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Author: search.filters.author.Takaya, K.Subject: search.filters.subject.Chemistry

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    Anionic Polymerization of Styrene in Binary Mixtures of 1,2-Dimethoxyethane and Benzene
    (Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1974, 70 (07), 1974) Takaya, K.; Ise, Norio
    The kinetics of living anionic polymerizations of styrene has been studied with lithium as gegenion in solution in binary mixtures of 1,2-dimethoxyethane and benzene at 0, 25 and 35°C. The contri bution of intermolecular triple ions is suggested from kinetic and conductivity data. The dissociation constant of the ion pairs increases as the temperature is lowered, while that of the triple ions decreases. Both the ion-pair and triple-ion dissociation constants increase as the dielectric constant is increased. The rate constants for the ion pairs, free ions and triple ions were determined. The triple ions are suggested to be of a solvent-separated intermolecular type and to be much more reactive than the free ions. No effect of electric field on the kinetics was observed in this system.
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    Kinetics of Anionic Polymerization of Styrene in Binary Mixtures of Dimethoxyethane and Benzene
    (Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1974, 70 (07), 1974) Takaya, K.; Yamauchi, S.; Ise, Norio
    The kinetics of anionic polymerization of polystyryl salts with various gegen ions have been investigated spcctrophotomctrically in 1,2-dimethoxyethanc (DME) + benzenc mixtures at 25QC. The behaviour of two types of polymers, viz. one- and two-ended polymers, was studied for sodium and caesium salts. The two-ended sodium salt is as reactive as the one-ended salt, whereas the two- ended caesium salt is less reactive than the one-ended salt. The conductance of the two-ended sodium salt is smaller than that of the one-ended, whereas the conductance of the two-ended caesium salt is larger than that of the one-ended salt. The ion-pair rate constants k'p in the DME +benzene (50 : 50) mixture are 360, 182 and 90 dm3 mol-1 s-1 for the sodium, potassium and caesium salts. The dissociation constants K are 4.7 x IO-10, 1.3 x 1O~10 and 3.5 x IO-13 mol dm-3 for the sodium, potassium and caesium salts. The free ion rate constant kp is 9-10 x 104 dm3 mol-1 s"' for these salts. The contribution of the intra-molecular triple-ion was observed for the two-ended living polystyrene and the rate constant fcp'(c) of this ionic species is ~1000dm3 mol-1 s-1, practically independent of solvent, and; is smaller than the rate constant of the solvent-separated intcrmolccular triple ion (Ap'~1.2x 10s dm3 mol-1 s-1).