Stimulation of CO2 solubility in reversible ionic liquids activated by novel 1-(2-aminoethyl piperazine) and bis (3-aminopropyl) amine

Enrichment in CO2 Absorption by 2-Methyl Piperazine-Activated Tertiary Amines, Physical Solvents, and Ionic Liquid Systems

One of the ever-demanding research fields is the development of new solvents with better properties for mitigation of CO₂ compared to existing solvents. This work reports the measurement and modeling of CO₂ solubility in newly proposed aqueous solvent blends of 2-methyl piperazine with N-methyldiethanolamine (MDEA), sulfolane (TMSO₂), and 1-butyl-3-methyl-imidazolium acetate ([bmim] [Ac]). The operating temperature and CO₂ partial pressure conditions chosen were 303.2-323.2 K and 2-370 kPa, respectively. Along with this, qualitative ¹³C NMR and FTIR analysis were also performed to consider the proposed reaction scheme. The experimental vapor-liquid equilibrium data were modeled by a modified Kent-Eisenberg equilibrium model. The equilibrium constants associated with 2-methyl piperazine (2-MPZ) and [bmim] [Ac] deprotonation and carbamate formation reactions were regressed to fit the experimental CO₂ solubility data. In addition, the CO₂ cyclic capacity and heat of absorption were evaluated for the aq (MDEA + 2-MPZ) blend.