Viscosity Dependence of the Specific Rates of the Diffusion-Controlled Reactions of the Solvated Electron in Polar Solvents

In hydroxlyic solvents, the specific rates, k, of some diffusion-controlled reactions of es- with neutral molecules are proportional to ¿-n, where ¿ is the viscosity of the solvent and n is smaller than 1. This proportionality does not hold for all situations. Specifically, for alcohol-water mixtures, the relationship of k with ¿ is very complex. For some diffusion-controlled reactions of es- with neutral molecules in 1-alkanols, k is proportional to (L + X)-m, where L is the maximum linear length of the 1-alkanol molecule and X is the cavity radius of es-. Some implications of this proportionality are discussed.