Spectroscopic analysis of CO2 Solubility in DBU Ionic Liquids:
Synthesis, Experimental and COSMO-RS Study
Abstract
In this study, four DBU based ILs namely [DBU][Ac],
[DBU][TFA], [DBU][MSA] and [DBU][TFMSA]
(1,8-diazabicyclo[5.4.0]undec-7-ene as cation and acetate,
trifluoroacetate, methanesulfonate and trifluoromethanesulfonate as
anions) were synthesized for CO2 capture. The neat and dried ILs was
characterized by 1H NMR and 13C NMR spectroscopic methods. The
systematic analysis of CO2 solubility in ILs was performed at 10 bar, 15
bar and 20 bar pressure and at T=(303.15 and 313.15) K. Among the four
ILs, [DBU][Ac] showed highest CO2 sorption efficiency (0.7992
mol/mol IL at 20 bar pressure and at 303.15 K) due to the formation of
new compound during the absorption process. From the experimental data
(pressure-concentration-temperature), Henry’s constant (KH) was
predicted to calculate the absorption tendency of ILs. The sign and
magnitude of thermodynamic properties such as Henry’s constant (KH),
Gibbs free energy (ΔGo), enthalpy (ΔHo) and entropy (ΔSo) reveals the
CO2 sorption efficiency.