Surfactant effects upon decarboxylation of 6-nitrobenzisoxazole-3-carboxylate ion in dichloromethane. The role of head group size

Decarboxylation of 6-nitrobenzisoxazole-3-carboxylate as kinetic probe for piperazinium-based cationic micelles

“…In this pseudophase model k W and k M are first-order rate constants in the aqueous and micellar pseudophases, respectively, and K S is the association constant of substrate, S, with micellized surfactant (detergent), D n , whose concentration is the total less that of the monomer, given by the cmc. This treatment leads to the following equation, originally developed for micellar effects upon reactions of nonionic substrates, which also fits data for decarboxylation of 6-NBIC in several micellar systems [4][5][6][7][8][9][10][11][12][13][14][15]:…”

“…The sensitivity of the rate of 6-NBIC decarboxylation to medium effects makes this probe an attractive system for studying the kinetic role of interfaces and it has been extensively used to study the properties of micellar assemblies in water [6][7][8][9]11], in organic solvents [12][13][14], and recently in mixtures of water and ethanol [15]. For instance, rate effects of cationic micelles on the decarboxylation of 1 are sensitive to the nature of the counterion and the head group bulk [10].…”

“…Furthermore, the nonquaternized nitrogen may bind water molecules, and more important, may act as base. This allows the study of decarboxylation of 6-NBIC without introducing NaOH (0.01 M) or other bases as usually done in the literature [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15], allowing an investigation of possible artifacts in the kinetics due to the presence of this electrolyte at this relatively high concentration.…”

“…The reaction is catalyzed by a variety of colloidal assemblies. For example, cationic and zwitterionic micelles speed the reaction in water by incorporating 1 and providing a favorable reaction environment [4][5][6][7][8][9][10][11][12][13][14][15].…”

Chemical Characterization of Coal Tar−Water Interfacial Films

“…The only significant difference in the 1 H-NMR spectra between the coal tar film and bulk coal tar samples was observed in a region where water solvated in chlorinated solvents is typically observed (32). In general, the spectrum of a two-phase mixture of water in CDCl 3 will display a sharp resonance at 1.53 ppm for dissolved-phase water, i.e., water surrounded by adjacent CDCl 3 molecules, and a resonance at 4.8 ppm for free-phase water, i.e., water surrounded by adjacent water molecules.…”