Thermodynamic properties of CO2 absorption in hydroxyl ammonium ionic liquids at pressures of (100–1600) kPa

Solubility of CO2 in six hydroxyl ammonium ionic liquids 2-hydroxyethanaminium acetate [hea],
bis(2-hydroxyethyl)ammonium acetate [bheaa], 2-hydroxy-N-(2-hydroxyethyl)-N-methylethanaminium
acetate [hhemea], 2-hydroxyethanaminium lactate [hel], bis(2-hydroxyethyl)ammonium lactate [bheal],
2-hydroxy-N-(2-hydroxyethyl)-N-methylethanaminium lactate [hhemel] at temperatures (298.15,
313.15, and 328.16) K and pressures ranging from (100 to 1600) kPa was determined. From the experimental
solubility data, the Henry’s constant of CO2 for each hydroxyl ammonium ionic liquids was estimated
and reported as a function of temperature. Furthermore, enthalpy and entropy of absorption were obtained
from estimated Henry’s constant. The results showed that the solubility increase with increasing pressure
and decrease with increasing temperature and the solubility of CO2 in these six hydroxyl ammonium ionic
liquids was in sequence: [hea] > [bheaa] > [hel] > [bheal] > [hhemel] > [hhemea].