(590a) Solubility of Fluorinated Compounds in Room-Temperature Ionic Liquids | AIChE

(590a) Solubility of Fluorinated Compounds in Room-Temperature Ionic Liquids


Shiflett, M. B. - Presenter, DuPont Company

For any applications with a new type of solvents such as room-temperature ionic liquids (RTILs), knowledge of phase behaviors with various chemicals is essential. We have studied vapor-liquid equilibria (VLE) and liquid-liquid equilibria (LLE)) of industrially important fluorinated compounds in a variety of RTILs. Examples of chemicals include: chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs), fluorocarbons (FCs), hydrofluoroethers (HFEs) and fluorinated benzenes. VLE data have been measured with a gravimetric microbalance and successfully correlated with a modified Redlich-Kwong equation of state (EOS). The present EOS predicts partial immiscibilities (VLLE) with lower critical solution temperatures (LCSTs) in the solute-rich side solutions and indicates the Type-V mixture behavior (based on the Konynenburg-Scott classification) for many systems studied here. In order to verify our EOS predictions, we have conducted experiments to show VLLE for some selected binary systems. VLLE data have been obtained using a ?volume-mass-measurement? method at an isothermal condition, combined with a cloud-point method. This behavior is quite interesting, and in contrast with ionic liquid solutions of various alcohols and dialcohols, where immiscibility gaps have been well studied experimentally and show upper critical solution temperatures (UCSTs). In this report, we are particularly interested in understanding the global phase behavior of HFCs with ionic liquids and how this provides the basis for developing applications such as absorption cooling and extractive distillation.