INFIQC   05475
INSTITUTO DE INVESTIGACIONES EN FISICO- QUIMICA DE CORDOBA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
The hydrolysis of phenyl trifluoroacetate in AOT/n-heptane RMs as a sensor of the encapsulated water structure.
Autor/es:
O FERNANDO SILVA; RITA H. DE ROSSI; N. MARIANO CORREA
Reunión:
Congreso; CLAFQO-13; 2015
Resumen:
Reversed micelles (RMs) are spatially ordered macromolecular assembly of surfactants formed in a non-polar solvent, in which the polar head groups of the surfactants point inward and the hydrocarbon chains point toward the non-polar medium.For the use of RMs as nanoreactors in aqueous phase reactions, a precise knowledge of the states of the enclosed water within the RMs is required.In this way, we performed a study on the hydrolysis of phenyl trifluoroacetate (PTFA) in AOT/n-heptane/water reverse micelle. (AOT is the sodium salt of bis(2-ethylhexyl)sulfosuccinate.) The results obtained have been interpreted by taking into account the distribution of the PTFA using a kinetic model based on the pseudo phase formalism and, we demonstrated that the reaction takes place in the water pool of reverse micelle. The values of the second order rate constants in the water pool, kw-MI, are in the order of magnitude of that in water but are greater (500 times) than those obtained in water-acetonitrile mixtures with low water content. We performed kinetic solvent isotopic effect (KSIE) concluded that the water is acting as a general-base catalyst and the water sequestered is pre-organized favoring the activation process, in contrast to what happened in water-acetonitrile mixtures.