Synthesis, thermophysical properties and CO2 sorption of imidazolium, thiazolium, iminium and morpholinium-based protic ionic liquids paired with 2-acrylamido-2-methyl-1-propanesulfonate anion

Abstract The present study aims to investigate the temperature dependence of the physicochemical properties of four cations (namely 2-chloro-1,3-dimethylimidazolium [diMeim], 3-benzyl-5-(2-hydroxyethyl)-4-thiazolium [bnthia], (chloromethylene)dimethyl iminium [diMeimi] and morpholinium [mrph]) paired with common 2-acrylamido-2methyl-1-propanesulfonate [AMPS] anion. The density and viscosity of the resulting ionic liquids (ILs) were measured within temperature range of (293.15–363.15) K while refractive indexes were determined within temperature range of (288.15–333.15) K. Among the investigated novel ILs, [bnthia][AMPS] showed the highest viscosity and density over the entire temperature range and an enhanced CO2 dissolution of 0.65 mol fraction was observed at 1 MPa and 298.15 K. Furthermore, the Henry's constant of [bnthia][AMPS] was found to be 1.199 MPa which was 23.7, 32.6, and 56.0% less than [diMeim][AMPS], [diMeimi][AMPS] and [mrph][AMPS], respectively. The present study provides a detailed insight to understand structure-activity relation between physicochemical properties and CO2 solubility of studied ILs.