COSMO-RS helps connect solvent screening to real-world separation process design

Separating close-boiling or azeotropic mixtures is one of the persistent challenges in chemical engineering. Benzene and cyclohexane are a typical example: they are industrially important, difficult to separate by conventional distillation, and relevant to petrochemical and polymer production.

In this study, the authors show how molecular modeling can make solvent selection more rational. Instead of relying only on experimental trial and error, they use COSMO-RS in the Amsterdam Modeling Suite to screen ionic liquids for liquid-liquid extraction of benzene from cyclohexane. The screening narrows a broad solvent space to promising ionic liquid candidates by estimating thermodynamic properties linked to selectivity and solvent capacity.

The bigger picture is the connection between molecular design and process performance. COSMO-RS provides the first filter, identifying which ionic liquids are likely to extract benzene more effectively. The authors then combine this with molecular-level analysis, molecular dynamics, experimental liquid-liquid equilibrium data, and process simulation. This creates a workflow that links “Why does this solvent work?” with “Would this solvent make sense in a process?”

The result is a clear example of how modeling supports better R&D decisions. AMS helps reduce the search space, guide experimental effort, and connect molecular interactions to practical separation metrics such as energy use, cost, and CO₂ emissions. For challenging separations, this kind of integrated approach can help researchers move from solvent discovery toward process design with more confidence.