Jointlypublished by Elsevier Science B.V., Amsterdam and Ak-'ad~miai Kiad6,Budapest RKCL2871 React.Kinet. Catal.Lett. Vol. 61, No. 1,193-199 (1997) EFFECT OF MICELLES ON THE ACID HYDROLYSIS OF N-PI:IENYLBENZOHYDROXAMIC ACID Kallol K. Ghosh ~ and Santosh K. Sar a School of studies in Chemistry, Pt. Ravishankar Shulda University, Rajput (M.P.) 492 010 India, ~ Bhilai Institute of Technology, Bhilai, India Received August 14, 1995 In revised form May 23, 1996 Accepted September 16, 1996 Abstract The effect of cationic (cetylpyridinium bromide and cetylpyridinium chloride) anionic (sodium dodecyl sulfate and lithium dodecyl sulfate) and non-ionic (Brij-35 and Triton-X-100) micelles on the acid-catalyzed hydrolysis of N- phenylbenzohydroxamic acid in 20 vol.% dioxane medium, has been investigated. The kinetic results are explained by both pseudo-phase and Piszkiewicz cooperativity models. Keywords: Mieellar catalysis, N-phenylbenzohydroxamic acid, acid hydrolysis, surfaetants INTRODUCTION Substantial interest has been developed in the kinetics and mechanism of many organic reactions in micelles as a means of controlling the rates of reactions of chemical, industrial and biological interest. Particularly, hydrolysis of esters, amides and anilides have received great attention. However, we are still far from understanding micellar hydrolysis ofhydroxamic acids [1-5]. In,the present study, we report the acid (0.76 M HCI) hydrolysis of N- phenylbenzohydroxamic acid C6HsC(O)N(OH)C6H5 m 20 vol.% dioxane medium in the presence of three different kinds of surfactants: cationic (cetylpyridinium bromide, CPB, and cetylpyridinium chloride, CPC, 0133-1736/97AJS$12.00. 9 Akad6miai Kiad6, Budapest. All fights reserved.