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The solubilities of CO 2 in eutectic mixtures containing choline chloride and dihydric alcohols (including 1,4-butanediol, 2,3-butanediol, and 1,2propanediol) with a molar ratio of choline chloride to dihydric alcohol of 1:3 and 1:4 were measured at 293.15 K, 303.15 K, 313.15 K, and 323.15 K under pressures up to 600.0 kPa using an isochoric saturation method. Henry's constant and the dissolution Gibbs free energy, enthalpy, and entropy changes of CO 2 solvation were obtained by correlating the experimental data. The solubility of CO 2 in the mixtures increased linearly with the increasing pressure or the decreasing temperature. The enthalpies of solution were negative at all conditions.

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1-allyloxy-3-(4-nonylphenoxy)-2-propanol polyoxyethylene ethers (ANAPEs), a new type of absorbent, are polymeric surfactants with different adduct numbers. In this work, ANAPEs, including SN-10 with adduct number of 10 and SN-15 with adduct number of 15, were prepared for CO 2 absorption using the isochoric saturation method. Densities of the ANAPEs at atmospheric pressure were measured by a 5.567 ± 0.004 cm 3 pycnometer, which decreased with increased temperature. Solubility data of CO 2 in ANAPEs were measured within the pressure range of 0 - 600.0 kPa and temperature range of 303.15 - 323.15 K at 10 K intervals and could be calculated on the basis of experimental data of p, x CO2 and b CO2 . The solubility of CO 2 in absorbents increased linearly with increasing pressure and decreased with increasing temperature at all the pressures. The solubility of CO 2 in SN-15 is the highest at all temperatures, but almost the same with SN-10 at 303.15 K over pressures (p < 350kPa), which indicates physical dissolution process. Henry's constants were determined from solubility data. With increasing temperature, Henry's constants increased. Thermodynamics of CO 2 absorption were calculated including enthalpy, entropy, and Gibbs energy. The absolute value of Δ sol H based on H x of SN-15 is largest at 303.15 K and indicates stronger SN-15/CO 2 interactions, consistent with solubility of CO 2 based on H x . The negative enthalpy demonstrated exothermic process, which means the dissolution of CO 2 in ANAPEs is favourable enthalpically. The Δ sol G shows positive value.