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Ho, Patience C.; Bianchi, Hugo L.; Palmer, Donald A.; Wood, Robert H.

doi:10.1023/a:1005146332605

Cited by 94 publications

(61 citation statements)

References 12 publications

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“…The new probe is developed in cooperation with an instrument company ͑JEOL͒ and built into a 500 MHz system ͑JEOL ECA500͒ with a wide-bore superconductor magnet ͑11.3 T͒. The new high-temperature probe is multinuclear and can cover a wide range of resonance frequencies of 36-500 MHz; 14 N, 35 Cl, 133 Cs, 17 O, 2 H, 29 Si, 13 C, 23 Na, 31 P, 19 F, and 1 H can be measured with a single probe.…”

Section: A Apparatusmentioning

confidence: 99%

“…However, the method to observe translational dynamics in supercritical water has been limited to the electric conductivity measurement. [17][18][19][20][21][22] The recent progress in supercritical water reactions increases the necessity of our understanding of the translational dynamics of neutral molecules, such as water and organic molecules, that cannot be observed by electric conductivity. A widely applicable apparatus for the diffusion measurement in supercritical water is desired to be developed.…”

Section: Introductionmentioning

confidence: 99%

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A new high-temperature multinuclear-magnetic-resonance probe and the self-diffusion of light and heavy water in sub- and supercritical conditions

Yoshida

Wakai

Matubayasi

et al. 2005

The Journal of Chemical Physics

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A high-resolution nuclear-magnetic-resonance probe (500 MHz for 1H) has been developed for multinuclear pulsed-field-gradient spin-echo diffusion measurements at high temperatures up to 400 degrees C. The convection effect on the self-diffusion measurement is minimized by achieving the homogeneous temperature distributions of +/-1 and +/-2 degrees C, respectively, at 250 and 400 degrees C. The high temperature homogeneity is attained by using the solid-state heating system composed of a ceramic (AlN) with high thermal conductivity comparable with that of metal aluminium. The self-diffusion coefficients D for light (1H2O) and heavy (2H2O) water are distinguishably measured at subcritical temperatures of 30-350 degrees C with intervals of 10-25 degrees C on the liquid-vapor coexisting curve and at a supercritical temperature of 400 degrees C as a function of water density between 0.071 and 0.251 gcm3. The D value obtained for 1H2O is 10%-20% smaller than those previously reported because of the absence of the convection effect. At 400 degrees C, the D value for 1H2O is increased by a factor of 3.7 as the water density is reduced from 0.251 to 0.071 gcm3. The isotope ratio D(1H2O)D(2H2O) decreases from 1.23 to approximately 1.0 as the temperature increases from 30 to 400 degrees C. The linear hydrodynamic relationship between the self-diffusion coefficient divided by the temperature and the inverse viscosity does not hold. The effective hydrodynamic radius of water is not constant but increases with the temperature elevation in subcritical water.

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Section: A Apparatusmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A new high-temperature multinuclear-magnetic-resonance probe and the self-diffusion of light and heavy water in sub- and supercritical conditions

Yoshida

Wakai

Matubayasi

et al. 2005

The Journal of Chemical Physics

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“…A comparison to benzene will provide a better understanding of dynamical issues in supercritical fluids that have generated considerable interest during the past decades. [32][33][34][35][36][37][38][39][40][41][42][43] Although the structure and dynamics in benzene are slightly anisotropic at room temperature, 44,45 the anisotropy is much weaker than in water, especially at high temperatures. 45 The studies on static structures have shown that the preference for parallel and perpendicular configurations in benzene almost disappears in supercritical conditions, 45 whereas the orientational preference in hydrogen bonding clearly exists in supercritical water.…”

Section: Introductionmentioning

confidence: 99%

Solvation shell dynamics studied by molecular dynamics simulation in relation to the translational and rotational dynamics of supercritical water and benzene

Yoshida

Matubayasi

Nakahara

2007

The Journal of Chemical Physics

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The solvation shell dynamics of supercritical water is analyzed by molecular dynamics simulation with emphasis on its relationship to the translational and rotational dynamics. The relaxation times of the solvation number (tau S), the velocity autocorrelation function (tau D), the angular momentum correlation function (tau J), and the second-order reorientational correlation function (tau 2R) are studied at a supercritical temperature of 400 degrees C over a wide density region of 0.01-1.5 g cm(-3). The relaxation times are decomposed into those conditioned by the solvation number n, and the effect of the short-ranged structure is examined in terms of its probability Pn of occurrence. In the low to medium-density range of 0.01-0.4 g cm(-3), the time scales of water dynamics are in the following sequence: tau D>tau S approximately or > tau J approximately or > tau 2R. This means that the rotation in supercritical water is of the "in-shell" type while the translational diffusion is not. The comparison to supercritical benzene is also performed and the effect of hydrogen bonding is examined. The water diffusion is not of the in-shell type up to the ambient density of 1.0 g cm(-3), which corresponds to the absence of the transition from the collision to the Brownian picture, whereas such transition is present in the case of benzene. The absence of the transition in water comes from the fast reorganization of the hydrogen bonds and the enhanced mobility of the solvation shell in supercritical conditions.

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“…Recently, the Oak Ridge's static conductivity cell was modifi ed (Ho et al, 2000a;2000b; and converted into a fl ow-trough cell able to operate with high accuracy at densities lower than 0.4 g·cm −3 . So far, the maximum temperature achieved was 410 °C and the maximum pressure was 33 MPa, but it is expected that the cell could operate up to 600 °C and 300 MPa.…”

Section: Flow-through Conductivity Cellmentioning

confidence: 99%

“…(4.19) requires very precise conductivity data, as those measured in hydrothermal systems with the fl ow-through cells (Zimmerman et al, 1995;Gruszkiewicz and Wood, 1997;Ho et al, 2000a;2000b;. Wood and co-workers (Sharygin et al, 2001) have compared the FHFP and TBBK equations for associated electrolytes using conductivity data for aqueous NaCl at high temperature and pressure (623.9 K, 19.79 MPa and r = 0.596 g·cm −3 ).…”

Section: Associated Electrolytesmentioning

confidence: 99%

Electrical Conductivity in Hydrothermal Binary and Ternary Systems

Corti

2008

Hydrothermal Experimental Data

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Cited by 94 publications

References 12 publications

A new high-temperature multinuclear-magnetic-resonance probe and the self-diffusion of light and heavy water in sub- and supercritical conditions

A new high-temperature multinuclear-magnetic-resonance probe and the self-diffusion of light and heavy water in sub- and supercritical conditions

Solvation shell dynamics studied by molecular dynamics simulation in relation to the translational and rotational dynamics of supercritical water and benzene

Electrical Conductivity in Hydrothermal Binary and Ternary Systems

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