COSMO-descriptor based computer-aided ionic liquid design for separation processes: Part II: Task-specific design for extraction processes

- A computer-aided ionic liquid design (CAILD) strategy is developed.
- A mixed simulated annealing-genetic algorithm is presented to solve the MINLP problem.
- The CAILD strategy is tested by two examples of extraction process.

A computer-aided ionic liquid design (CAILD) framework is presented to identify optimal structures of ionic liquids (ILs) for specific separation processes. The design task is formulated as an optimization problem with the objective of maximizing the IL separation performance. In order to result in ILs with high practical application potential, constraints on their physicochemical properties are considered in CAILD. IL candidates are represented by rooted trees, which facilitate the prediction of their σ-profiles and cavity volumes from the COSMO-GC-IL method proposed in the first part of this work. A mixed simulated annealing-genetic algorithm (MSAGA) algorithm is developed and used for solving the optimization-based CAILD problem. The proposed CAILD framework is tested to design ILs for two extraction processes, i.e., separation of benzene-cyclohexane and heptane-thiophene. The result demonstrates that MSAGA can reliably and efficiently solve the problem and the finally identified ILs show improved separation performance than literature-reported ones.