Carbon dioxide (CO2) Capture from post-combustion industrial effluents will substantially contribute to the reduction of anthropogenic emission of carbon responsible for global warming. The chemical absorption of CO2 in mixed solvents (typically aqueous solution of alkanolamines [1]) is considered as a promising avenue for its capture before transportation and storage [2]. Research projects are developed in order to reduce the energy costs of the regeneration step in process working on absorption-desorption cycles. CO2 desorption requires substantial heating of the whole system containing the products resulting from chemical reactions of CO2. This presentation concerns the use of demixing amines to reduce of the energy involved in capture process. These amines show a liquid-liquid phase separation at moderately elevated temperatures [3]. Such a phase separation occurring at the output of the absorber unit will concentrate carbon in water rich phase that is the only part of the solvent that needs to be regenerated. The presentation will focus on the study of those phase separations for water + amine mixtures. It is proposed to investigate a group of piperidine derivatives and to analyse the effect of substitution in different positions on the ring. First measurements will also be reported for evaluating the influence of CO2 on the temperature of liquid-liquid phase separation. The phase diagrams will be obtained in combining two different methods. A microcalorimeter from setaram was used to determine the liquid-liquid separation temperature. The calorimeter is based on calvet principle and is able to operate in scanning temperature mode from 253 K to 393 K. it allows to measure the differential thermal flux between the measuring cell filled with the solution and the reference cell filled with water as reference fluid. The liquid-liquid separation temperature is determined by evaluating the first point when the thermal flux diverges from the baseline. Simultaneously to these calorimetric measurements, a phase equilibrium cell was developed to get optical information on the liquid-liquid separation. The binary solution was introduced in the cell, and the solution was observed during scanning of temperature. The scanning rate chosen was similar to calorimetric measurements in order to be able to compare directly the results. The separation temperature was noted when the first turbidity is observed. REFERENCES [1] L. Rodier, K. Ballerat-Busserolles, J-Y. Coxam, J. Chem. Thermodynamics, 42, 773-780 (2010). [2] L. Raynal, P-A. Bouillon, A. Gomez, P. Broutin, Chemical Engineering Journal, 10.1016/j.cej.2011.01.008 [3] Y. Coulier, K. Ballerat-Busserolles, L. Rodier, J-Y. Coxam, Fluid Phase Equilibria, 296, 206-212 (2010)