Über die Konstitution der Styrololigomeren aus der thermischen Polymerisation

Kurze, Von J.; Stein, Dieter J.; Šimák, P.; Kaiser, R.

doi:10.1002/apmc.1970.050120103

Cited by 38 publications

(11 citation statements)

References 14 publications

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“…The formation of other products is relatively unaffected. The results are consistent with the mechanism of the thermal initiation of polymerization given by reactions [I]- [3]. Interception of the initial styrene dimer 1 by DPPH, reaction [4], as soon as it is formed would prevent hydrogen transfer to a third molecule of styrene, reaction 121 and thereby eliminate formation of 5.…”

Section: Discussionsupporting

confidence: 88%

“…The generally accepted mechanism for the thermal initiation of the polymerization of styrene is given by reactions [I]- [3] (1). where M; is a growing polymer chain.…”

Section: Introductionmentioning

confidence: 99%

“…June [5][6][7]1972. Abstract p. 46. ization and is consumed during the inhibition period (3). The rate of disappearance of DPPH is -85 times the rate of the thermal initiation of polymer chains at 6O"C ( 3 a ) , is zero order with respect to DPPH in styrene, and is second order with respect to styrene in benzene or toluene ( 3 a , 4).…”

Section: Introductionmentioning

confidence: 99%

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Products of reaction between styrene and some radicals with 2,2-diphenyl-1-picrylhydrazyl

Kopecky¹,

Hall²

1981

Can. J. Chem.

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. Can. J. Chem. 59, 3095 (1981). Addition of 2,2-diphenyl-I-picrylhydrazyl DPPH to styrene at 75'C results in little change in the amounts of cis-and trans-1.2-diphenylcyclobutane and 1.2.3,4-tetrahydro-1-phenylnaphthalene, in a slightly smaller amount of I-phenylnaphthalene, and in a considerable increase in the amount of 1.2-dihydro-1-phenylnaphthalene that are formed. Formation of the styrene trimer 1,2.3,4-tetrahydro-I-phenyl-4-(l-phenylethyl)naphthalene is eliminated completely. Products derived from DPPH are I-(4-nitrophenyl)-1-phenyl-2-picrylhydrazine 9 and 1-[2,6-dinitro-4-(l.2,3,4-tetrahydro-4-phenyl-l-naphthyl)phenyl]-2.2-diphenylhydrazine, 10. DPPH intercepts the thermally formed Diels-Alder dimer of styrene as soon as it is formed to give the 1.2,3,4-tetrahydro-4-phenyl-I-naphthyl radical.Thermolysis of bis(l,2,3,4-tetrahydro-4-phenyl-l-naphthyl)diazene in the presence of DPPH yields 20% of 10, 10% of 1-[2,6-dinitro-4-(1.2,3,4-tetrahydro-4-phenyl-l-naphthyl)phenyl]--(4-nitrophenyl)-2-phenylhydrazine and 9 while thermolysis of 1.2-bis(1-pheny1ethyl)diazene in the presence of DPPH yields 9 and 44% of 1-[2.6-dinitro-4-(l-phenylethyl)phenyl]-2.2-diphenylhydrazine showing that substituted benzyl radicals efficiently displace the 4-nitro group of DPPH. The nitro group is transferred to an unsubstituted phenyl group of DPPH. KARL R. KOPECKY et MICHAEL C. HALL. Can. J . Chem. 59. 3095 (1981). L'addition du diphenyl-2.2 picrylhydrazyle (DPPH) au styrene a 75°C ne change que faiblement les quantites de diphenyl-1,2 cyclobutane cis et trans et de tetrahydro-1.2.3,4phenyl-l naphtalene. mais conduit a une quantite legerement plus faible de phenyl-I naphtalene et a une augmentation considerable de dihydro-1.2 phenyl-1 naphtalene. On llimine completement la formation du trimere du styrene, le tetrahydro-l,2.3,4 phenyl-l (phenyl-l ethyl)-4 naphtalene. Les produits obtenus a partir du DPPH sont la (nitro-4 phenyl)-l phenyl-l picryl-2 hydrazine (9) et la [dinitro-2.6 (tetrahydro-1.2,3,4 phenyl-4 naphtyl-1)-4 phenyll-l diphenyl-2,2 hydrazine (10). I,e DPPH intercepte le dimere du styrene, forme thermiquement selon une reaction de Diels-Alder au fur et B mesure qu'il se forme en donnat le radical tetrahydro-1.2,3,4 phenyl-4 naphtyl-I.La thermolyse du bis(tetrahydr0-l.2,3.4 phenyl-4 naphtyl-I) diaztne en presence du DPPH conduit a 20% du compose 10 et a 10% de [dinitro-2,6 (tetrahydro-l,2.3.4phenyl-4 naphtyl-1)-4 phenyll-l (nitro-4 ph6nyl)-2 phenyl-2 hydrazine et au compose 9 tandis que la thermolyse du bis(pheny1-1 ethyl)-1,2 diazcne en prdsence de DPPH conduit au compose 9 et a 44% de [dinitro-2.6 (phenyl-l ethyl)-4 phenyll-l diphenyl-2,2 hydrazine montrant ainsi que le radical portant un substituant benzyle deplace efficacement le groupe nitro du DPPH. Le groupe nitro est transfere au group phenyl non substitue du DPPH.[Traduit par le journal]

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Section: Discussionsupporting

confidence: 88%

“…The generally accepted mechanism for the thermal initiation of the polymerization of styrene is given by reactions [I]- [3] (1). where M; is a growing polymer chain.…”

Section: Introductionmentioning

confidence: 99%

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Products of reaction between styrene and some radicals with 2,2-diphenyl-1-picrylhydrazyl

Kopecky¹,

Hall²

1981

Can. J. Chem.

