Kinetics and Mechanism of Counterionic Salt-Catalysed Piperidinolysis of Anionic Phenyl Salicylate in the Presence of Cationic–Nonionic Mixed Micelles

Fagge, Ibrahim I. and Ahmad, W. Hamdah W. and Md Zain, Sharifuddin and Khan, M. Niyaz (2018) Kinetics and Mechanism of Counterionic Salt-Catalysed Piperidinolysis of Anionic Phenyl Salicylate in the Presence of Cationic–Nonionic Mixed Micelles. Progress in Reaction Kinetics and Mechanism, 43 (1). pp. 41-52. ISSN 1468-6783

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Official URL: https://doi.org/10.3184/146867818X15066862094888

Abstract

The quantitative correlation of counterion-Affinity to aqueous hexadecyltrimethylammonium bromide (HDAB, cationic micelles/nanoparticles) and the counterion-induced HDAB micellar growth, in the presence of different amounts of poly(ethylene glycol hexadecyl ether) (C16E20, nonionic surfactant), was achieved by the use of a semi-empirical kinetic (SEK) method. The values of the ratio of cationic HDAB, as well as mixed HDAB-C16E20, micellar binding constants of X and Br, KX/KBr (= KX Br or RX Br ) for X = 4-ClC6H4CO2, were obtained by the SEK method. The concentration range (0.006-0.015 M) of pure HDAB was found to have no influence on the values of KX Br or RX Br These observations were also recorded upon addition of a nonionic surfactant, C16E20, in an aqueous solution of HDAB. The mean value of KX Br or RX Br obtained in the presence of pure HDAB (KX Bror RX Br = 50.3) is 2.3 times larger than that in the presence of mixed HDAB-C16E20(mKX Br or mRX Br = 21.7). From rheometric measurements of aqueous HDAClC6H4CO2-with 0.015 M HDAB, single symmetric maxima (at both 25 and 35 °C) were obtained at [4-ClC6H4CO2Na] = 0.03 M. This is evidence for the existence of wormlike micelles/nanoparticles. However, the absence of a maximum in rheometric data for aqueous HDA16E20/4-ClC6H4CO2 with 0.015 M HDAB and 0.006 M C16E20 at various [4-ClC6H4CO2Na] revealed the existence of spherical micelles.

Item Type: Article
Uncontrolled Keywords: piperidine; phenyl salicylate; micellar structural growth; semi-empirical kinetics; spherical micelles; wormlike micelles
Subjects: Q Science > Q Science (General)
Q Science > QD Chemistry
Divisions: Faculty of Science > Dept of Chemistry
Depositing User: Ms. Juhaida Abd Rahim
Date Deposited: 27 Aug 2019 03:48
Last Modified: 27 Aug 2019 03:48
URI: http://eprints.um.edu.my/id/eprint/22097

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