Fractional Walden rule for electrolytes in supercooled disaccharide aqueous solutions
The electrical conductivity of CsCl, KCl, Bu4NBr, and Bu 4NI was studied in stable and supercooled (metastable) sucrose and trehalose aqueous solutions over a wide viscosity range. The results indicate that large positive deviations from the Walden rule occur in these systems due to the higher tende...
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2009
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paper:paper_15206106_v113_n16_p5500_Longinotti2023-06-08T16:19:00Z Fractional Walden rule for electrolytes in supercooled disaccharide aqueous solutions Longinotti, Maria Paula Corti, Horacio Roberto Carbohydrates Ceramic capacitors Dielectric waveguides Electric conductivity Electrolytes Ionization of liquids Ions Permittivity Polysaccharides Sodium chloride Sugar (sucrose) Supercooling Viscosity Aqueous solutions Bulk solutions Dielectric constants Dielectric friction Diffusion of water Effective dielectric constants Electrical conductivity Ion-ion interaction Ionic sizes Ionic solutes Molar conductivities Trehalose aqueous solutions Solutions The electrical conductivity of CsCl, KCl, Bu4NBr, and Bu 4NI was studied in stable and supercooled (metastable) sucrose and trehalose aqueous solutions over a wide viscosity range. The results indicate that large positive deviations from the Walden rule occur in these systems due to the higher tendency of the ions to move in water-rich regions, as previously observed for NaCl and MgCl2. The electrical molar conductivity viscosity dependence can be described with a fractional Walden rule (Ληα = constant), where α is a decoupling parameter which increases with ionic size and varies between 0.61 and 0.74 for all of the studied electrolytes. Using the electrical molar conductivity dependence of ion-ion interactions, an effective dielectric constant was calculated for a trehalose 39 wt% aqueous solution as a function of temperature. Above 278 K, the effective and the bulk solution dielectric constants are similar, but at lower temperatures, where the carbohydrate becomes less mobile than water, the effective dielectric constant approaches the dielectric constant of water. We also conclude that the solute-solvent dielectric friction contribution can be neglected, reinforcing the idea that the observed breakdown of the Walden rule is due to the existence of local microheterogeneities. The Walden plots for the studied ionic solutes show a decoupling similar to that found for the diffusion of water in the same solutions. © 2009 American Chemical Society. Fil:Longinotti, M.P. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Corti, H.R. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2009 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_15206106_v113_n16_p5500_Longinotti http://hdl.handle.net/20.500.12110/paper_15206106_v113_n16_p5500_Longinotti |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Carbohydrates Ceramic capacitors Dielectric waveguides Electric conductivity Electrolytes Ionization of liquids Ions Permittivity Polysaccharides Sodium chloride Sugar (sucrose) Supercooling Viscosity Aqueous solutions Bulk solutions Dielectric constants Dielectric friction Diffusion of water Effective dielectric constants Electrical conductivity Ion-ion interaction Ionic sizes Ionic solutes Molar conductivities Trehalose aqueous solutions Solutions |
| spellingShingle |
Carbohydrates Ceramic capacitors Dielectric waveguides Electric conductivity Electrolytes Ionization of liquids Ions Permittivity Polysaccharides Sodium chloride Sugar (sucrose) Supercooling Viscosity Aqueous solutions Bulk solutions Dielectric constants Dielectric friction Diffusion of water Effective dielectric constants Electrical conductivity Ion-ion interaction Ionic sizes Ionic solutes Molar conductivities Trehalose aqueous solutions Solutions Longinotti, Maria Paula Corti, Horacio Roberto Fractional Walden rule for electrolytes in supercooled disaccharide aqueous solutions |
| topic_facet |
Carbohydrates Ceramic capacitors Dielectric waveguides Electric conductivity Electrolytes Ionization of liquids Ions Permittivity Polysaccharides Sodium chloride Sugar (sucrose) Supercooling Viscosity Aqueous solutions Bulk solutions Dielectric constants Dielectric friction Diffusion of water Effective dielectric constants Electrical conductivity Ion-ion interaction Ionic sizes Ionic solutes Molar conductivities Trehalose aqueous solutions Solutions |
| description |
The electrical conductivity of CsCl, KCl, Bu4NBr, and Bu 4NI was studied in stable and supercooled (metastable) sucrose and trehalose aqueous solutions over a wide viscosity range. The results indicate that large positive deviations from the Walden rule occur in these systems due to the higher tendency of the ions to move in water-rich regions, as previously observed for NaCl and MgCl2. The electrical molar conductivity viscosity dependence can be described with a fractional Walden rule (Ληα = constant), where α is a decoupling parameter which increases with ionic size and varies between 0.61 and 0.74 for all of the studied electrolytes. Using the electrical molar conductivity dependence of ion-ion interactions, an effective dielectric constant was calculated for a trehalose 39 wt% aqueous solution as a function of temperature. Above 278 K, the effective and the bulk solution dielectric constants are similar, but at lower temperatures, where the carbohydrate becomes less mobile than water, the effective dielectric constant approaches the dielectric constant of water. We also conclude that the solute-solvent dielectric friction contribution can be neglected, reinforcing the idea that the observed breakdown of the Walden rule is due to the existence of local microheterogeneities. The Walden plots for the studied ionic solutes show a decoupling similar to that found for the diffusion of water in the same solutions. © 2009 American Chemical Society. |
| author |
Longinotti, Maria Paula Corti, Horacio Roberto |
| author_facet |
Longinotti, Maria Paula Corti, Horacio Roberto |
| author_sort |
Longinotti, Maria Paula |
| title |
Fractional Walden rule for electrolytes in supercooled disaccharide aqueous solutions |
| title_short |
Fractional Walden rule for electrolytes in supercooled disaccharide aqueous solutions |
| title_full |
Fractional Walden rule for electrolytes in supercooled disaccharide aqueous solutions |
| title_fullStr |
Fractional Walden rule for electrolytes in supercooled disaccharide aqueous solutions |
| title_full_unstemmed |
Fractional Walden rule for electrolytes in supercooled disaccharide aqueous solutions |
| title_sort |
fractional walden rule for electrolytes in supercooled disaccharide aqueous solutions |
| publishDate |
2009 |
| url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_15206106_v113_n16_p5500_Longinotti http://hdl.handle.net/20.500.12110/paper_15206106_v113_n16_p5500_Longinotti |
| work_keys_str_mv |
AT longinottimariapaula fractionalwaldenruleforelectrolytesinsupercooleddisaccharideaqueoussolutions AT cortihoracioroberto fractionalwaldenruleforelectrolytesinsupercooleddisaccharideaqueoussolutions |
| _version_ |
1768545112802983936 |