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“…Aus dem Vergleich von Kettenubertragung und echter Copolymerisation ist zumindest fur die stark kettenubertragenden Verbindungen ersichtlich, daB aus der gaschromatographisch bestimmten Monomerabnahme rl-Werte nach GI. ( 8 ) nur dann direkt bestimmt werden konnen, wenn keinerlei Nebenreaktionen stattfinden. Mit dieser Unsicherheit bleiben solche r-Werte meist behaftet, auch wenn sich die gaschromatographische Methode sehr bequem zur r-Wert-Bestimmung anbietet 10).…”

Section: Grundlagen Zur Bestimmung Der Obertragungskonstantenunclassified

Kinetik der radikalischen copolymerisation α‐substituierter styrole mit styrol. 3. Teil. Das zusammenwirken von copolymerisation, retardierung und kettenübertragung in abhängigkeit von der chemischen struktur

Fischer

Lüders

1972

Makromol. Chem.

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ZUSAMMENFASSUNG:An einer Serie von zehn teilweise erstmalig syntlietisierten a-substituierten Styrolen wird durch kinetische Messungen bei llO°C gezeigt, da8 solche Verbindungen zusammen mit Styrol nach dem Mechanismus einer Copolymerisation reagieren, jedoch je nach dem Charakter des a-Substituenten verschieden stark retardieren oder zur Ketteniibertragung fuhren.Hierbei zeigen a-Alkylstyrole kaum Ketteniibertragung, jedoch eine urn so gronere Retardierung, je sperriger der a-Substituent ist. a-Arylalkylstyrole vom Typ 4-substituierter 2.4-Diphenylbuten(l)-derivate fiihrcn hingegen zu einer merklichen Kettenubertragung, wie die abertragungskonstanten von 0,29 und 0,26 der Verbindungen 4-Methyl-2.4-diphenylpcnten(l) bzw. 2.4.4-Triphenylpenten(l) beweisen.Die einzelnen Geschwindigkeitskonstanten fur Kettenwachstum und Ketteniibertragung werden berechnet oder grol3enordnungsma0ig abgeschatzt. SUMMARY:The copolymerization of styrene with a series of ten a-substituted styrenes, partially synthesized for the first time, was investigated by kinetic measurements. All compounds react with styrene according to the mechanism of copolymerization. The extent of the observed retardation or chain transfer reaction depends on the chemical nature of the a-substituent.Some a-akylstyrenes scarcely show chain transfer, yet the more bulky the a-substituent is, the more retardation could be observed. On the other hand a-arylalkylstyrenes of the type of 4-substituted 2.4-diphenyl-1-butene-derivates cause an evident chain transfer as can be seen from the chain transfer constants of 0,29 and 0,26 from 4-methyl-2.4-diphenyl-1-pentene and 2.4.4-triphenyl-l-pentene, respectively.The single rate constants of chain propagation and chain transfer are calculated or estimated.

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“…As seen from the Table the relative rate constants Table 1. Relative rate constants of polymer branching reactions In vinyl acetate polymerization; the rate constants of the substitution reactions (36) and (39) were based on k , , and those of the addition reactions (37) and (40) While the occurrence of reaction (43) and its secondary reactions is beyond dispute, Nozakura et al1321 assume that reaction (42) can be neglected in comparison with the competing reaction (43). The reaction sequence (41), (37) was first proposed by ~~h~~~t [ 3 1 .…”

Section: Polymer Branching Reactionsmentioning

confidence: 99%

Kinetics and Mechanism of Radical Polymerization

Mehnert

1974

Angew. Chem. Int. Ed. Engl.

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Low molecular reactions are frequently accompanied by side reactions producing a whole spectrum of by-products whose removal in purification operations generally causes little difficulty because the major and side products usually differ sufficiently in their properties. Hence detailed kinetic studies in low molecular chemistry can claim industrial interest only insofar as they aim to reduce the rate of formation of side products. The situation is completely different in polymer chemistry, where the terms major and side product no longer apply. Instead, one obtains mixtures of similar and/or isomeric molecules which differ so little with regard to molecular weight and structure that resolution into pure substances or isolation of pure substances becomes practically impossible. However, since all partial reactions exert a direct influence on the product spread, i.e. the composition and properties of a product mixture are modified by any change in operating conditions, detailed kinetic analyses embracing all relevant partial reactions are an essential prerequisite for the production of defined polymeric products on any scale. This progress report illustrates the importance of kinetics for radical polymerization with the aid of selected examples.

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Über die Konstitution der Styrololigomeren aus der thermischen Polymerisation

Cited by 38 publications

References 14 publications

Products of reaction between styrene and some radicals with 2,2-diphenyl-1-picrylhydrazyl

Products of reaction between styrene and some radicals with 2,2-diphenyl-1-picrylhydrazyl

Kinetik der radikalischen copolymerisation α‐substituierter styrole mit styrol. 3. Teil. Das zusammenwirken von copolymerisation, retardierung und kettenübertragung in abhängigkeit von der chemischen struktur

Kinetics and Mechanism of Radical Polymerization

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