Reactions of Other Solvated Electrons

There is apparently no analog of the reaction 2eh H2 in liquid ammonia, where eam is very stable. The loss of paramagnetism in concentrated solutions has been interpreted to be either by formation of (eam)2 or by association with metal cation in neither case is the spectral shift drastic. For Na in ethylenedi-amine (EDA), Dye et al. (1972) measured the rate of 2es— (es)2 as 1.7 x 109 M s-1, which is comparable to that of the corresponding reaction in water, 6 x 109 M-1s, although the products are different. A few rate constants have been measured in cesium-EDA systems, but it is not clear whether the electron or an associated form of the electron and the cation is the reactant. 

The solvated electron is reactive in alcohols, both with solutes and solvents (Watson and Roy, 1972). With methanol, ethanol, and 1- and 2-propanols, somewhat different rates of e-solvent reactions have been measured by Freeman (1970) and by Baxendale and Wardman (1971). However, the (pseudo-first-order) rates 

Baxendale and Wardman (1973) note that the reaction of es with neutrals, such as acetone and CC14, in n-propanol is diffusion-controlled over the entire liquid phase. The values calculated from the Stokes-Einstein relation, k = 8jtRT/3jj, where 7] is the viscosity, agree well with measurement. Similarly, Fowles (1971) finds that the reaction of es with acid in alcohols is diffusion-controlled, given adequately by the Debye equation, which is not true in water. The activation energy of this reaction should be equal to that of the equivalent conductivity of es + ROH2+, which agrees well with the observation of Fowles (1971). 

Of the ethers, rate constants for es reactions are available for tetrahydrofuran (THF). Since the neutralization reaction, THF+ + es, is very fast, only fast reactions with specific rates 10u-1012 M s 1 can be studied (see Matheson, 1975, Table XXXII). Bockrath and Dorfman (1973) compared the observed rate of the reaction es + Na+ in THF, 8 x 1011 M 1s 1, with that calculated from the Debye equation, 3 x 1011 M-1s-1. Although the reaction radius is not well known, the authors note on a spectroscopic basis that Na+ and es are strongly coupled in THF Thus, the reaction of a solute with (Na+, es) in THF is much slower, sometimes by an order of magnitude, than the corresponding reaction with es only. Reaction with pyrene is an example. 

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Reaction of Other Solvated Electrons with Water... 

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