Effect of pressure on the diffusion coefficient of silver ions in molten alkali metal nitrates

Cleaver, B.; Herdlicka, C.

doi:10.1039/f19767201861

Cited by 4 publications

(2 citation statements)

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“…Watanabe et al 26,[38][39][40] have investigated transport properties for a variety of ILs with different pairs of cations and anions as a function of temperature, in which the molar conductivity ratio Λ imp /Λ NMR (usually termed the Haven ratio by solid-state physicists but called "ionicity" by Watanabe et al, with Λ imp being the measured conductivity and Λ NMR , that calculated from the ionic self-diffusion coefficients using the unmodified Nernst-Einstein equation) corresponds to the factor (1 -∆) in eq 6. For all the ILs studied, they found (1 -∆) to be much smaller than unity (i.e., ∆ is not negligible) and insensitive to changes in temperature between -10 and 80 o C. Consistent with their results for [BMIM]PF 6 , 26 we obtain ∆ ) 0.36-0.39 at atmospheric pressure between 40 and 80 o C. The mean value of 0.38 ( 0.02 for [BMIM]PF 6 is larger than those for molten alkali halides 30,[32][33][34][35][36] and comparable to those for alkali nitrates 30,41 and tetraalkylammonium salts. 42 At 50 and 70 °C, the value of ∆, 0.37 ( 0.02, is essentially independent of pressure to 50 and 150 MPa, respectively (see Figure 2).…”

Section: Discussionsupporting

confidence: 89%

Effect of Pressure on Transport Properties of the Ionic Liquid 1-Butyl-3-methylimidazolium Hexafluorophosphate

et al. 2007

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The self-diffusion coefficients (D) of the cation and anion in the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM]PF6) have been determined together with the electrical conductivity (kappa) under high pressure. All three quantities strongly decrease with increasing pressure to approximately 20% of their atmospheric pressure values at 200 MPa. D(PF6-) is always less than D([BMIM]+), despite the larger van der Waals volume of the cation. The pressure effect on the transport coefficients is discussed in terms of velocity correlation coefficients (VCCs or fij), the Nernst-Einstein equation (ionic diffusivity-conductivity), and the fractional form of the Stokes-Einstein relation (viscosity-conductivity and viscosity-diffusivity). It was found that the VCCs for the cation-cation, anion-anion, and cation-anion pairs are all negative and strongly pressure-dependent, increasing (becoming less negative) with increasing pressure. However, when the values of the VCCs for a given isotherm are normalized relative to the corresponding atmospheric pressure values, they collapse onto a single curve, as might be expected because the pressure should affect the interionic velocity correlations in the same way for each type of interaction. These isothermal curves can be represented by the form exp(alphap + betap2). The Nernst-Einstein deviation parameter, Delta, which depends on the differences between the like-like ion and unlike ion VCCs (f++ + f-- - 2f+-), is very nearly constant under the conditions examined. The diffusion and molar conductivity (Lambda) data are found to fit fractional forms of the Stokes-Einstein relationship with the viscosity, (LambdaT) proportional, variant (T/eta)t and Di proportional, variant (T/eta)t , with t = (0.92 +/- 0.05), independent of both temperature and pressure within the ranges studied and common to the three independently determined properties.

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Section: Discussionsupporting

confidence: 89%

Effect of Pressure on Transport Properties of the Ionic Liquid 1-Butyl-3-methylimidazolium Hexafluorophosphate

et al. 2007

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“…± 10% 42. RbN03 (cont'd) Equation: ± 6.3% 35 aDependence •of diffusion coefficients of Ag + on pressure has been reported in graphical form at 628, 679, and 708 K [226].…”

Section: Diffusion Coefficients In• Molten Saltsmentioning

confidence: 99%

Molten Salts Data: Diffusion Coefficients in Single and Multi-Component Salt Systems

Janz¹,

Bansal²

1982

Journal of Physical and Chemical Reference Data

124

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The property of diffusion is one of the basic properties of fluid systems. In molten salts, more than 700 studies have been reported to August, 1980, with more than 15 diffusion measurement techniques. A critical examination of these studies with a review of the techniques is presented. The results for more than 140 salt systems are reported in this communication as a series of data tables, with numerical values, value judgements, and literature citations. Silicates, slags, and oxide melts are excluded.

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Der Einfluß von Dichte und Temperatur auf die Eigenschaften reiner geschmolzener Salze

Tödheide¹

1980

Angew. Chem.

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Professor Ernst Ulrich Franck zum 60. Geburtstag gewidmetDie geschmolzenen Salze unterscheiden sich von anderen Fliissigkeiten durch eine hohe Ladungstragerkonzentration, auf die viele ihrer Eigenschaften, unter anderem die hohe Ionenleitfahigkeit, zuriickzufuhren sind. Experimentelle und theoretische Untersuchungen haben in den letzten Jahren Informationen iiber die statische und dynamische Struktur dieses Fliissigkeitstyps urnd deren Zusammenhang mit den makroskopischen Eigenschaften erbracht. Sie ergeben ein konsistentes, wenn auch noch unvollkommenes Bild des Verhaltens der Salze iiber weite Temperatur-und Dichtebereiche, insbesondere des Ubergangs vom Isolator zum Ionenleiter, der silch ausgehend vom Salzdampf mit zunehmender Dichte vollzieht.

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Effect of pressure on the diffusion coefficient of silver ions in molten alkali metal nitrates

Abstract: The interdiffusion coefficient of silver ions ( D A ~+ )in molten NaN03, KN03, RbN03 and CsN03 has been measured at temperatures in the range 623-723 K and at pressures up to 1 kbar (1 bar = I2

Cited by 4 publications

References 0 publications

Effect of Pressure on Transport Properties of the Ionic Liquid 1-Butyl-3-methylimidazolium Hexafluorophosphate

Effect of Pressure on Transport Properties of the Ionic Liquid 1-Butyl-3-methylimidazolium Hexafluorophosphate

Molten Salts Data: Diffusion Coefficients in Single and Multi-Component Salt Systems

Der Einfluß von Dichte und Temperatur auf die Eigenschaften reiner geschmolzener Salze

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