Acceleration of chemical reaction by AOT micelles under supercritical conditions

The alkaline fading of crystal violet (CV) is accelerated by using AOT mice lles formed in supercritical ethane as a continuous phase. The rate of fadi ng can be promoted by over two orders of magnitude by controlling operating pressure and molar ratio of water to AOT(W). The structure of AOT molecule s, the type of interior water molecules, and the E-T(30) value indicative o f micropolarity of a dye-organized cybotactic region in the micelle core se em to account for the rate enhancement with an increase in the W. It is fur ther suggested that a decrease in the size of the micelle core due to signi ficant changes in the intermicellar and AOT-ethane interactions with increa sing pressure, which causes an increase in the micropolarity inside the cor e, is of importance for the promotion effect by pressure. (C) 1999 Elsevier Science Ltd. All rights reserved.