A study of activation parameters for viscous flow process of some tetraalkylammonium salts in binary mixtures of N,N-dimethylformamide and ethyl methyl ketone

摘要

Viscosities and densities of tetrabutylammoniumtetraphenylammonium boride ( Bu_4NBPh_4), tetrabutylammonium bromide (Bu_4NBr_4), tetrapentylammonium bromide (Pen_4NBr), tetrahexylammonium iodide (Hex_4NI), sodium tetraphenyl boride (NaBPh_4) and sodium iodide (NaI) in ethyl methyl ketone (EMK), N,N-dimethyl formamide (DMF) and EMK + DMF solvent mixtures containing 0, 20, 40, 60, 80 and 100 mol % of EMK in the concentration range (0.02-0.1) mol dm~(-3) at 25, 35, and 45 deg C have been reported. The viscosity data have been analyzed in terms of A- and B- viscosity coefficients of the Jones-Dole equation. Both A- and B-coefficients have been found to be positive over the entire solvent composition range at all temperatures. The B-coefficients have been resolved into B_(+-) ionic coefficients using Bn_4NBPh_4 assumptions. The B_(+-) values of tetraalkylammonium ions are found to be positive. Partial molal volumes (V~O_2) have also been calculated which have been used along with B-values to calculate activation parameters for viscous flow process of electrolytic solutions. The activation parameters have been examined as a function of solvent composition to interpret the solution behaviour of these tetraalkylammonium salts in EMK-DMF mixtures.