Enzymatic Membrane Reactor for Resolution of Ketoprofen in Ionic Liquids and Supercritical Carbon Dioxide

Ionic liquids (ILs) have attracted growing interest as alternative reaction media for enzyme-catalyzed transformations because of their unique properties as green solvents, opening up news opportunities in the field of pharmaceutical synthesis. Additionally, enzymatic transformations in ILs/scCO(2) biphasic systems have been described as an interesting way of carrying out clean synthetic processes whereby enzyme molecules are "immobilized" into the IL phase, while substrates/products are transported by the scCO(2) phase. Several ILs based on alkyl-imidazolium cations and associated with different anions, ([PF6], [BF4] and [NTf2]), have been assayed for the Candida antarctica lipase B (CALB)-catalyzed resolution of the analgesic rac-ketoprofen by esterification with different 1-alkanols. A membrane reactor working with both IL and supercritical carbon dioxide (scCO(2)) phases has been applied for separation of R-ketoprofen ester products.