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A free review - Kinetics and mechanism of cationic micelle/flexible nanoparticle catalysis

Posted on 19. March, 2018.

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The aqueous surfactant (Surf) solution at [Surf] > cmc (critical micelle concentration) contains flexible micelles/nanoparticles. These particles form a pseudophase of different shapes and sizes where the medium polarity decreases as the distance increases from the exterior region of the interface of the Surf/H2O particle towards its furthest interior region.

Flexible nanoparticles (FNs) catalyse a variety of chemical and biochemical reactions. FN catalysis involves both positive catalysis (i.e. rate increase) and negative catalysis (i.e. rate decrease). This article describes the mechanistic details of these catalyses at the molecular level, which reveals the molecular origin of these catalyses. Effects of inert counterionic salts (MX) on the rates of bimolecular reactions (with one of the reactants as reactive counterion) in the presence of ionic FNs/micelles may result in either positive or negative catalysis. The kinetics of cationic FN Surf/MX/H2O)-catalysed bimolecular reactions (with nonionic and anionic reactants) provide kinetic parameters which can be used to determine an ion exchange constant or the ratio of the binding constants of counterions. 

Published in Progress in Reaction Kinetics and Mechanism, Volume 43, Number 1, 2018, pp. 1-20.

DOI: https://doi.org/10.3184/146867818X15066862094905

Authors: Mohammad Niyaz Khana  and Ibrahim Isah Faggea,b*
aDepartment of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
bCurrent address: Department of Chemistry, Faculty of Science, Kano University of Science and Technology, Wudil, Nigeria
*E-mail: iifagge@gmail.com

Keywords: cationic micelles, flexible nanoparticles, phenyl salicylate, N-benzylphthalimide, piperidine, hydrolysis, catalysis mechanism, ion exchange constant

Image:  A brief reaction mechanism for the alkaline hydrolysis of NBPT at 1.0 mM NaOH.