The hydrolysis of phenyl trifluoroacetate in AOT/n-heptane RMs as a sensor of the encapsulated water structure

FERNANDO O. SILVA; RITA HOYOS DE ROSSI; N MARIANO CORREA *

RSC Advances

Royal Society of Chemistry

Lugar: Londres; Año: 2015 vol. 5 p. 34878 - 34884

2046-2069

A study was carried out on the hydrolysis of phenyl trifluoroacetate (PTFA) in AOT/n-heptane/water reversemicelles. The results obtained have been interpreted by taking into account the distribution of the PTFAusing a kinetic model based on the pseudophase concept and, it is demonstrated that the reaction takesplace in the water pool of the reverse micelles. Moreover, it is established that the water moleculesinvolved in the hydration of the interface do not react with PTFA or they do it at much slower ratecompared with the water molecules that form the pool. The value of the second order rate constant inthe water pool, kw?MI, is of the same order of magnitude as that in pure water but is greater (500 times)than those obtained in water?acetonitrile mixtures with low water content. We performed kineticsolvent isotopic effect (KSIE) and proton inventory experiments (PI) and we concluded that the water isacting as a general-base catalyst and the water sequestered in the water pool is pre-organized favoringthe activation process, in contrast to what happened in water?acetonitrile mixtures