, as the opposite effect is observed with vanadium-based catalysts, [8] while both increases [2 b,c] and decreases [2 a, c, e, g] are reported for various metallocene systems. Presumably, chain transfer via b-elimination is less facile after incorporation of an ENB molecule in the titanium catalyst system.…”

Section: Resultsmentioning

confidence: 99%

EPDM Synthesis by the Ziegler Catalyst Cp*TiMe3/B(C6F5)3

Bavarian

Baird²,

Parent

2001

Macromol. Chem. Phys.

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The utilization of the Ziegler catalyst Cp*TiMe3/B(C6F5)3 for the terpolymerization of ethylene, propylene and 5‐ethylidene‐2‐norbornene to give EPDM is investigated, and the major factors affecting yields, molecular weights, molecular weight distributions and compositional distributions of the EPDM polymers are assessed. High molecular weight polymers with narrow molecular weight distributions are obtained at ˜18°C.

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Section: Resultsmentioning

confidence: 99%

EPDM Synthesis by the Ziegler Catalyst Cp*TiMe3/B(C6F5)3

Bavarian

Baird²,

Parent

2001

Macromol. Chem. Phys.

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“…The intrinsic complexity of olefin copolymerization with Ziegler–Natta catalysts demands reaction models to control and better understand the polymerization process. The Ziegler–Natta process is one of the most studied polymerization systems for modeling,1–17 and several reviews on olefin polymerization with Ziegler–Natta catalysts are available in the literature 18–26…”

Section: Introductionmentioning

confidence: 99%

“…Haag et al6 proposed a dynamic model based on the method of single moments with some simplifications to describe influence of Al/V ratio and diene concentration on the reaction yield and polymer characteristics such as molecular weight, polydispersity index (PDI), and ethylene incorporation.…”

Section: Introductionmentioning

confidence: 99%

Dynamic modeling and experimental evaluation of olefin copolymerization with vanadium‐based catalysts

Pourhossaini

Vasheghani‐Farahani

Gholami³

et al. 2006

J of Applied Polymer Sci

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ABSTRACT:In this study, we developed a mathematical model for olefin copolymerization using soluble ZieglerNatta catalysts in a semibatch reactor to predict the reaction rate and polymer characteristics (i.e., molecular weight, polydispersity, and ethylene content) as functions of the reaction parameters (i.e., time, temperature, pressure, concentrations, and so on) accurately. The proposed model differs from others because it considers the olefin copolymerization as a dynamic process and applies double moments for two reactants (ethylene and propylene) in the presence of hydrogen. To establish the model validity, the copolymerization was performed with VOCl 3 -Al 2 Et 3 Cl 3 systems with hydrogen as a molecular weight controlling agent. The dynamic model was able to reproduce the experimental data within experimental accuracy and accurately demonstrated the fundamental importance of the polymerization variables on the final properties of the polymer material in the copolymerization of ethylene and propylene with Al/V ratios of up to 28 before synthesis.

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“…It is widely accepted that the catalytic species in vanadium polymerization is in the trivalent oxidation state V(III) and that the role of organohalide promoters is to oxidize the vanadium species, reduced by the alkylaluminum cocatalyst to divalent V(II), back to the trivalent state [1][2][3] .Mechanisms for polymerizations with vanadium have been proposed and kinetic modelling has been attempted in the past [4][5][6][7][8][9] , but monomer-coordinated species and two-site behaviour, occasionally alluded to but not characterized, were not considered. In the present study, EPM and EPDM polymers were made in solution with a vanadium catalyst in a continuous stirred-tank reactor.…”

mentioning

confidence: 99%

“…Mechanisms for polymerizations with vanadium have been proposed and kinetic modelling has been attempted in the past [4][5][6][7][8][9] , but monomer-coordinated species and two-site behaviour, occasionally alluded to but not characterized, were not considered. In the present study, EPM and EPDM polymers were made in solution with a vanadium catalyst in a continuous stirred-tank reactor.…”

mentioning

confidence: 99%

Steady‐State Model for Olefin Polymerization With a Two‐Site Vanadium Catalyst in a Continuous Stirred‐Tank Reactor

D’Agnillo

Soares

Doremaele

2005

Macro Materials & Eng

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Copolymers based on ethylene, propylene, and dienes (EPDM) are often commercially produced with a vanadium catalyst, an alkylaluminum cocatalyst and optionally a halocarbon promoter. It is widely accepted that the catalytic species in vanadium polymerization is in the trivalent oxidation state V(III) and that the role of organohalide promoters is to oxidize the vanadium species, reduced by the alkylaluminum cocatalyst to divalent V(II), back to the trivalent state [1][2][3] .Mechanisms for polymerizations with vanadium have been proposed and kinetic modelling has been attempted in the past [4][5][6][7][8][9] , but monomer-coordinated species and two-site behaviour, occasionally alluded to but not characterized, were not considered. In the present study, EPM and EPDM polymers were made in solution with a vanadium catalyst in a continuous stirred-tank reactor.Observations about this system include [10] :• the catalyst system without promoter and without hydrogen produces polymer with bimodal MWDs, suggesting two-site catalyst behaviour.• the addition of catalyst promoter causes an order of magnitude increase in catalyst productivity, and eliminates the higher-MW component in the MWD.• the addition of hydrogen also precludes bimodal MWDs, regardless of the presence of promoter.• except at very low monomer concentrations, the polymerization rate has a zero-order rather than a first-order response to increasing monomer concentration.These seldom-discussed features of vanadium catalysis are illustrated by a selection of EP copolymerizations, and can be explained with the aid of a polymerization model. The polymerization rate, which is almost zero-order with respect to monomer at higher monomer concentrations (with or without halocarbon promoter) is described by a mechanism whereby propylene forms a stable propylene-active site complex prior to insertion in the growing polymer chain. Model results suggest that the second active site type, which makes high molecular weight polymer, is formed from the monomer-coordinated species. Although polymerisation rate and MWD can be described by the kinetic model, many fundamental questions require discussion and further investigations.

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Dynamic simulation and experimental evaluation of EPDM terpolymerization with vanadium-based catalyst

Cited by 11 publications

References 16 publications

EPDM Synthesis by the Ziegler Catalyst Cp*TiMe3/B(C6F5)3

EPDM Synthesis by the Ziegler Catalyst Cp*TiMe3/B(C6F5)3

Dynamic modeling and experimental evaluation of olefin copolymerization with vanadium‐based catalysts

Steady‐State Model for Olefin Polymerization With a Two‐Site Vanadium Catalyst in a Continuous Stirred‐Tank Reactor

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