Investigation of Potential Azeotrope Breakers Using DFT and COSMO Approach

Area of Science:

• Physical Chemistry
• Computational Chemistry
• Materials Science

Background:

• Ionic liquids (ILs) are tunable solvents with potential applications in separation processes.
• Understanding the physicochemical properties of ILs is crucial for designing effective separation agents.
• The butanol-water azeotrope presents a challenge in separation and purification.

Purpose of the Study:

• To investigate various cation-anion combinations of ionic liquids for their potential as entrainers.
• To predict the performance of ionic liquids in the butanol-water system using computational methods.
• To identify a feasible entrainer for breaking the butanol-water azeotrope.

Main Methods:

• Density Functional Theory (DFT) calculations for quantum chemical parameters.
• COSMO-RS (Conductor-like Screening Model for Real Solvents) for sigma profiles and potentials.
• Activity coefficient at infinite dilution calculations for the butanol-water system.

Main Results:

• Evaluated COSMO volume and DFT-derived properties (HOMO/LUMO energies, energy gap, hardness, softness, electronegativity, electrophilicity, chemical potential) for diverse ILs.
• Generated sigma profiles and potentials for selected cations and anions using COSMO-RS.
• Determined activity coefficients at infinite dilution for the butanol-water system to assess nonideality.

Conclusions:

• Computational screening identified specific ionic liquid combinations with favorable properties for butanol-water separation.
• A feasible entrainer was proposed for breaking the butanol-water azeotrope, demonstrating the utility of the applied computational approach.