The α‐effect in micelles: Nucleophilic substitution reaction of p‐nitrophenyl acetate with N‐phenylbenzohydroxamate ion

Abstract

Pseudo-first-order rate constants have been determined for the nucleophilic substitution reactions of p-nitrophenyl acetate with p-chlorophenoxide (4-ClC 6 H 4 O − ) and N-phenylbenzohydroxamate (C 6 H 5 CON(C 6 H 5 )O − ) ions in phosphate buffer (pH 7.7) at 27 • C. The effect of cationic, (CTAB, TTAB, DTAB), anionic (SDS), and nonionic (Brij-35) surfactants has been studied. The k obs value increases upon addition of CTAB and TTAB. The effect of DTAB and other surfactants on the reaction is not very significant. The micellar catalysis and α-effect shown by hydroxamate ion have been explained.

Kinetic study of the reactions of p‐nitrophenyl acetate and p‐nitrophenyl benzoate with oximate nucleophiles

“…It is well known that micelles and similar colloidal assemblies generally increase the nucleophilic reactivity 20–25. The structure and properties of surfactants play an important role in determining chemical reactivity.…”

Reactions of Carboxylic, Phosphoric and Sulfonic Acids and their Derivatives

“…66 In a wider study, the effect of cationic, anionic, and non-ionic surfactants on the reactivity towards pnitrophenyl acetate of the α-nucleophile N -phenylbenzohydroxamate, PhC(O)N(Ph) O − , at pH 7.7 was reported. 67 p-Nitrophenyl picolinate (49) has been studied in three reports. In the first, complexes of Ni(II) with dioxocyclam (50) increased the rate of hydrolysis of (49) some 3000-fold in the presence of a variety of surfactants, n-lauroylsarcosine sodium proving the most potent.…”

Comparative study of nucleophilic efficacy of pralidoxime towards phosphorus, sulfur and thiophosphorus based esters

“…A number of schemes have been studied to improve the hydrolysis of phosphoester and carboxylate esters, and these include the presence of enzymes, metals, metallomicelles and nanoparticles etc. [13][14][15][16][17]. Cationic micelles accelerate the rate of hydrolysis of such compounds via micellar catalysis [18][19][20][21].…”