Enthalpy of absorption and limit of solubility of CO2 in aqueous solutions of 2-amino-2-hydroxymethyl-1,3-propanediol, 2-[2-(dimethyl-amino)ethoxy] ethanol and 3-dimethyl-amino-1-propanol at T = 313.15 K and 353.15 K and pressures up to 2 MPa.
Résumé
In order to study the influence of amine structure on absorption of carbon dioxide, enthalpies of solution of CO2 in 2.50 mol.L-1 aqueous solutions of 2-amino-2-hydroxymethyl-1,3-propanediol (THAM), 2-[2-(dimethyl-amino)ethoxy] ethanol (DMAEOE) and 3-dimethyl-amino-1-propanol (DMAP) were measured. The enthalpies of solution are determined as function of gas loading charge (moles of CO2/mole of amine), at temperatures 313.15 K and 353.15 K, and pressures range from 0.5 MPa to 2 MPa. Measurements are carried out using a flow calorimetric technique. CO2 solubilities in the aqueous solutions of amine are derived from calorimetric data. Molar volumes of aqueous amine solutions required to handle calorimetric data were determined at 303.15 K using a vibrating tube densimeter. Experimental enthalpies of solution are discussed on the basis of amines alkalinity.