CONTINUUM ELECTROSTATICS MODEL FOR AN S(N)2 REACTION IN SUPERCRITICALWATER

The electrostatic free energy of solvation Delta A for the S(N)2 react ion of the chloride ion with methyl chloride is calculated with a cont inuum model. The predictive capacity of the continuum electrostatic mo del is evaluated by comparing the results with simulation. This compar ison provides insight into the role of clustering (electrostriction) o f solvent about the reacting species. The results for Delta A are in r easonable agreement with simulation at high and low densities, but the model underpredicts Delta A significantly in the mid-density region. This behavior is consistent with earlier spectroscopic and simulation studies which demonstrated that clustering (electrostriction) is the m ost prevalent in the mid-density region.