The heat capacity and density of solutions of barium and tetrabutylammonium iodides in N-methylpyrrolidone at 298.15 K

Abstract

The heat capacity and density of solutions of barium and tetrabutylammonium iodides in N-methylpyrrolidone (MP) were studied at 298.15 K by calorimetry and densimetry. The standard partial molar heat capacities and volumes ( $$ \overline {C_{p^2 }^ \circ } $$ and $$ \overline {V_2^ \circ } $$ ) of the electrolytes in MP were calculated. The standard heat capacities $$ \overline {C_{pi}^ \circ } $$ and volumes $$ \overline {V_i^ \circ } $$ of the Ba2+ and (C4H9)4N+ ions in solution in MP at 298.15 K were determined. With the tetrabutylammonium ion, these values were in agreement with those calculated on the basis of the tetraphenylarsonium-tetraphenyl borate and tetraphenylphosphonium-tetraphenyl borate assumptions. The results are discussed in relation to the special features of solvation in solutions of the salts studied.