Micellar Catalysis of Dephosphorylation by Benzimidazolide and Naphth-2,3-imidazolide Ions

Article abstract of DOI:10.1021/ja00409a028

The reactions of p-nitrophenyl diphenyl phosphate (p-NPDPP) with benzimidazolide and naphth-2,3-imidazolide ion are strongly catalyzed by micelles of cetyltrimethylammonium bromide (CTABr).The maximum rate enhancements are 2.5E3 and ca. 1.5E4 for benzimidazole and naphth-2,3-imidazole, respectively.The first-order rate constants go through maxima with increasing , and for > 1E-3 M the rate-surfactant profile is accomodated by a pseudophase model which relates rates in the micelles to the concentrations of micellar bound reactants, with the second-order rate constants in the micelle being similar to those in water.The imidazolide ions are phosphorylated by p-NPDPP and the phosphoryl intermediates can react with p-nitrophenoxide ion, regenerating starting material, or can go forward to product.