Alkylimidazolium-based ionic liquids with tailored anions and cations for CO2 capture

Abstract

A systematic investigation was conducted in the present study to determine how various cations and anions affected the solubility of CO₂. To investigate the influence of different cations and anions on the solubility of CO₂, twelve ILs were synthesized, characterized, and utilized. These ILs comprised five distinct anions (dioctylsulfosuccinate [DOSS], triflouromethanesulfonate [TFMS], dodecylsulfate [DDS], 3-sulfobezoate [SBA], and benzene sulfonate [BS]), and four distinct cations (1-butyl-3-propanenitrile imidazolium [C₂CN Bim], 1-hexyl-3-propanenitrile imidazolium [C₂CN Him], 1-octyl-3-propanenitrile imidazolium [C₂CN Oim], and 1-decyl-3-propanenitrile imidazolium [C₂CN Dim]). The synthesized ILs were characterized using NMR and elemental analysis. Their moisture and halide contents were determined. The gravimetric method (MSB) was employed to determine the solubility of CO₂ at various pressures (20, 15, 10, 5, and 1 bar). In addition, the effects of temperature on the solubility of CO₂ were investigated. The constant of Henry's law (k_H) was also calculated, along with thermodynamic properties including standard enthalpy (H⁰), entropy (S⁰), and Gibbs free energy (G⁰).