Thermodynamic and Kinetic Approach of the Reactivity in Micellar Media. Reaction of 1,3,5-Trinitrobenzene upon Hydroxide Ion in Aqueous Solutions of Cationic Surfactants

Abstract

The kinetics of the reaction of OHwith 1,3,5-trinitrobenzene in the presence of dodecyl and hexadecyltrimethylammonium bromide have been studied. The micellar effects on this reaction have been modelized with the help of a new thermodynamic and kinetic analysis. This modelization has been based on a profitable approach proposed by De Donder and Defay which is well suited to the kinetics in dispersed medium. The chemical exchange rates σ V 0 and b V 0 , which are, respectively, the micellar and the bulk exchange rates, have been determined. This report also reveals that the acceleration of chemical reactions is mainly due not only to a large increase of the chemical exchange rate on the micellar aggregates but also to the high stabilization of the activated complex.

Thermodynamics and Kinetics in Micellar Media. Reaction of the Hydroxide Ion with 1,3,5-Trinitrobenzene in Aqueous Solutions of a Neutral Nonionic Surfactant. Effect of the Concentration of Background Electrolyte

“…The following relationships have been developed in our previous work. 17 We show that the molar fraction of the component i in dilute solution, in the area content, defined by and the concentration of i in the volume content b…”

“…Fundamental Aspects. We developed a thermodynamic approach in a previous paper 17 which takes into account a variable of area, σ A, in the Gibbs energy function. We have more or less associated this parameter with micellar structure, but this physical picture is not thermodynamically necessary, and we can consider that the area is a variable of dimension 2 that is indispensable in the functions of state used to describe correctly the behavior of the system.…”

“…Using the approach previously described, 17 we can analyze the way the kinetic and thermodynamic parameters of the reaction are modified by the presence of the neutral surfactant.…”

“…We used our previous approach for the interpretation of the results. 17 Some experimental values, and the main reasoning and relations, will be recalled during the discussion of the experimental values.…”

“…Pseudo-first-order conditions of the reaction were assured by using a large excess of sodium hydroxide over TNB. As for the previous study, 17 we were interested only in the formation of the monoadduct TNBOH -.…”