Solubility of CO2 in room temperature ionic liquid [hmim][Tf2N]

Area of Science:

• Physical Chemistry
• Chemical Engineering
• Materials Science

Background:

• Ionic liquids are promising solvents for gas separation.
• Accurate solubility data is crucial for process design.
• 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide is a common ionic liquid.

Purpose of the Study:

• To measure carbon dioxide solubility in 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide.
• To validate an equation-of-state (EOS) model for this system.
• To investigate potential phase immiscibility.

Main Methods:

• Gravimetric microbalance used for solubility measurements.
• Temperatures from 282 K to 348 K and pressures up to 2 MPa.
• Comparison of experimental data with EOS model predictions and literature data.

Main Results:

• Solubility data for two different ionic liquid samples were nearly identical.
• The EOS model accurately correlated the experimental solubility data.
• EOS model predicted partial immiscibility, which was experimentally confirmed.

Conclusions:

• The studied ionic liquid exhibits predictable CO2 solubility behavior.
• The EOS model is reliable for predicting solubility and phase behavior.
• Partial immiscibility in CO2-rich solutions was confirmed, important for separation processes.