Publicação
Shape effects in the partial molar volume of tetraethylphosphonium and ammonium iodides in six nonaqueous solvents
| Resumo: | Densities of dilute solutions of the electrolytes tetraethylphosphonium iodide and tetraethylammonium iodide in the nonaqueous solvents methanol, ethanol, 1-propanol, 1-butanol, acetonitrile, and 2-propanone were measured at 25degreesC. Using published values for the Debye-Huckel limiting slopes A(V), apparent molar volume data were fitted to the Pitzer equation yielding infinite-dilution partial molar volumes (V) over bar (infinity)(i) deviation parameters B-V. It is found that the variation in the van der Waals volume of the cationic central atoms is about one half the experimental volume change in 2-propanone solutions, but twice that value in the other five solvents. This finding is interpreted in terms of openness of solute structure and solvent penetration. Parameter B-V for each salt is shown to be solvent dependent. An interesting approximate linear variation between A(V) and B-V parameters is suggested by the data. This empirical relationship would entail correlation of short- and long-range interionic interactions in solution. |
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| Autores principais: | Pinheiro, LMV |
| Outros Autores: | Calado, ART; Reis, JCR; Viana, CAN |
| Assunto: | Chemistry, Physical |
| Ano: | 2003 |
| País: | Portugal |
| Tipo de documento: | artigo |
| Tipo de acesso: | acesso a metadados |
| Instituição associada: | Universidade de Lisboa |
| Idioma: | inglês |
| Origem: | Repositório da Universidade de Lisboa |
| Resumo: | Densities of dilute solutions of the electrolytes tetraethylphosphonium iodide and tetraethylammonium iodide in the nonaqueous solvents methanol, ethanol, 1-propanol, 1-butanol, acetonitrile, and 2-propanone were measured at 25degreesC. Using published values for the Debye-Huckel limiting slopes A(V), apparent molar volume data were fitted to the Pitzer equation yielding infinite-dilution partial molar volumes (V) over bar (infinity)(i) deviation parameters B-V. It is found that the variation in the van der Waals volume of the cationic central atoms is about one half the experimental volume change in 2-propanone solutions, but twice that value in the other five solvents. This finding is interpreted in terms of openness of solute structure and solvent penetration. Parameter B-V for each salt is shown to be solvent dependent. An interesting approximate linear variation between A(V) and B-V parameters is suggested by the data. This empirical relationship would entail correlation of short- and long-range interionic interactions in solution. |
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