Thermodynamic parameters of electrolyte solutions in nitromethane

Standard enthalpies of solution of eighteen 1:1 electrolytes in nitromethane derived from heats of solution measured calorimetrically at 298 K are reported. Combination of these data and those in water yields enthalpies of transfer, ΔH°t, for these electrolytes from water to nitromethane. The Ph4AsPh4B convention has been used to derive single-ion ΔH°t contributions for seven cations and six anions. These data and those previously reported for single-ion free energy of transfer from water to nitromethane enables the calculation of the transfer single-ion entropies based on the Ph4AsPh4B convention. As in transfers from water to other non-aqueous solvents ΔS°t(M++ X–) from water to nitromethane is approximately independent of M+ and X– when M+= Li+, Na+, K+, Rb+ and Cs+ and X–= ClO–4, I–, Br– and perhaps Cl–. The results obtained indicate that ΔH°t for the alkali-metal cations between dipolar aprotic solvents derived from heat of complexing data of cryptand 222, and these cations in these solvents yield single-ion values for transfer among dipolar aprotic solvents that are chemically reasonable and in accord with values obtained by the Ph4AsPh4B convention.