Carbon Capture and Storage (CCS) is one of the main options for CO2 mitigation. Post-combustion capture processes using amines are considered as one of the most adequate methods for CCS [1]. However, the cost of avoided CO2 is very high and must be significantly reduced. It has been shown that the solvent regeneration represents the major penalty of the post-combustion capture process. Thus, several groups are presently interested in the identification of new solvents with the aim to reduce the cost of the regeneration step. One example of these new solvents is demixing amines. The singularity of aqueous solutions of demixing amines is a liquid-liquid separation at a specific temperature and CO2 loading. Therefore, after gas dissolution, two phases can be obtained: the rich amine solution and the CO2 rich aqueous solution. In these conditions the energy of regeneration is reduced as only the phase containing CO2 is sent to the stripper unit. In the present study phase equilibrium properties are measured in order to develop models representative of the liquid-liquid equilibria (LLE) in systems {water - amine}. Thermodynamic measurements [2-4] for the system {water - amine - CO2} are also performed in order to determine the enthalpies of solution and the solubility limits for these systems. The first part of this work concerns the experimental determination of LLE [5]. The specific amines investigated were N-methylpiperidine, 2-methylpiperidine and 2,4,6-Tris-(dimethylaminomethyl)phenol. In order to correlate the experimental data, a model based on Gibbs energy, UNIQUAC, was used. This model is able to describe liquid-liquid equilibrium of mixtures with miscibility gaps [6]. In the second part, the heats of mixing of CO2 in aqueous solutions of amine systems were measured by flow calorimetric technique. The technique makes it possible simultaneous determination of the enthalpies of solution and solubility limits. A rigorous model has been developed in our laboratory [7] to correlate (vapor + liquid) equilibrium and enthalpy of solution of CO2 in aqueous amine solutions. This one is used in parallel with an electrolyte UNIQUAC model [8]. [1] L. Raynal, P-A. Bouillon, A. Gomez, P. Broutin, Chemical Engineering Journal, 10.1016/j.cej.2011.01.008 [2] L. Rodier, K. Ballerat-Busserolles, J-Y. Coxam, J. Chem. Thermodynamics, 42, 773-780 (2010). [3] H. Arcis, L. Rodier, K. Ballerat-Busserolles, J-Y. Coxam, J. Chem. Thermodynamics, 39, 878-887 (2007) [4] H. Arcis, L. Rodier, K. Ballerat-Busserolles, J-Y. Coxam, J. Chem. Thermodynamics, 40, 1022-1029 (2008) [5] Y. Coulier, K. Ballerat-Busserolles, L. Rodier, J-Y. Coxam, Fluid Phase Equilibria, 296, 206-212 (2010) [6] I. Nagata, T. Meyer, J. Gmehling, Fluid phase Equilibria, 65, 19-39 (1991) [7] H. Arcis, L. Rodier, K. Ballerat-Busserolles, J-Y. Coxam, J. Chem. Thermodynamics, 41, 783-789 (2009) [8] K. Thomsen, P. Rasmussen, Chemical Engineering Science, 54, 1787-1802 (1999)