Solubility Behavior of CO₂ in Ionic Liquids Based on Ionic Polarity Index Analyses

Area of Science:

• Materials Science
• Chemical Engineering
• Physical Chemistry

Background:

• Ionic liquids (ILs) are versatile solvents for CO2 capture.
• A vast number of IL compositions necessitate efficient screening methods.
• Existing methods for IL property characterization can be time-consuming.

Purpose of the Study:

• To introduce and validate the ionic polarity index (IPI) for ILs.
• To establish correlations between IPI and CO2 volumetric solubility.
• To enable rapid prescreening of ILs for enhanced gas solvation.

Main Methods:

• Calculation of ionic polarity index (IPI) for IL anions and cations.
• Development of correlations linking IPI with experimental CO2 solubility data.
• Analysis of IPI applicability across homologous series of ILs.

Main Results:

• The ionic polarity index (IPI) effectively correlates with CO2 volumetric solubility in ILs.
• Established relationships are generally applicable within homologous IL series.
• IPI provides a single metric for rapid IL property assessment.

Conclusions:

• The ionic polarity index (IPI) is a valuable tool for prescreening ILs.
• IPI facilitates the identification of ILs with high CO2 solvation performance.
• This approach accelerates the development of efficient CO2 capture solvents.