In this work, CO2 absorption capacities in a series of aqueous N-alkyl-N-methylmorpholinium-based ILs with acetate as the counterpart anion were investigated. Among these ILs, N-butyl-N-methylmorpholinium acetate ([Bmmorp]­[OAc]) with the highest CO2 absorption capacity was screened for thermodynamic modeling. The non-random two-liquid model and the Redlich–Kwong equation of state (NRTL-RK model) were used to describe the phase equilibria. The CH4 absorption capacity in the aqueous [Bmmorp]­[OAc] was also measured in order to verify the results predicted from the thermodynamic modeling, and the comparison shows the reliability of the model prediction. The parameters were embedded into the commercial software Aspen Plus. After that, the aqueous [Bmmorp]­[OAc] solutions with 30–40 wt % of water were selected to carry out process simulation for CO2 separation from biogas, and it was found that using these aqueous [Bmmorp]­[OAc] gave rise to lower energy usage and smaller size of equipment than other physical solvents. The results suggest that aqueous [Bmmorp]­[OAc] solution can be used as an alternative to organic solvents and has the potential to decrease the cost of CO2 separation.

In this work, aqueous 1‐allyl‐3‐methylimidazolium formate ([Amim][HCOO]) was studied as a potential sorbent for CO2 separation. The density and viscosity of aqueous [Amim][HCOO] were measured at temperatures ranging from 293.15 to 333.15 K at atmospheric pressure. The solubility of CO2 and CH4 in dry [Amim][HCOO] as well as the CO2 solubility in aqueous [Amim][HCOO] were measured at pressures up to 1.8 MPa and temperatures of 298.2, 313.2, and 333.2 K. The results showed that the density and viscosity of aqueous [Amim][HCOO] as well as the CO2 solubility in aqueous [Amim][HCOO] decreased upon increasing the water concentration and temperature. The viscosity was very sensitive to the water concentration. The experimental density and viscosity of aqueous [Amim][HCOO] were fitted to semiempirical equations, and the excess molar volume and viscosity deviations were calculated to investigate the interaction between the [Amim][HCOO] ionic liquid and water. The experimental vapor–liquid equilibrium was represented with the nonrandom two‐liquid and Redlich–Kwong model. The model parameters can be further implemented into Aspen Plus software to conduct process simulations.

Herein, we have studied the potential of lutidinium-based ionic liquids in the dissolution of cellulose as confirmed by the X-ray diffraction (XRD), scanning electron microscopy (SEM) and 13C CP/MAS NMR, spectroscopic methods.