'Reverse Micellar Aggregates' in Phase Transfer Catalyzed Nucleophilic Displacement Reactions

Abstract

According to the 'extraction mechanism' for 'normal phase transfer catalysis' the reaction is taking place at the organic phase into which the anion is transferred by phase transfer catalyst (PTC) in the form of individual ion-pairs. However, this mechanism is still a matter of discussion and remains a subject of some controversy. Herein, an alternate explanation for the reaction which raises the formation of aggregates resembling reverse micelles in organic media is described. NMR studies on the structural dynamics of HTPB in solution and, correlation study between the structures of catalyst and reactant offered evidences for aggregation of PTC in organic media. More evidences are obtained from studies on the kinetics of reaction at two temperatures and role of traces of water in formation of micelles. The above studies were done for cyanide displacement reactions of 1-chlorooctane and benzyl halides. Moreover, SNAr reaction of Sanger's reagent with carbon nucleophile has provided qualitative support on the aggregation of PTC's in organic medium