The rate constant of esoiv" + S -* product (1) for inefficient reactants S is strongly dependent upon the solvation energy of electrons in the solvent. Values of ki for inefficient scavengers, such as 4-penten-2-ol, were two orders of magnitude greater in 2-methyl-2-propanol than in methanol; k1 increases in the order CH3OH < C2H5OH < 2-C3H7OH < í-C4H9OH, and the electron solvation energy changes in the opposite direction. The relative differences of for efficient scavengers are much smaller, and the above solvents fall in the reverse order; for nitrobenzene increases in the order f-C4H9OH < 2-C3H7OH < C2H5OH < CH3OH, in agreement with the relative fluidities of the solvents. Measurements in water, ethylene glycol, and 1-propanol indicate that the relative solvation of S also affects the rate. The free energies of activation AGa* of a series of scavengers in an alcohol A were compared with those in methanol, AGM*. The difference (AGM* -AGa*) reaches a limiting value [AAG*]max for inefficient scavengers. The value of [AAG*]max corresponds to the difference of free energies of activation for reaction of electron/scavenger encounter pairs in methanol and alcohol A. The values of [AAG*]max vary approximately linearly with the electron solvation energy.

. Can. J. Chem. 57,839 (1979).The rate constants kl for the reaction of solvated electrons with allyl alcohol in a number of hydroxylic solvents differ by up to two orders of magnitude and decrease in the order tertbutyl alcohol > 2-propanol > 1-propanol a ethanol > methanol a ethyleneglycol > water.In methanol and ethylene glycol the rate constants (7 x lo7 M-' s-' at 298 K) and activation energies (16 kJ/mol) are equal, in spite of a 32-fold difference in solvent viscosity (0.54 and 17.3 cP, respectively) and 3-fold difference in its activation energy (11 and 32 kJ/mol, respectively). The reaction in tert-butyl alcohol is nearly diffusion controlled and has a high activation energy that is characteristic of transport in that liquid (El = 31 kJ/mol, En = 39 kJ/mol). The activation energies in the other alcohols are all 16 kJ/mol, and it is 14 kJ/mol in water. They do not correlate with transport properties. The solvent effect is connected primarily with the entropy of activation. The rate constants correlate with the solvated electron trap depth. When the electron affinity of the scavenger is small, a favorable configuration of solvent molecules about the electronlscavenger encounter pair is required for the electron jump to take place. The behavior of the rate parameters for propargyl alcohol is similar to that for allyl alcohol, but kl, A', and El are larger for the former. The ratio k(propargyl)/k(allyl) at 298 K equals 10.5 in water and decreases through the series, reaching 1.3 in tert-butyl alcohol. Rate parameters for several other scavengers are also reported. Dans tous les autres alcools, les Cnergies d'activation sont toutes Bgales ti 16 kJ/mol; dans I'eau E, est Cgale a 14 kJ/mol. Ces valeurs ne peuvent pas Ctre reliks avec les propriCtes de transport. L'effet de solvant est principalement liC a I'entropie d'activation. I1 y a un corrtlation entre les constantes de vitesse et les profondeurs des pitges des Clectron solvatBs. Lorsque I'affinitC Clectronique pour le solutC est faible, il faut une configuration favorable des molBcules de solvant autour de la paire Clectron-solutC qui se rencontre pour que le saut Blectronique puisse s'effecteur. Le comportement des parametres de vitesse pour I'alcool propargylique est semblable a celui de I'alcool allylique; les valeurs de kl, Al et El sont toutefois plus ClevCes

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