The integration of COSMO-RS methodology to Aspen Tech's process simulators is used in this work to elaborate new criteria for the design/selection of ionic liquids to specific applications. These criteria are related to the operating conditions and energetic consumptions being the procedure capabilities demonstrated through the example of the IL regeneration in separation processes. Previously, the predictive capacity of the COSMO-RS method respect to VLE of mixtures (organic solvent + IL) is assessed and the correct transferability of the COSMO-RS results to Aspen Plus/Aspen HYSYS process simulators demonstrated. (c) 2012 Elsevier B.V. All rights reserved.