Micelles of deprotonated 1-cetyl-3-(2-oximopropyl)imidazolium chloride strongly accelerate displacements of 4-nitrophenoxide ion from 4-nitrophenyl diethyl phosphate and 4-nitrophenyl tosylate. The first-order rate constants of reactions of fully bound substrates are similar to those predicted from second-order rate constants of reactions of deprotonated 1-methyl-3-(2-oximopropyl)imidazolium chloride in water and a reasonable value of the molar volume of the micellar interfacial region.