(762c) Kinetic Evaluation of Novel Functionalized Phase Transfer Catalysts

Phase transfer catalysis (PTC) is a means of enabling contact between reactive species that are dissolved in immiscible phases.  PTC is frequently employed in organic syntheses of pharmaceutical and specialty chemical products.  The most common class of phase transfer catalysts are quaternary ammonium salts, which can partition between aqueous and organic phases to facilitate reaction.  A new protocol employing thiolene “click” chemistry allows the synthesis of quaternary ammonium salts of varied functionalization to form novel phase transfer catalysts.  In this work, reaction rates of second-order nucleophilic substitutions between inorganic salts and organic halides using these novel catalysts are measured.  Kinetic parameters, including rate constants and activation energies, are evaluated.  The catalytic activity is compared to those using their more traditional analogues.   Additionally, the effects of polar and nonpolar functionalization on the partitioning of the catalysts between water and organic solvents and the influence of the partitioning on the reaction rates are investigated.