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Author: search.filters.author.Ise, NorioSubject: search.filters.subject.Kinetics

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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).
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    Kinetics of Anionic Polymerizations of Styrene and Its m- and p-Derivatives: Hammett’s Relations
    (Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1972, 68 (1), 1972) Hirohara, Hideo; Nakayama, Masatoshi; Ise, Norio
    The kinetics of anionic polymerizations of styrene, m-methylstyrene, p-isopropylstyrene, and p-methylstyrene were investigated in tetrahydrofuran (THF) at 25°C with Cs+ as gegenion in the presence and absence of an electric field. Anionic polymerizations of m- and p-methylstyrenes in 2-methyltetrahydrofuran (MTHF) with Na+ as gegenion were also studied. The ion-pair rate constants k′p, the free ion rate constants k″p and the dissociation constants K of the styrene derivatives were generally smaller in both solvents than those of styrene. Conductance studies showed that the K values of the caesium salts are practically the same in THF. It was found that the free anions of these living polymers in MTHF are half as reactive as in THF. The field acceleration effect was hardly perceptible in THF. Following earlier studies of the field effect, the solvation ability of ethereal solvents to free carbanions was concluded to decrease along the series dimethoxyethane (DME) > THP ≃ MTHF > THF. A value of (12 ± 2)× 104 M–1 s–1 was attributed to the “desolvated” free ion rate constant for living polystyrene. Hammett's relations of the two systems Cs+/THF and Na+/MTHF were examined for kp, k′p, k″p, and K, independently. The reactivity constants ρ for kp and K were dependent on systems whereas those for k″p were not.