Effects of nonionic micelles on the rate of alkaline hydrolysis of N-(2'-methoxyphenyl)phthalimide (1): kinetic and rheometric evidence for a transition from spherical to rodlike micelles under the typical reaction conditions

Sim, Y.L. and Yusof, N.S. and Ariffin, A. and Niyaz Khan, M. (2011) Effects of nonionic micelles on the rate of alkaline hydrolysis of N-(2'-methoxyphenyl)phthalimide (1): kinetic and rheometric evidence for a transition from spherical to rodlike micelles under the typical reaction conditions. Journal of Colloid and Interface Science, 360 (1). ISSN 00219797

Full text not available from this repository. (Request a copy)
Official URL: http://www.ncbi.nlm.nih.gov/pubmed/21549387

Abstract

Pseudo-first-order rate constants (k(obs)) for alkaline hydrolysis of N-(2'-methoxyphenyl)phthalimide (1) decrease nonlinearly with increasing total concentration of nonionic surfactant C(m)E(n) (i.e. [C(m)E(n)](T) where m and n represent the respective number of methyl/methylene units in the tail and polyoxyethylene units in the headgroup of a surfactant molecule and m/n=16/20, 12/23 and 18/20) at constant 2% v/v CH(3)CN and 1.0 mM NaOH. The k(obs)vs. [C(m)E(n)](T) data follow the pseudophase micellar (PM) model at ≤ 50 mM C(16)E(20), ≤ 1.4 mM C(12)E(23) and ≤ 2.0 mM C(18)E(20) where rate of hydrolysis of 1 in micellar pseudophase could not be detected. The values of k(obs) fail to follow the PM model at > ∼50 mM C(16)E(20), > ∼1.4 mM C(12)E(23) and > ∼2.0 mM C(18)E(20) which has been attributed to a micellar structural transition from spherical to rodlike which in turn increases C(m)E(n) micellar binding constant (K(S)) of 1 with increasing values of [C(m)E(n)](T). Rheological measurements show the presence of spherical micelles at ≤ 50 mM C(16)E(20), ≤ 1.4 mM C(12)E(23) and ≤ 3.0 mM C(18)E(20). The presence of rodlike micelles is evident from rheological measurements at > ∼50 mM C(16)E(20), > ∼1.4 mM C(12)E(23) and > ∼3.0 mM C(18)E(20).

Item Type: Article
Additional Information: Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia.
Uncontrolled Keywords: Chemistry
Subjects: R Medicine
Divisions: Faculty of Science > Dept of Chemistry
Depositing User: Mr. Faizal Hamzah
Date Deposited: 04 Aug 2011 03:32
Last Modified: 11 Dec 2014 09:17
URI: http://eprints.um.edu.my/id/eprint/1931

Actions (login required)

View Item View Item