New VLE ebulliometric data for binary aqueous 2-amino-2-methyl-1-propanol (AMP) and piperazine (Pz) solutions and ternary aqueous AMP/Pz solutions are reported at different temperatures and concentrations. A proposed combination of titration and a H-1-NMR technique was developed and determination of the composition of the ternary system was successfully carried out. Results show that AMP is more volatile than commercial solvents such as MEA and MDEA whereas Pz is observed to be less volatile than that of MEA and MAPA. Three thermodynamic models (NRTL, Wilson and UNIQUAC) were used to correlate the data and the determined interaction parameters for both the binary and ternary VLE systems are given. New binary interaction parameters for (AMP(1) and Pz(2)) are also proposed. However, the parameters have no statistical significance which indicates that the activity coefficients for the species in the ternary system in general are similar to the activity coefficients obtained from the corresponding binary mixture. More data may be required for ternary VLE estimation, especially at higher amine concentrations. (c) 2013 Elsevier Ltd. All rights reserved.