Influence of TTAB/14-S-14 Micelles on the Rate of the Condensation between Ninhydrin and Mercury-Dipeptide Complex in Absence and Presence of Salts and Organic Solvents: A Kinetic Approach
The interaction of mercury(II)–glycyl-L-alanine [Hg(II)–Gly-L-Ala]+ complex with ninhydrin has been studied kinetically both in aqueous as well as micellar media (cationic conventional/gemini surfactants) using UV-vis spectrophotometer at 70 ºC and a particular pH 5.0. The study was carried out as functions of [Hg(II)–Gly-L-Ala]+, [ninhydrin], [surfactant] [salts], and solvents (%v/v). The first-order-rate is observed concerning [Hg(II)–Gly-L-Ala]+, whereas fractional-order-rate dependence for [ninhydrin]. It has been found that 14-s-14 geminis enhance the rate of reaction more effectively than related cationic conventional surfactant tetradecyltrimethylammonium bromide (TTAB). The effect of additives such as salts (inorganic/organic) and organic solvents on the rate was also investigated. The reaction rate was explained in terms of the modified pseudo phase model (considering the association/adsorption of both the reactants on the micellar surface) and changes in micellar morphology occurring at higher [geminis]. The Eyring equation is valid for the reaction over the range of temperatures used. Various thermodynamic parameters and binding constants between reactants with the micelles have been evaluated.
Copyright (c) 2020 Adel A. M. Saeed, Taher A.A. Salem, Moh.d Akram
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.