Ionic contributions to the viscosity B coefficients of the Jones–Dole equation. Part 5.—Acetonitrile

Abstract

The B coefficients of the Jones–Dole viscosity equation are a measure of the size of the ions and of the interaction between the ions and the solvent. The B coefficients have been determined for the electrolytes Bu₄NBu₄B, Bu₄NBr, Bu₄NI, Ph₄PBr, Ph₄PI, NaI and NaPh₄B, and for the homologous series from Et₄NBr to Hept₄NBr in acetonitrile at 25 and 35 °C. Ionic B values for the bromide and iodide ions have been calculated from the B coefficients for the tetra-alkylammonium solutions and are compared with those obtained from the tetraphenylphosphonium solutions. The transition-state treatment has been applied to the results, and the thermodynamic activation parameters for viscous flow have been calculated. These are compared with those found previously for solutions of dimethyl sulphoxide, hexamethylphosphoric triamide and N,N-dimethylformamide, and are discussed in terms of the new theory of B coefficients proposed by Feakins.