Evaluation of the hydrocarbon condensation polymerisation reaction by means of model compounds. II. The reaction of with n‐alkyl chlorides and iodides, and sec‐ and tert‐alkyl bromides

Davis, A.; Richards, D. H.; Scilly, N. F.

doi:10.1002/macp.1972.021520114

Cited by 18 publications

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“…Downloaded by UNIV OF MICHIGAN ANN ARBOR on February 18, 2015 | http://pubs.acs.org the products is drastically changed(15). For example, when an equimolar mixture of ethylbromide and styrene reacts in tetrahydrofuran with metallic lithium, the alkyl capped dimer, C 2 H5.CH(Ph).CH2.CH2.CH(Ph).C 2 H 5 forms 90% of the products, about 5% appear as C2H5.CH2.CH(Ph).C2H5, the remainder being a mixture of an alkyl capped trimer and butane.…”

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Mechanisms of Electron-Transfer Initiation of Polymerization: A Quantitative Study

Szwarc

1983

ACS Symposium Series

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Initiation of vinyl, vinylidene or diene polymerization is commonly visualized as an addition of some moiety, X, to a monomer, M, resulting in the formation of a reactive end-group capable of sustaining propagation of polymerization. Depending upon whether X is a radical, a cation, or an anion, the ensuing polymerization is propagated through a radical, cationic, or anionic mechanism, as shown schematically below:In each case one end of a growing polymer is inert while the other is active.Still another mechanism of initiation was proposed in the 1950 f s (1)9 namely, initiation by electron-transfer to monomer. In such an initiation, the electron is transferred from a suitable donor, A or A T , to a monomer, M, converting it into a monomeric radical-anionThe resulting monomeric radical-anions either dimerize into dimeric dianions. e.g., or react with monomer, yielding then dimeric radical-anions,

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confidence: 98%

Mechanisms of Electron-Transfer Initiation of Polymerization: A Quantitative Study

Szwarc

1983

ACS Symposium Series

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Telechelic Polymers

Yaǧcı

Nuyken

Graubner

2004

Encyclopedia of Polymer Science and Technology

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In this article common synthetic routes toward telechelics, which are polymers with well‐defined functional end groups, are described. Telechelic polymers are available via radical, cationic, and anionic polymerization including reversible addition–fragmentation chain transfer polymerization, atom transfer radical polymerization, and nitroxide mediated polymerization. Furthermore, metathesis has become a valuable tool for the preparation of telechelics. Last but not least selected examples are presented in which step‐growth polymerization has been successfully applied for the synthesis of such well‐defined macromolecules. In specific cases chain scission can also be a useful route.

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Evaluation of the hydrocarbon condensation polymerisation reaction by means of model compounds. I. The reaction with n‐alkyl‐bromides

1972

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The title polymerisation involves the reaction in tetrahydrofuran of a-methylstyrene (M) with lithium in the presence of an alkyl dihalide (RX2) to form copolymers. This paper describes a method of studying the effect of changing the experimental parameters on the structure of these copolymers by replacing the dihalide with the corresponding monohalide (HRX). The study is confined to n-alkyl bromides and the relative amounts of the molecules HR-RH and HRM,RH (where n = 1, 2, and 3) have been determined by g.1.c. By this means it is shown that the reaction is diffusion controlled and the rate proportional to lithium surface area. At 1 : 1 monomer : monobalide stoichiometry (equivalent to 2 : 1 monomer : dihalide in the polymer system) the product is -90 yo HRMzRH indicating that the copolymer under these conditions is highly regular with the repeat unit [M-M-R] predominating. The system is extremely sensitive t o the reactant ratio and small deviations from stoichiometry result in significant reductions in dimer yield. ZUSAMMENFASSUNG:Die Bildung von Copolymeren durch Reaktion von a-Methylstyrol (M) in Tetrahydrofuran mit Lithium in Gegenwart von Dihalogenalkanen (RXz) wird beschrieben. Der Ein-flu0 der experimentellen Parameter auf die Struktur der Copolymeren wird untersucht, wobei das Dihalogenid durch das entsprechende Monohalogenid ersetzt ist. Die Untersuchung beschrankt sich auf n-Alkylbromide. Die relativen Mengen an HR-RH und HRM,RH mit n = 1, 2 und 3 wurden gaschromatographisch bestimmt. Es wurde gezeigt, da13 die Reaktion diffusionskontrolliert ablauft und daU die Geschwindigkeit der Lithiumoberflache proportional ist. Bei einem molaren Ausgangsverhaltnis von Monomerem zu Monohalogenid von 1 : 1 (entsprechend einemverhaltnis von 2 : 1 fur das SystemMonomeres/ Dihalogenid) wurden cu. 90% HRMzRH gefunden. Dies zeigt, daS unter den gegebenen Bedingungen ein sehr einheitliches Copolymeres mit der vorherrschenden Sequenz [M-M-R] entsteht. Das System ist sehr empfindlich gegenuber einer Anderung des Ausgangsverhiiltnisses der Komponenten. Geringe Abweichungen vom molaren Verhaltnis 1 : 1 bewirken eine starke Verringerung der Ausbeute an Dimeren.

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Evaluation of the hydrocarbon condensation polymerisation reaction by means of model compounds. II. The reaction of with n‐alkyl chlorides and iodides, and sec‐ and tert‐alkyl bromides

Cited by 18 publications

References 3 publications

Mechanisms of Electron-Transfer Initiation of Polymerization: A Quantitative Study

Mechanisms of Electron-Transfer Initiation of Polymerization: A Quantitative Study

Telechelic Polymers

Evaluation of the hydrocarbon condensation polymerisation reaction by means of model compounds. I. The reaction with n‐alkyl‐bromides

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