The excess molar enthalpies of binary and ternary working solutions containing ionic liquid

1-butyl-3-methylimidazolium dibutylphosphate

(1)+ CH3OH(2)/C2H5OH(2)/H2O(2)and(1)+ CH3OH(2)/C2H5OH(2)+ H2O(3)were measured with an adiabatic calorimeter at 298.15 K under the normal atmospheric pressure.The experimental excess molar enthalpies of binary working solutions were correlated with non-random two liquid(NRTL)activity coefficient model

and the binary interaction parameters were obtained.The average relative deviations between the correlated excess molar enthalpies and the experimental values for three binary solutions are 1.81%

1.44% and 0.72%.For the excess molar enthalpies of two ternary solutions predicted based on the binary interaction parameters

the average relative deviations between the predicted and the experimental excess molar enthalpies are 2.31% and 2.49%.The excess molar enthalpies for the binary solutions and the ternary solutions are negative in the whole range of IL concentration

so the mixing processes of[bmim] with water and methanol or ethanol are exothermic

which is one of the basic property of working solution in absorption cycles.