Dielectric properties of hydrazine and its aqueous solutions

Verstakov, E. S.; Kessler, Yu. M.; Тарасов, А. П.; Khar'kin, V. S.; Yastremskii, P. S.

doi:10.1007/bf00746961

Cited by 2 publications

(8 citation statements)

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“…7. The relaxation times from microwave measurements of solution of hydrazine mentioned in a previous section [48,49] overlap the bulk water data, as well as the relaxation times deduced from diffusion of bulk water data [83,95]. The lines are VFTH fits to the data of the hydrazine solutions published by Minoguchi et al [20,21].…”

Section: Dynamics Of Water At High Temperatures and The Purported "Fr...mentioning

confidence: 54%

“…( 6). [92,93,79,94] and the relaxation times deduced from diffusion data (cyan solid triangles) [83,95]; just above (green crossed diamonds) the relaxation times from microwave measurements of solution of hydrazine [48,49]. The violet and green lines are VFTH fits to the data of the hydrazine solutions published by Minoguchi et al [20,21].…”

Section: Discussionmentioning

confidence: 98%

“…The temperature dependence of   from dielectric study of Minoguchi et al and from microwave measurements [48,49] was fitted by the Vogel-Fulcher-Tammann-Hesse equation. The T g obtained as the temperature at which   =100 s for the solutions with 20, 26.5, and 33 mol % N 2 H 4 are almost identical with values of 136.3, 135.6, and 137.6 K respectively, and not far from T g =125 5 K of neat N 2 H 4 .…”

Section: Aqueous Solutions Of H 2 O-h 2 O 2 and H 2 O-n 2 Hmentioning

confidence: 99%

“…Logarithm of relaxation time versus reciprocal temperature for different systems. At the left bottom dielectric relaxation times  D for bulk water (dark green open square, green open circles and open triangles) from[92,93,79,94] and the relaxation times deduced from diffusion data (cyan solid triangles)[83,95]; just above (green crossed diamonds) the relaxation times from microwave measurements of solution of hydrazine[48,49]. The violet and green lines are VFTH fits to the data of the hydrazine solutions published by Minoguchi et al[20,21].…”

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confidence: 97%

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Resolving the controversy on the glass transition temperature of water?

Capaccioli

Ngai

2011

The Journal of Chemical Physics

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We consider experimental data on the dynamics of water (1) in glass-forming aqueous mixtures with glass transition temperature T(g) approaching the putative T(g) = 136 K of water from above and below, (2) in confined spaces of nanometer in size, and (3) in the bulk at temperatures above the homogeneous nucleation temperature. Altogether, the considered relaxation times from the data range nearly over 15 decades from 10(-12) to 10(3) s. Assisted by the various features in the isothermal spectra and theoretical interpretation, these considerations enable us to conclude that relaxation of un-crystallized water is highly non-cooperative. The exponent β(K) of its Kohlrausch stretched exponential correlation function is not far from having the value of one, and hence the deviation from exponential time decay is slight. Albeit the temperature dependence of its α-relaxation time being non-Arrhenius, the corresponding T(g)-scaled temperature dependence has small steepness index m, likely less than 44 at T(g), and hence water is not "'fragile" as a glassformer. The separation in time scale of the α- and the β-relaxations is small at T(g), becomes smaller at higher temperatures, and they merge together shortly above T(g). From all these properties and by inference, water is highly non-cooperative as a glass-former, it has short cooperative length-scale, and possibly smaller configurational entropy and change of heat capacity at T(g) compared with other organic glass-formers. This conclusion is perhaps unsurprising because water is the smallest molecule. Our deductions from the data rule out that the T(g) of water is higher than 160 K, and suggest that it is close to the traditional value of 136 K.

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Section: Dynamics Of Water At High Temperatures and The Purported "Fr...mentioning

confidence: 54%

Section: Discussionmentioning

confidence: 98%

Section: Aqueous Solutions Of H 2 O-h 2 O 2 and H 2 O-n 2 Hmentioning

confidence: 99%

mentioning

confidence: 97%

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Resolving the controversy on the glass transition temperature of water?

Capaccioli

Ngai

2011

The Journal of Chemical Physics

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“…The dielectric relaxation time of a molecular liquid can now be determined over a range of 20 orders of magnitude, from times as long as one year 19 to values as short as 10 -14 s , extensions to low temperatures near T g have, to the best of our knowledge, never been performed. Thus an investigation of the dielectric relaxation behavior of these water-like systems near their glass transition temperatures, particularly in relation to water content in water-rich solutions, should provide important information relevant to the understanding of water itself in the region of controversy.…”

Section: Introductionmentioning

confidence: 99%

Dielectric Relaxation in Aqueous Solutions of Hydrazine and Hydrogen Peroxide: Water Structure Implications

2004

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We report dielectric relaxation studies of aqueous solutions of two water-like molecules, hydrazine and hydrogen peroxide, in the neighborhood of their glass transition temperatures, T g . These solutions behave in a rather simple manner, reminiscent of the diols and diamines of which they are the limiting cases. Their relaxations near T g are more nearly exponential than in most other cases, and they show essentially no secondary relaxations. Supercooled hydrazine solutions are the more stable. At the composition 20 mol % N 2 H 4 , the liquid exhibits precise time-temperature-superposition (TTS) behavior. At higher N 2 H 4 contents, a weak deviation from TTS appears. The temperature dependence of the relaxation time follows the Vogel-Fulcher-Tammann (VFT) equation, and the strength parameter, D, is similar to that of glycerol, a liquid of intermediate fragility.The VFT divergence temperature, T 0 , lies close to the Kauzmann temperature, T K , determined earlier from calorimetric studies implying that the thermodynamic and kinetic measures of fragility are very similar. T g values assessed from T(τ)100s) agree well with observed calorimetric, T g 's. Extrapolation of the relaxation time behavior to pure water would imply a T g for water of 135-140 K; however, the dielectric behavior of amorphous solid water in the temperature range 130-160 K is completely different from that of the solutions showing no sign of the loss peak exhibited by all the solutions. Based on the solution behavior, water controversially must either remain glassy up until the temperature of crystallization or be an almost ideally strong liquid above 136 K. Having shown elsewhere how this implies glassy character up to LDA crystallization and a T g above 160 K, we now examine the implications for water structure reorganization on dissolution of solutes, certain glycols excepted. It appears that the water in these solutions behaves like ice III rather than ice I. † Part of the special issue "Frank H. Stillinger Festschrift".

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Dielectric properties of hydrazine and its aqueous solutions

Cited by 2 publications

References 5 publications

Resolving the controversy on the glass transition temperature of water?

Resolving the controversy on the glass transition temperature of water?

Dielectric Relaxation in Aqueous Solutions of Hydrazine and Hydrogen Peroxide: Water Structure Implications

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