Experimental measurement and Kent-Eisenberg modelling of CO2 solubility in aqueous mixture of 2-amino-2-methyl-1-propanol and hexamethylenediamine

• Measurement of equilibrium CO2 solubility in aqueous (hexamethylenediamine (HMDA)+2-amino-2-methyl-1-propanol(AMP)).
• Modelling CO2 solubility data using Kent-Eisenberg approach.
• Measurement of aqueous (HMDA+AMP) solvent density.
• Modelling density data using Redlich-Kister approach.
• Density and solubility model predicted results show AAD of 0.05% and 7.2% with the experimental data respectively.

In this work, vapour-liquid equilibrium of CO2 in aqueous mixture of 2-amino-2-methyl-1-propanol (AMP) and hexamethylenediamine (HMDA) is studied in the temperature and pressure range of 303.15–333.15 K and 1–100 kPa respectively. Concentration of the aqueous solutions used are (5mass% HMDA+25mass% AMP), (10 mass% HMDA+20 mass% AMP), (15mass% HMDA +15mass% AMP) and (20 mass% HMDA+10 mass% AMP). Density of aqueous amine solution is also measured in the same range of temperature and concentration. Redlich-Kister equation for excess molar volume is used to model density of the mixed solvent system. To correlate experimental CO2 solubility data, Kent and Eisenberg thermodynamic model is used. Equilibrium constants of bicarbamate formation reaction of HMDA and deprotonation reaction of AMP are regressed to fit experimental data with the model expression. Kent and Eisenberg model is found to predict the CO2 solubility in aqueous (HMDA + AMP) with good accuracy (AAD: 7.2%).