Telechele des methylpropens durch kationische polymerisation

Freyer, Christian V.; Mühlbauer, Hans-Peter; Nuyken, Oskar

doi:10.1002/apmc.1986.051450104

Cited by 15 publications

(3 citation statements)

References 10 publications

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“…The cumyl cation is of particular importance in macromolecular chemistry. On the one side, it is the active electrophile in Kennedy’s INIFER process, , and on the other side, it is closely related to the propagating species in the carbocationic polymerization of α-methylstyrene.…”

Section: Introductionmentioning

confidence: 99%

Electrophilic Reactivity of the α,α-Dimethylbenzyl (Cumyl) Cation

Ammer

Mayr

2010

Macromolecules

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The cumyl cation was generated by laser flash photolysis of cumyl tris(4-chlorophenyl)phosphonium tetrafluoroborate in CH2Cl2 and identified by its UV spectrum. From the decay of its absorbance at λ = 335 nm in the presence of variable concentrations of several nucleophiles with CC double bonds, rate constants for the reactions of the cumyl cation with these π-nucleophiles were determined. The linear free energy relationship log k 20°C = s(N + E) (eq ) was used to calculate the electrophilicity parameter E = 5.74 of the cumyl cation from the rate constants determined in this work and the previously reported N and s parameters of the nucleophilic reaction partners. Substitution of E of the cumyl cation and of the previously reported N and s parameters of α-methylstyrene into eq predicts the temperature-independent rate constant of the addition of the cumyl cation to α-methylstyrene (1.2 × 108 M−1 s−1), which is relevant for the cationic polymerization of α-methylstyrene.

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Section: Introductionmentioning

confidence: 99%

Electrophilic Reactivity of the α,α-Dimethylbenzyl (Cumyl) Cation

Ammer

Mayr

2010

Macromolecules

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“…The knowledge of the rate constants of the individual steps of a polymerization reaction is the key to an efficient control of such processes . Numerous attempts to determine the propagation rate constants of the cationic polymerization of isobutylene yielded values from 6 × 10 3 to 1.5 × 10 8 L mol -1 s -1 . − While Marek reported a value of 6 × 10 3 L mol -1 s -1 for the AlCl 3 /TiCl 4 -initiated polymerization in heptane 2 and a value of 7.9 × 10 5 L mol -1 s -1 for the light-induced bulk polymerization with VCl 4 , Giusti determined a rate constant of 1.2 × 10 4 L mol -1 s -1 for the polymerization in methyl chloride with Et 2 AlCl/Cl 2 as initiating system . Plesch calculated a propagation rate constant of 9.1 × 10 3 L mol -1 s -1 from Ueno's polymerizations of isobutylene in methylene chloride with ionizing radiation as a source for carbocations, , whereas the bulk polymerization of Taylor yielded a value of 1.5 × 10 8 L mol -1 s -1 .…”

Section: Introductionmentioning

confidence: 99%

A Novel Method for the Determination of Propagation Rate Constants: Carbocationic Oligomerization of Isobutylene

Roth

Mayr

1996

Macromolecules

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The tertiary carbenium ions 2 + and 3 +, models of the propagating species in carbocationic isobutylene polymerization, are generated from the tertiary chlorides 2c and 3c with a Lewis acid in the presence of isobutylene (1c) and one of the allylsilanes 1a or 1b, which act as terminators. Since the rate of the termination reaction is known, the ratio of the telomerization products can be evaluated to give a propagation rate constant of (6 ± 2) × 108 L mol-1 s-1 (independent of temperature) for the carbocationic oligomerization of isobutylene in dichloromethane.

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“…System C [48][49][50][51] : 2-Chloro-2,4,4-trimethylpentane with TiCl 4 in a solvent mixture of dichloromethane and hexane.…”

Section: Polymerization Of Isobutenesmentioning

confidence: 99%