Experimental and Theoretical Evaluation of the Reactions Leading to Formation of Internal Double Bonds in Suspension PVC

Purmova, Jindra; Pauwels, Kim F. D.; Agostini, M.; Bruinsma, M.; Vorenkamp, Eltio J.; Schouten, A.J.; Coote, Michelle L.

doi:10.1021/ma800583k

Cited by 29 publications

(31 citation statements)

References 33 publications

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“…Intermolecular hydrogen abstractions like chain transfer to monomer and chain transfer to polymer were studied in various systems [106,[137][138][139][140][141]. Intramolecular hydrogen abstractions were investigated as well, focusing on the backbiting reactions that occur when a chain-end radical (CER) abstracts a hydrogen from its own backbone, forming a mid-chain radical (MCR) [70,106,[141][142][143][144].…”

Section: Secondary Reactionsmentioning

confidence: 99%

On the Use of Quantum Chemistry for the Determination of Propagation, Copolymerization, and Secondary Reaction Kinetics in Free Radical Polymerization

2015

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Throughout the last 25 years, computational chemistry based on quantum mechanics has been applied to the investigation of reaction kinetics in free radical polymerization (FRP) with growing interest. Nowadays, quantum chemistry (QC) can be considered a powerful and cost-effective tool for the kinetic characterization of many individual reactions in FRP, especially those that cannot yet be fully analyzed through experiments. The recent focus on copolymers and systems where secondary reactions play a major role has emphasized this feature due to the increased complexity of these kinetic schemes. QC calculations are well-suited to support and guide the experimental investigation of FRP kinetics as well as to deepen the understanding of polymerization mechanisms. This paper is intended to provide an overview of the most relevant QC results obtained so far from the investigation of FRP. A comparison between computational results and experimental data is given, whenever possible, to emphasize the performances of the two approaches in the prediction of kinetic data. This work provides a comprehensive database of reaction rate parameters of FRP to assist in the development of advanced models of polymerization and experimental studies on the topic.

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Section: Secondary Reactionsmentioning

confidence: 99%

On the Use of Quantum Chemistry for the Determination of Propagation, Copolymerization, and Secondary Reaction Kinetics in Free Radical Polymerization

2015

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“…Note that Purmova et al 10 also attribute the formation of terminal double bonds to 1-6 intramolecular hydrogen abstraction reactions, resulting in a double bond between carbons 5 and 6 in the polymer chain. However, the ratio of the ab initio calculated rate coefficients of the 1-5 to the 1-6 intramolecular hydrogen abstraction rate coefficient is close to 1500 at 330 K. Hence, it is justified to conclude that the main route toward terminal double bonds proceeds via 1-5 intramolecular hydrogen abstraction reactions and to neglect the 1-6 intramoleculare hydrogen abstraction reaction in the construction of the reaction network.…”

Section: Kinetic Modelmentioning

confidence: 99%

“…The analogous reaction with a more strained five-membered transition state is not considered, since the resulting branch structure is not detected in PVC. Note that Purmova et al 10 also consider intramolecular 1,2. 1,3.…”

Section: 2-chlorine Shiftmentioning

confidence: 99%

“…9 In agreement with these findings, the pre-exponential factor of these reaction steps is 1 order of magnitude less than the value for the addition reactions involving vinyl chloride. For the β-scission involving a C-Cl bond Arrhenius parameters were chosen in accordance with the value reported by Purmova et al 10 for the β-scission reaction involving a C-Cl bond.…”

Section: Combination Of Reaction and Diffusionmentioning

confidence: 99%

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Microkinetic Modeling of Structural Properties of Poly(vinyl chloride)

2009

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The free radical suspension polymerization of vinyl chloride is modeled at the elementary reaction level, systematically taking into account diffusion limitations. By deriving balances for structurally distinct polymer and radical species the formation of structural defects can be followed: monomer conversion, averages of the molar mass distribution and the structural defects content can be calculated as a function of polymerization time for industrially relevant conditions. A good agreement between literature reported and calculated values for these properties is obtained for a polymerization temperature range of 325-340 K, a dicetyl peroxydicarbonate and dimyristyl peroxydicarbonate initiator concentration range of 0.00069-1.0 wt %, and a monomer conversion range of 12-96%. The increase of the branching content and the decrease of the terminal double bond content at high monomer conversions can be explained in terms of a favoring of monomolecular reactions and the increasing importance of addition reactions to unsaturations at these conditions.

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“…Also for the polymerization of vinyl chloride similar investigations are ongoing. [9,10] In addition to the complex network of elementary reactions the dependency of individual rate coefficients on the reaction environment has to be considered in case the model shall be valid over a wide range of conversion. The gel effect, an observation that is later rendered more precisely as conversion dependency, or even better diffusion controlled kinetics, chain-length-dependencies of termination and propagation play a role in affecting the rate of polymerization.…”

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confidence: 99%

From Fundamental Polymerization Kinetics to Process Application—A Realistic Vision?

Bauer

Becker

Herrmann

et al. 2010

Macro Chemistry & Physics

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This contribution presents a ramble through the past, inspecting the developments of fundamental scientific investigations into the elementary reaction steps of polymerizations. Often the question arises whether benefits from fundamental scientific investigation find their way into industrial practice and how these pay off in better understanding large‐scale processes. The high‐pressure ethene polymerization is the system of interest here because 1) it is a complex process with a world production of several million tons per year and 2) although dealing with system pressures up to 3000 bar is not an easy task, a long history—if not tradition—exists between the scientific efforts to improve the process and the research groups of Franck and Buback in Karlsruhe, Schönemann and Luft in Darmstadt, and later Buback in Göttingen. The scope of this discussion will range from non‐invasive on‐ and in‐line monitoring by spectroscopic methods up to process modeling by advanced kinetic models and their potential for explorative work.magnified image

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Experimental and Theoretical Evaluation of the Reactions Leading to Formation of Internal Double Bonds in Suspension PVC

Abstract: Experimental and theoretical evaluation of the reactions leading to formation of internal double bonds in suspension PVC Purmova, Jindra; Pauwels, Kim F. D.; Agostini, Michela; Bruinsma, Maarten; Vorenkamp, Eltio J.; Schouten, Arend J.; Coote, Michelle L.

Cited by 29 publications

References 33 publications

On the Use of Quantum Chemistry for the Determination of Propagation, Copolymerization, and Secondary Reaction Kinetics in Free Radical Polymerization

On the Use of Quantum Chemistry for the Determination of Propagation, Copolymerization, and Secondary Reaction Kinetics in Free Radical Polymerization

Microkinetic Modeling of Structural Properties of Poly(vinyl chloride)

From Fundamental Polymerization Kinetics to Process Application—A Realistic Vision?

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