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Phase change absorbents have recently drawn increasing attention due to the potential of for low energy-consuming CO2 capture. When forming two phases after CO2 absorption, only the CO2-rich phase is heated in the desorption process thus reducing the sensible heat. In this work, five amine and three alcohol blends were used to investigate their phase change behavior after reacting with CO2. Phase separation could easily occur for DETA/alcohol/water combinations after CO2 absorption, which was confirmed by the large difference of the solvation free energy in alcohol and in water (i.e. DETA-CO2 has 12.5 kcal/mol ΔGsol in 1-propanol less than that in water). The optimization of the DETA/1-propanol/H2O solution was confirmed to be 30% DETA + 30% 1-propanol + 40% H2O (D30P30H40). It was found that above 90% of CO2 loading was enriched in lower phase. 13C NMR spectrum indicated that carbamate and bicarbonate was formed in lower phase and 1-propanol acted as a good physical solvent to trigger phase separation and facilitate the reaction between amine and CO2.