Solubility and diffusivity of CO2 and C2H4 in the ionic liquids 1-alkyl-2,3-dimethylimidazolium bis(trifluoromethanesulfonyl)imide by tube-in-tube reactor method

Abstract

In this paper, the solubility and diffusivity of CO2/C2H4 in ionic liquids 1-Ethyl-2,3-dimethylimidazolium Bis(trifluoromethanesulfonyl)imide([Emmim][Tf2N]), 1-Propyl-2,3-dimethylimidazolium Bis(trifluoromethanesulfonyl)imide([Pmmim][Tf2N]), 1-Butyl-2,3-dimethylimidazolium Bis(trifluoromethanesulfonyl)imide([Bmmim][Tf2N]) and 1-Hexyl-2,3-dimethylimidazolium Bis(trifluoromethanesulfonyl)imide([Hmmim][Tf2N])) are measured at the temperature range of 303–333 K with a tube-in-tube reactor. The new device can greatly decrease the measurement time to several minutes in the tube-in-tube reactor. The solubility data is determined by the steady-state method with less than 10% deviation compared with previous reports. The diffusivity data is measured by an unsteady-state method within 3 min. The diffusion coefficient of CO2 in ionic liquids can be predicted with Morgan’s diffusivity correlation equation. For the diffusivity of C2H4 in ionic liquids, an empirical formula is developed and the predicted values using this correlation agree well with measured values with less than 17% deviation. The measured solubility and diffusivity data of CO2/C2H4 in ionic liquids and corresponding correlations can help to develop a more efficient process involving CO2/C2H4/ionic liquids system.