High-pressure phase behavior of ternary mixtures with ionic liquids, part I: The system bmim[BF₄]+4-isobutylacetophenone + CO₂

Performing reactions in a homogeneous system is extremely important for the achievement of high reaction rates and yield. Since carbon dioxide can tune the miscibility of ionic liquid/organic mixtures, measurements on the phase behavior of these systems provide useful information for the selection of operational conditions for reactions and extractions. We investigated the phase behavior of ternary mixtures of the type bmim[BF₄] + solute + CO₂, in which the solute is an intermediary in the synthesis of ibuprofen. In this contribution, the influence of carbon dioxide pressure on the location of the homogeneous liquid phase region in the phase diagram of the ternary system bmim[BF₄] + 4-isobutylacetophenone + CO₂ is presented. We show that for CO₂ concentrations above 60 mol%, a narrow three-phase region can be found in the pressure versus temperature diagram, and that a further increase in CO₂ composition gradually reduces the extension and influences the location of the one-phase liquid region, finally resulting in its complete disappearance.