Browsing by Author "Ise, Norio"

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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.
Catalysis by Polyelectrolytes of the Ag+, Hg2+, and Tl3+ Induced Aquations of Co(NH3)5Br2 +
(Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1973, 69 (1), 1973) Ise, Norio; Matsuda, Yoshinobu
The aquation reaction of Co(NH3)5Br2+ was studied kinetically with Ag’, Hg2 *, and Tl3+ as inducing cations. Addition of polyethylene sulphonate, polystyrene sulphonate and polyphosphate markedly enhanced the reaction. The acceleration factor, ranging from 10 to 104, was dependent on the inducing cations, polyclcctrolytes, their concentrations and the concentrations of foreign salts. The enthalpy of activation (AJ/*) and the entropy of activation (AS*) were decreased by addition of polyclcctrolytes in the case of Agh and Hg2*, as has been observed previously, whereas A//* was not influenced and AS* increased in the case of Tl3*. The behaviour of Tl3+ was ascribed to the strong hydration of this cation.
Heat of Dilution of Aqueous Solutions of Polyacrylates
(Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1973, 69 (1), 1973) Ise, Norio; Mita, Kazuei; Okubo, Tsuneo
The heats of dilution (AH) of aqueous solutions of polyacrylates having various gegenions, i.e., sodium and tetra-alkylammonium (alkyl = methyl, ethyl, n-propyl and n-butyl), were measured. The (A//) value of the sodium polyacrylate was negative in the investigated concentration range (0.005-0.17 mol dm-3), whereas those of organic salts were positive. With the addition of urea, the endothermicity was lessened. These results are discussed in terms of hydrophobic interactions between solute and solvent. The observed (A//) values were found to be in agreement with the values calculated by the theory of Lifson and Katchalsky, when an appropriate value of d In tz/d In 7Ts assumed (a is the ionic radius of rodlikc macroion and T the temperature). However, the assumed value for this parameter was in disagreement with that obtained directly from the partial molal volume measurements (by a factor of ~102).
Kinetics of Anionic Polymerization of o-Methylstyrene in 2-Methyltetrahydrofuran and Tetrahydrofuran
(Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1972, 68 (1), 1972) Hirohara, Hideo; Nakayama, Masatoshi; Kawabata, Ryoichi; Ise, Norio
The kinetics of anionic polymerization of o-methylstyrene were investigated in 2-methyltetrahydrofuran (MTHF) at 25°C with Li+, Na+, K+ and Cs+ as gegenions in the presence and absence of an electric field. Conductance studies showed that the dissociation constants K vary remarkably with the gegenion and that the lithium and sodium salts are dissociated to larger extents than the respective polystyryl salts. The free ion rate constant k″p was ≈ 2 × 104 M–1 s–1, which was smaller than that of polystyrene. From the conductivity data, the field effect was concluded to be due to an increase in k″p with increase of the field strength as in other systems. The k″p reached a limiting value of ≈3 × 104 M–1 s–1 above 3 kV/cm. The ion pair rate constants k′p were 2, 1, 16 and 30 M–1 s–1 for Li+, Na+, K+ and Cs+, respectively. Comparison with polystyrene systems led to the conclusion that the behaviour of poly(o-methylstyryl) salts are due to steric hindrance effects of the methyl group in the ortho position. The field-accelerating effects reflected in the k″p term as in other systems are smaller than that of polystyrene systems. This is discussed in terms of the ortho effect. The kinetics of the caesium salt of poly(o-methylstyrene) were also studied in tetrahydrofuran (THF) at 25°C. The results are compared with those in MTHF.
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).
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.