| Abstract
| - The Diels−Alder reaction between N-ethylmaleimide and cyclopentadiene in water/AOT/isooctanemicroemulsions, where AOT denotes sodium bis(2-ethylhexyl)sulfosuccinate, was studied. The rate ofthe reaction was found to be higher than that obtained in pure isooctane, irrespective of the particularmicroemulsion composition used. The efficiency of this catalytic action ranged from a factor of 3 at lowwater contents (viz., W = [H2O]/[AOT] = 2) to 15 at W = 35. On the basis of these results, the reactiontakes place simultaneously in the continuous medium and at the microemulsion interface. The favorablearrangement of the reactants at the interface results in more than 95% of the reaction occurring in thismicroenvironment. The kinetic analysis revealed the rate constant at the microemulsion interface to changewith the water content. For small W values a bimolecular rate constant at the interface close to thatobserved in hexane was obtained. This value increases with W and for W> 20, a value close to thatobtained in ethanol was found. This can be ascribed to the absence of hydrogen bonding at themicroemulsion interface as well as the accelerating effects due to enforced hydrophobic interactions.
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